| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * kernel/workqueue.c - generic async execution with shared worker pool |
| * |
| * Copyright (C) 2002 Ingo Molnar |
| * |
| * Derived from the taskqueue/keventd code by: |
| * David Woodhouse <dwmw2@infradead.org> |
| * Andrew Morton |
| * Kai Petzke <wpp@marie.physik.tu-berlin.de> |
| * Theodore Ts'o <tytso@mit.edu> |
| * |
| * Made to use alloc_percpu by Christoph Lameter. |
| * |
| * Copyright (C) 2010 SUSE Linux Products GmbH |
| * Copyright (C) 2010 Tejun Heo <tj@kernel.org> |
| * |
| * This is the generic async execution mechanism. Work items as are |
| * executed in process context. The worker pool is shared and |
| * automatically managed. There are two worker pools for each CPU (one for |
| * normal work items and the other for high priority ones) and some extra |
| * pools for workqueues which are not bound to any specific CPU - the |
| * number of these backing pools is dynamic. |
| * |
| * Please read Documentation/core-api/workqueue.rst for details. |
| */ |
| |
| #include <linux/export.h> |
| #include <linux/kernel.h> |
| #include <linux/sched.h> |
| #include <linux/init.h> |
| #include <linux/signal.h> |
| #include <linux/completion.h> |
| #include <linux/workqueue.h> |
| #include <linux/slab.h> |
| #include <linux/cpu.h> |
| #include <linux/notifier.h> |
| #include <linux/kthread.h> |
| #include <linux/hardirq.h> |
| #include <linux/mempolicy.h> |
| #include <linux/freezer.h> |
| #include <linux/debug_locks.h> |
| #include <linux/lockdep.h> |
| #include <linux/idr.h> |
| #include <linux/jhash.h> |
| #include <linux/hashtable.h> |
| #include <linux/rculist.h> |
| #include <linux/nodemask.h> |
| #include <linux/moduleparam.h> |
| #include <linux/uaccess.h> |
| #include <linux/sched/isolation.h> |
| #include <linux/sched/debug.h> |
| #include <linux/nmi.h> |
| #include <linux/kvm_para.h> |
| #include <linux/delay.h> |
| |
| #include "workqueue_internal.h" |
| |
| #include <trace/hooks/wqlockup.h> |
| /* events/workqueue.h uses default TRACE_INCLUDE_PATH */ |
| #undef TRACE_INCLUDE_PATH |
| |
| enum { |
| /* |
| * worker_pool flags |
| * |
| * A bound pool is either associated or disassociated with its CPU. |
| * While associated (!DISASSOCIATED), all workers are bound to the |
| * CPU and none has %WORKER_UNBOUND set and concurrency management |
| * is in effect. |
| * |
| * While DISASSOCIATED, the cpu may be offline and all workers have |
| * %WORKER_UNBOUND set and concurrency management disabled, and may |
| * be executing on any CPU. The pool behaves as an unbound one. |
| * |
| * Note that DISASSOCIATED should be flipped only while holding |
| * wq_pool_attach_mutex to avoid changing binding state while |
| * worker_attach_to_pool() is in progress. |
| */ |
| POOL_MANAGER_ACTIVE = 1 << 0, /* being managed */ |
| POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */ |
| |
| /* worker flags */ |
| WORKER_DIE = 1 << 1, /* die die die */ |
| WORKER_IDLE = 1 << 2, /* is idle */ |
| WORKER_PREP = 1 << 3, /* preparing to run works */ |
| WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ |
| WORKER_UNBOUND = 1 << 7, /* worker is unbound */ |
| WORKER_REBOUND = 1 << 8, /* worker was rebound */ |
| |
| WORKER_NOT_RUNNING = WORKER_PREP | WORKER_CPU_INTENSIVE | |
| WORKER_UNBOUND | WORKER_REBOUND, |
| |
| NR_STD_WORKER_POOLS = 2, /* # standard pools per cpu */ |
| |
| UNBOUND_POOL_HASH_ORDER = 6, /* hashed by pool->attrs */ |
| BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ |
| |
| MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ |
| IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ |
| |
| MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, |
| /* call for help after 10ms |
| (min two ticks) */ |
| MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ |
| CREATE_COOLDOWN = HZ, /* time to breath after fail */ |
| |
| /* |
| * Rescue workers are used only on emergencies and shared by |
| * all cpus. Give MIN_NICE. |
| */ |
| RESCUER_NICE_LEVEL = MIN_NICE, |
| HIGHPRI_NICE_LEVEL = MIN_NICE, |
| |
| WQ_NAME_LEN = 24, |
| }; |
| |
| /* |
| * Structure fields follow one of the following exclusion rules. |
| * |
| * I: Modifiable by initialization/destruction paths and read-only for |
| * everyone else. |
| * |
| * P: Preemption protected. Disabling preemption is enough and should |
| * only be modified and accessed from the local cpu. |
| * |
| * L: pool->lock protected. Access with pool->lock held. |
| * |
| * K: Only modified by worker while holding pool->lock. Can be safely read by |
| * self, while holding pool->lock or from IRQ context if %current is the |
| * kworker. |
| * |
| * S: Only modified by worker self. |
| * |
| * A: wq_pool_attach_mutex protected. |
| * |
| * PL: wq_pool_mutex protected. |
| * |
| * PR: wq_pool_mutex protected for writes. RCU protected for reads. |
| * |
| * PW: wq_pool_mutex and wq->mutex protected for writes. Either for reads. |
| * |
| * PWR: wq_pool_mutex and wq->mutex protected for writes. Either or |
| * RCU for reads. |
| * |
| * WQ: wq->mutex protected. |
| * |
| * WR: wq->mutex protected for writes. RCU protected for reads. |
| * |
| * MD: wq_mayday_lock protected. |
| * |
| * WD: Used internally by the watchdog. |
| */ |
| |
| /* struct worker is defined in workqueue_internal.h */ |
| |
| struct worker_pool { |
| raw_spinlock_t lock; /* the pool lock */ |
| int cpu; /* I: the associated cpu */ |
| int node; /* I: the associated node ID */ |
| int id; /* I: pool ID */ |
| unsigned int flags; /* L: flags */ |
| |
| unsigned long watchdog_ts; /* L: watchdog timestamp */ |
| bool cpu_stall; /* WD: stalled cpu bound pool */ |
| |
| /* |
| * The counter is incremented in a process context on the associated CPU |
| * w/ preemption disabled, and decremented or reset in the same context |
| * but w/ pool->lock held. The readers grab pool->lock and are |
| * guaranteed to see if the counter reached zero. |
| */ |
| int nr_running; |
| |
| struct list_head worklist; /* L: list of pending works */ |
| |
| int nr_workers; /* L: total number of workers */ |
| int nr_idle; /* L: currently idle workers */ |
| |
| struct list_head idle_list; /* L: list of idle workers */ |
| struct timer_list idle_timer; /* L: worker idle timeout */ |
| struct work_struct idle_cull_work; /* L: worker idle cleanup */ |
| |
| struct timer_list mayday_timer; /* L: SOS timer for workers */ |
| |
| /* a workers is either on busy_hash or idle_list, or the manager */ |
| DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER); |
| /* L: hash of busy workers */ |
| |
| struct worker *manager; /* L: purely informational */ |
| struct list_head workers; /* A: attached workers */ |
| struct list_head dying_workers; /* A: workers about to die */ |
| struct completion *detach_completion; /* all workers detached */ |
| |
| struct ida worker_ida; /* worker IDs for task name */ |
| |
| struct workqueue_attrs *attrs; /* I: worker attributes */ |
| struct hlist_node hash_node; /* PL: unbound_pool_hash node */ |
| int refcnt; /* PL: refcnt for unbound pools */ |
| |
| /* |
| * Destruction of pool is RCU protected to allow dereferences |
| * from get_work_pool(). |
| */ |
| struct rcu_head rcu; |
| }; |
| |
| /* |
| * Per-pool_workqueue statistics. These can be monitored using |
| * tools/workqueue/wq_monitor.py. |
| */ |
| enum pool_workqueue_stats { |
| PWQ_STAT_STARTED, /* work items started execution */ |
| PWQ_STAT_COMPLETED, /* work items completed execution */ |
| PWQ_STAT_CPU_TIME, /* total CPU time consumed */ |
| PWQ_STAT_CPU_INTENSIVE, /* wq_cpu_intensive_thresh_us violations */ |
| PWQ_STAT_CM_WAKEUP, /* concurrency-management worker wakeups */ |
| PWQ_STAT_REPATRIATED, /* unbound workers brought back into scope */ |
| PWQ_STAT_MAYDAY, /* maydays to rescuer */ |
| PWQ_STAT_RESCUED, /* linked work items executed by rescuer */ |
| |
| PWQ_NR_STATS, |
| }; |
| |
| /* |
| * The per-pool workqueue. While queued, the lower WORK_STRUCT_FLAG_BITS |
| * of work_struct->data are used for flags and the remaining high bits |
| * point to the pwq; thus, pwqs need to be aligned at two's power of the |
| * number of flag bits. |
| */ |
| struct pool_workqueue { |
| struct worker_pool *pool; /* I: the associated pool */ |
| struct workqueue_struct *wq; /* I: the owning workqueue */ |
| int work_color; /* L: current color */ |
| int flush_color; /* L: flushing color */ |
| int refcnt; /* L: reference count */ |
| int nr_in_flight[WORK_NR_COLORS]; |
| /* L: nr of in_flight works */ |
| |
| /* |
| * nr_active management and WORK_STRUCT_INACTIVE: |
| * |
| * When pwq->nr_active >= max_active, new work item is queued to |
| * pwq->inactive_works instead of pool->worklist and marked with |
| * WORK_STRUCT_INACTIVE. |
| * |
| * All work items marked with WORK_STRUCT_INACTIVE do not participate |
| * in pwq->nr_active and all work items in pwq->inactive_works are |
| * marked with WORK_STRUCT_INACTIVE. But not all WORK_STRUCT_INACTIVE |
| * work items are in pwq->inactive_works. Some of them are ready to |
| * run in pool->worklist or worker->scheduled. Those work itmes are |
| * only struct wq_barrier which is used for flush_work() and should |
| * not participate in pwq->nr_active. For non-barrier work item, it |
| * is marked with WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works. |
| */ |
| int nr_active; /* L: nr of active works */ |
| int max_active; /* L: max active works */ |
| struct list_head inactive_works; /* L: inactive works */ |
| struct list_head pwqs_node; /* WR: node on wq->pwqs */ |
| struct list_head mayday_node; /* MD: node on wq->maydays */ |
| |
| u64 stats[PWQ_NR_STATS]; |
| |
| /* |
| * Release of unbound pwq is punted to a kthread_worker. See put_pwq() |
| * and pwq_release_workfn() for details. pool_workqueue itself is also |
| * RCU protected so that the first pwq can be determined without |
| * grabbing wq->mutex. |
| */ |
| struct kthread_work release_work; |
| struct rcu_head rcu; |
| } __aligned(1 << WORK_STRUCT_FLAG_BITS); |
| |
| /* |
| * Structure used to wait for workqueue flush. |
| */ |
| struct wq_flusher { |
| struct list_head list; /* WQ: list of flushers */ |
| int flush_color; /* WQ: flush color waiting for */ |
| struct completion done; /* flush completion */ |
| }; |
| |
| struct wq_device; |
| |
| /* |
| * The externally visible workqueue. It relays the issued work items to |
| * the appropriate worker_pool through its pool_workqueues. |
| */ |
| struct workqueue_struct { |
| struct list_head pwqs; /* WR: all pwqs of this wq */ |
| struct list_head list; /* PR: list of all workqueues */ |
| |
| struct mutex mutex; /* protects this wq */ |
| int work_color; /* WQ: current work color */ |
| int flush_color; /* WQ: current flush color */ |
| atomic_t nr_pwqs_to_flush; /* flush in progress */ |
| struct wq_flusher *first_flusher; /* WQ: first flusher */ |
| struct list_head flusher_queue; /* WQ: flush waiters */ |
| struct list_head flusher_overflow; /* WQ: flush overflow list */ |
| |
| struct list_head maydays; /* MD: pwqs requesting rescue */ |
| struct worker *rescuer; /* MD: rescue worker */ |
| |
| int nr_drainers; /* WQ: drain in progress */ |
| int saved_max_active; /* WQ: saved pwq max_active */ |
| |
| struct workqueue_attrs *unbound_attrs; /* PW: only for unbound wqs */ |
| struct pool_workqueue *dfl_pwq; /* PW: only for unbound wqs */ |
| |
| #ifdef CONFIG_SYSFS |
| struct wq_device *wq_dev; /* I: for sysfs interface */ |
| #endif |
| #ifdef CONFIG_LOCKDEP |
| char *lock_name; |
| struct lock_class_key key; |
| struct lockdep_map lockdep_map; |
| #endif |
| char name[WQ_NAME_LEN]; /* I: workqueue name */ |
| |
| /* |
| * Destruction of workqueue_struct is RCU protected to allow walking |
| * the workqueues list without grabbing wq_pool_mutex. |
| * This is used to dump all workqueues from sysrq. |
| */ |
| struct rcu_head rcu; |
| |
| /* hot fields used during command issue, aligned to cacheline */ |
| unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */ |
| struct pool_workqueue __percpu __rcu **cpu_pwq; /* I: per-cpu pwqs */ |
| }; |
| |
| static struct kmem_cache *pwq_cache; |
| |
| /* |
| * Each pod type describes how CPUs should be grouped for unbound workqueues. |
| * See the comment above workqueue_attrs->affn_scope. |
| */ |
| struct wq_pod_type { |
| int nr_pods; /* number of pods */ |
| cpumask_var_t *pod_cpus; /* pod -> cpus */ |
| int *pod_node; /* pod -> node */ |
| int *cpu_pod; /* cpu -> pod */ |
| }; |
| |
| static struct wq_pod_type wq_pod_types[WQ_AFFN_NR_TYPES]; |
| static enum wq_affn_scope wq_affn_dfl = WQ_AFFN_CACHE; |
| |
| static const char *wq_affn_names[WQ_AFFN_NR_TYPES] = { |
| [WQ_AFFN_DFL] = "default", |
| [WQ_AFFN_CPU] = "cpu", |
| [WQ_AFFN_SMT] = "smt", |
| [WQ_AFFN_CACHE] = "cache", |
| [WQ_AFFN_NUMA] = "numa", |
| [WQ_AFFN_SYSTEM] = "system", |
| }; |
| |
| /* |
| * Per-cpu work items which run for longer than the following threshold are |
| * automatically considered CPU intensive and excluded from concurrency |
| * management to prevent them from noticeably delaying other per-cpu work items. |
| * ULONG_MAX indicates that the user hasn't overridden it with a boot parameter. |
| * The actual value is initialized in wq_cpu_intensive_thresh_init(). |
| */ |
| static unsigned long wq_cpu_intensive_thresh_us = ULONG_MAX; |
| module_param_named(cpu_intensive_thresh_us, wq_cpu_intensive_thresh_us, ulong, 0644); |
| |
| /* see the comment above the definition of WQ_POWER_EFFICIENT */ |
| static bool wq_power_efficient = IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DEFAULT); |
| module_param_named(power_efficient, wq_power_efficient, bool, 0444); |
| |
| static bool wq_online; /* can kworkers be created yet? */ |
| |
| /* buf for wq_update_unbound_pod_attrs(), protected by CPU hotplug exclusion */ |
| static struct workqueue_attrs *wq_update_pod_attrs_buf; |
| |
| static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */ |
| static DEFINE_MUTEX(wq_pool_attach_mutex); /* protects worker attach/detach */ |
| static DEFINE_RAW_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ |
| /* wait for manager to go away */ |
| static struct rcuwait manager_wait = __RCUWAIT_INITIALIZER(manager_wait); |
| |
| static LIST_HEAD(workqueues); /* PR: list of all workqueues */ |
| static bool workqueue_freezing; /* PL: have wqs started freezing? */ |
| |
| /* PL&A: allowable cpus for unbound wqs and work items */ |
| static cpumask_var_t wq_unbound_cpumask; |
| |
| /* for further constrain wq_unbound_cpumask by cmdline parameter*/ |
| static struct cpumask wq_cmdline_cpumask __initdata; |
| |
| /* CPU where unbound work was last round robin scheduled from this CPU */ |
| static DEFINE_PER_CPU(int, wq_rr_cpu_last); |
| |
| /* |
| * Local execution of unbound work items is no longer guaranteed. The |
| * following always forces round-robin CPU selection on unbound work items |
| * to uncover usages which depend on it. |
| */ |
| #ifdef CONFIG_DEBUG_WQ_FORCE_RR_CPU |
| static bool wq_debug_force_rr_cpu = true; |
| #else |
| static bool wq_debug_force_rr_cpu = false; |
| #endif |
| module_param_named(debug_force_rr_cpu, wq_debug_force_rr_cpu, bool, 0644); |
| |
| /* the per-cpu worker pools */ |
| static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], cpu_worker_pools); |
| |
| static DEFINE_IDR(worker_pool_idr); /* PR: idr of all pools */ |
| |
| /* PL: hash of all unbound pools keyed by pool->attrs */ |
| static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER); |
| |
| /* I: attributes used when instantiating standard unbound pools on demand */ |
| static struct workqueue_attrs *unbound_std_wq_attrs[NR_STD_WORKER_POOLS]; |
| |
| /* I: attributes used when instantiating ordered pools on demand */ |
| static struct workqueue_attrs *ordered_wq_attrs[NR_STD_WORKER_POOLS]; |
| |
| /* |
| * I: kthread_worker to release pwq's. pwq release needs to be bounced to a |
| * process context while holding a pool lock. Bounce to a dedicated kthread |
| * worker to avoid A-A deadlocks. |
| */ |
| static struct kthread_worker *pwq_release_worker; |
| |
| struct workqueue_struct *system_wq __read_mostly; |
| EXPORT_SYMBOL(system_wq); |
| struct workqueue_struct *system_highpri_wq __read_mostly; |
| EXPORT_SYMBOL_GPL(system_highpri_wq); |
| struct workqueue_struct *system_long_wq __read_mostly; |
| EXPORT_SYMBOL_GPL(system_long_wq); |
| struct workqueue_struct *system_unbound_wq __read_mostly; |
| EXPORT_SYMBOL_GPL(system_unbound_wq); |
| struct workqueue_struct *system_freezable_wq __read_mostly; |
| EXPORT_SYMBOL_GPL(system_freezable_wq); |
| struct workqueue_struct *system_power_efficient_wq __read_mostly; |
| EXPORT_SYMBOL_GPL(system_power_efficient_wq); |
| struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly; |
| EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq); |
| |
| static int worker_thread(void *__worker); |
| static void workqueue_sysfs_unregister(struct workqueue_struct *wq); |
| static void show_pwq(struct pool_workqueue *pwq); |
| static void show_one_worker_pool(struct worker_pool *pool); |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/workqueue.h> |
| |
| #define assert_rcu_or_pool_mutex() \ |
| RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \ |
| !lockdep_is_held(&wq_pool_mutex), \ |
| "RCU or wq_pool_mutex should be held") |
| |
| #define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \ |
| RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \ |
| !lockdep_is_held(&wq->mutex) && \ |
| !lockdep_is_held(&wq_pool_mutex), \ |
| "RCU, wq->mutex or wq_pool_mutex should be held") |
| |
| #define for_each_cpu_worker_pool(pool, cpu) \ |
| for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \ |
| (pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \ |
| (pool)++) |
| |
| /** |
| * for_each_pool - iterate through all worker_pools in the system |
| * @pool: iteration cursor |
| * @pi: integer used for iteration |
| * |
| * This must be called either with wq_pool_mutex held or RCU read |
| * locked. If the pool needs to be used beyond the locking in effect, the |
| * caller is responsible for guaranteeing that the pool stays online. |
| * |
| * The if/else clause exists only for the lockdep assertion and can be |
| * ignored. |
| */ |
| #define for_each_pool(pool, pi) \ |
| idr_for_each_entry(&worker_pool_idr, pool, pi) \ |
| if (({ assert_rcu_or_pool_mutex(); false; })) { } \ |
| else |
| |
| /** |
| * for_each_pool_worker - iterate through all workers of a worker_pool |
| * @worker: iteration cursor |
| * @pool: worker_pool to iterate workers of |
| * |
| * This must be called with wq_pool_attach_mutex. |
| * |
| * The if/else clause exists only for the lockdep assertion and can be |
| * ignored. |
| */ |
| #define for_each_pool_worker(worker, pool) \ |
| list_for_each_entry((worker), &(pool)->workers, node) \ |
| if (({ lockdep_assert_held(&wq_pool_attach_mutex); false; })) { } \ |
| else |
| |
| /** |
| * for_each_pwq - iterate through all pool_workqueues of the specified workqueue |
| * @pwq: iteration cursor |
| * @wq: the target workqueue |
| * |
| * This must be called either with wq->mutex held or RCU read locked. |
| * If the pwq needs to be used beyond the locking in effect, the caller is |
| * responsible for guaranteeing that the pwq stays online. |
| * |
| * The if/else clause exists only for the lockdep assertion and can be |
| * ignored. |
| */ |
| #define for_each_pwq(pwq, wq) \ |
| list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node, \ |
| lockdep_is_held(&(wq->mutex))) |
| |
| #ifdef CONFIG_DEBUG_OBJECTS_WORK |
| |
| static const struct debug_obj_descr work_debug_descr; |
| |
| static void *work_debug_hint(void *addr) |
| { |
| return ((struct work_struct *) addr)->func; |
| } |
| |
| static bool work_is_static_object(void *addr) |
| { |
| struct work_struct *work = addr; |
| |
| return test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work)); |
| } |
| |
| /* |
| * fixup_init is called when: |
| * - an active object is initialized |
| */ |
| static bool work_fixup_init(void *addr, enum debug_obj_state state) |
| { |
| struct work_struct *work = addr; |
| |
| switch (state) { |
| case ODEBUG_STATE_ACTIVE: |
| cancel_work_sync(work); |
| debug_object_init(work, &work_debug_descr); |
| return true; |
| default: |
| return false; |
| } |
| } |
| |
| /* |
| * fixup_free is called when: |
| * - an active object is freed |
| */ |
| static bool work_fixup_free(void *addr, enum debug_obj_state state) |
| { |
| struct work_struct *work = addr; |
| |
| switch (state) { |
| case ODEBUG_STATE_ACTIVE: |
| cancel_work_sync(work); |
| debug_object_free(work, &work_debug_descr); |
| return true; |
| default: |
| return false; |
| } |
| } |
| |
| static const struct debug_obj_descr work_debug_descr = { |
| .name = "work_struct", |
| .debug_hint = work_debug_hint, |
| .is_static_object = work_is_static_object, |
| .fixup_init = work_fixup_init, |
| .fixup_free = work_fixup_free, |
| }; |
| |
| static inline void debug_work_activate(struct work_struct *work) |
| { |
| debug_object_activate(work, &work_debug_descr); |
| } |
| |
| static inline void debug_work_deactivate(struct work_struct *work) |
| { |
| debug_object_deactivate(work, &work_debug_descr); |
| } |
| |
| void __init_work(struct work_struct *work, int onstack) |
| { |
| if (onstack) |
| debug_object_init_on_stack(work, &work_debug_descr); |
| else |
| debug_object_init(work, &work_debug_descr); |
| } |
| EXPORT_SYMBOL_GPL(__init_work); |
| |
| void destroy_work_on_stack(struct work_struct *work) |
| { |
| debug_object_free(work, &work_debug_descr); |
| } |
| EXPORT_SYMBOL_GPL(destroy_work_on_stack); |
| |
| void destroy_delayed_work_on_stack(struct delayed_work *work) |
| { |
| destroy_timer_on_stack(&work->timer); |
| debug_object_free(&work->work, &work_debug_descr); |
| } |
| EXPORT_SYMBOL_GPL(destroy_delayed_work_on_stack); |
| |
| #else |
| static inline void debug_work_activate(struct work_struct *work) { } |
| static inline void debug_work_deactivate(struct work_struct *work) { } |
| #endif |
| |
| /** |
| * worker_pool_assign_id - allocate ID and assign it to @pool |
| * @pool: the pool pointer of interest |
| * |
| * Returns 0 if ID in [0, WORK_OFFQ_POOL_NONE) is allocated and assigned |
| * successfully, -errno on failure. |
| */ |
| static int worker_pool_assign_id(struct worker_pool *pool) |
| { |
| int ret; |
| |
| lockdep_assert_held(&wq_pool_mutex); |
| |
| ret = idr_alloc(&worker_pool_idr, pool, 0, WORK_OFFQ_POOL_NONE, |
| GFP_KERNEL); |
| if (ret >= 0) { |
| pool->id = ret; |
| return 0; |
| } |
| return ret; |
| } |
| |
| static unsigned int work_color_to_flags(int color) |
| { |
| return color << WORK_STRUCT_COLOR_SHIFT; |
| } |
| |
| static int get_work_color(unsigned long work_data) |
| { |
| return (work_data >> WORK_STRUCT_COLOR_SHIFT) & |
| ((1 << WORK_STRUCT_COLOR_BITS) - 1); |
| } |
| |
| static int work_next_color(int color) |
| { |
| return (color + 1) % WORK_NR_COLORS; |
| } |
| |
| /* |
| * While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data |
| * contain the pointer to the queued pwq. Once execution starts, the flag |
| * is cleared and the high bits contain OFFQ flags and pool ID. |
| * |
| * set_work_pwq(), set_work_pool_and_clear_pending(), mark_work_canceling() |
| * and clear_work_data() can be used to set the pwq, pool or clear |
| * work->data. These functions should only be called while the work is |
| * owned - ie. while the PENDING bit is set. |
| * |
| * get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq |
| * corresponding to a work. Pool is available once the work has been |
| * queued anywhere after initialization until it is sync canceled. pwq is |
| * available only while the work item is queued. |
| * |
| * %WORK_OFFQ_CANCELING is used to mark a work item which is being |
| * canceled. While being canceled, a work item may have its PENDING set |
| * but stay off timer and worklist for arbitrarily long and nobody should |
| * try to steal the PENDING bit. |
| */ |
| static inline void set_work_data(struct work_struct *work, unsigned long data, |
| unsigned long flags) |
| { |
| WARN_ON_ONCE(!work_pending(work)); |
| atomic_long_set(&work->data, data | flags | work_static(work)); |
| } |
| |
| static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq, |
| unsigned long extra_flags) |
| { |
| set_work_data(work, (unsigned long)pwq, |
| WORK_STRUCT_PENDING | WORK_STRUCT_PWQ | extra_flags); |
| } |
| |
| static void set_work_pool_and_keep_pending(struct work_struct *work, |
| int pool_id) |
| { |
| set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, |
| WORK_STRUCT_PENDING); |
| } |
| |
| static void set_work_pool_and_clear_pending(struct work_struct *work, |
| int pool_id) |
| { |
| /* |
| * The following wmb is paired with the implied mb in |
| * test_and_set_bit(PENDING) and ensures all updates to @work made |
| * here are visible to and precede any updates by the next PENDING |
| * owner. |
| */ |
| smp_wmb(); |
| set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0); |
| /* |
| * The following mb guarantees that previous clear of a PENDING bit |
| * will not be reordered with any speculative LOADS or STORES from |
| * work->current_func, which is executed afterwards. This possible |
| * reordering can lead to a missed execution on attempt to queue |
| * the same @work. E.g. consider this case: |
| * |
| * CPU#0 CPU#1 |
| * ---------------------------- -------------------------------- |
| * |
| * 1 STORE event_indicated |
| * 2 queue_work_on() { |
| * 3 test_and_set_bit(PENDING) |
| * 4 } set_..._and_clear_pending() { |
| * 5 set_work_data() # clear bit |
| * 6 smp_mb() |
| * 7 work->current_func() { |
| * 8 LOAD event_indicated |
| * } |
| * |
| * Without an explicit full barrier speculative LOAD on line 8 can |
| * be executed before CPU#0 does STORE on line 1. If that happens, |
| * CPU#0 observes the PENDING bit is still set and new execution of |
| * a @work is not queued in a hope, that CPU#1 will eventually |
| * finish the queued @work. Meanwhile CPU#1 does not see |
| * event_indicated is set, because speculative LOAD was executed |
| * before actual STORE. |
| */ |
| smp_mb(); |
| } |
| |
| static void clear_work_data(struct work_struct *work) |
| { |
| smp_wmb(); /* see set_work_pool_and_clear_pending() */ |
| set_work_data(work, WORK_STRUCT_NO_POOL, 0); |
| } |
| |
| static inline struct pool_workqueue *work_struct_pwq(unsigned long data) |
| { |
| return (struct pool_workqueue *)(data & WORK_STRUCT_WQ_DATA_MASK); |
| } |
| |
| static struct pool_workqueue *get_work_pwq(struct work_struct *work) |
| { |
| unsigned long data = atomic_long_read(&work->data); |
| |
| if (data & WORK_STRUCT_PWQ) |
| return work_struct_pwq(data); |
| else |
| return NULL; |
| } |
| |
| /** |
| * get_work_pool - return the worker_pool a given work was associated with |
| * @work: the work item of interest |
| * |
| * Pools are created and destroyed under wq_pool_mutex, and allows read |
| * access under RCU read lock. As such, this function should be |
| * called under wq_pool_mutex or inside of a rcu_read_lock() region. |
| * |
| * All fields of the returned pool are accessible as long as the above |
| * mentioned locking is in effect. If the returned pool needs to be used |
| * beyond the critical section, the caller is responsible for ensuring the |
| * returned pool is and stays online. |
| * |
| * Return: The worker_pool @work was last associated with. %NULL if none. |
| */ |
| static struct worker_pool *get_work_pool(struct work_struct *work) |
| { |
| unsigned long data = atomic_long_read(&work->data); |
| int pool_id; |
| |
| assert_rcu_or_pool_mutex(); |
| |
| if (data & WORK_STRUCT_PWQ) |
| return work_struct_pwq(data)->pool; |
| |
| pool_id = data >> WORK_OFFQ_POOL_SHIFT; |
| if (pool_id == WORK_OFFQ_POOL_NONE) |
| return NULL; |
| |
| return idr_find(&worker_pool_idr, pool_id); |
| } |
| |
| /** |
| * get_work_pool_id - return the worker pool ID a given work is associated with |
| * @work: the work item of interest |
| * |
| * Return: The worker_pool ID @work was last associated with. |
| * %WORK_OFFQ_POOL_NONE if none. |
| */ |
| static int get_work_pool_id(struct work_struct *work) |
| { |
| unsigned long data = atomic_long_read(&work->data); |
| |
| if (data & WORK_STRUCT_PWQ) |
| return work_struct_pwq(data)->pool->id; |
| |
| return data >> WORK_OFFQ_POOL_SHIFT; |
| } |
| |
| static void mark_work_canceling(struct work_struct *work) |
| { |
| unsigned long pool_id = get_work_pool_id(work); |
| |
| pool_id <<= WORK_OFFQ_POOL_SHIFT; |
| set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING); |
| } |
| |
| static bool work_is_canceling(struct work_struct *work) |
| { |
| unsigned long data = atomic_long_read(&work->data); |
| |
| return !(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_CANCELING); |
| } |
| |
| /* |
| * Policy functions. These define the policies on how the global worker |
| * pools are managed. Unless noted otherwise, these functions assume that |
| * they're being called with pool->lock held. |
| */ |
| |
| /* |
| * Need to wake up a worker? Called from anything but currently |
| * running workers. |
| * |
| * Note that, because unbound workers never contribute to nr_running, this |
| * function will always return %true for unbound pools as long as the |
| * worklist isn't empty. |
| */ |
| static bool need_more_worker(struct worker_pool *pool) |
| { |
| return !list_empty(&pool->worklist) && !pool->nr_running; |
| } |
| |
| /* Can I start working? Called from busy but !running workers. */ |
| static bool may_start_working(struct worker_pool *pool) |
| { |
| return pool->nr_idle; |
| } |
| |
| /* Do I need to keep working? Called from currently running workers. */ |
| static bool keep_working(struct worker_pool *pool) |
| { |
| return !list_empty(&pool->worklist) && (pool->nr_running <= 1); |
| } |
| |
| /* Do we need a new worker? Called from manager. */ |
| static bool need_to_create_worker(struct worker_pool *pool) |
| { |
| return need_more_worker(pool) && !may_start_working(pool); |
| } |
| |
| /* Do we have too many workers and should some go away? */ |
| static bool too_many_workers(struct worker_pool *pool) |
| { |
| bool managing = pool->flags & POOL_MANAGER_ACTIVE; |
| int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ |
| int nr_busy = pool->nr_workers - nr_idle; |
| |
| return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; |
| } |
| |
| /** |
| * worker_set_flags - set worker flags and adjust nr_running accordingly |
| * @worker: self |
| * @flags: flags to set |
| * |
| * Set @flags in @worker->flags and adjust nr_running accordingly. |
| */ |
| static inline void worker_set_flags(struct worker *worker, unsigned int flags) |
| { |
| struct worker_pool *pool = worker->pool; |
| |
| lockdep_assert_held(&pool->lock); |
| |
| /* If transitioning into NOT_RUNNING, adjust nr_running. */ |
| if ((flags & WORKER_NOT_RUNNING) && |
| !(worker->flags & WORKER_NOT_RUNNING)) { |
| pool->nr_running--; |
| } |
| |
| worker->flags |= flags; |
| } |
| |
| /** |
| * worker_clr_flags - clear worker flags and adjust nr_running accordingly |
| * @worker: self |
| * @flags: flags to clear |
| * |
| * Clear @flags in @worker->flags and adjust nr_running accordingly. |
| */ |
| static inline void worker_clr_flags(struct worker *worker, unsigned int flags) |
| { |
| struct worker_pool *pool = worker->pool; |
| unsigned int oflags = worker->flags; |
| |
| lockdep_assert_held(&pool->lock); |
| |
| worker->flags &= ~flags; |
| |
| /* |
| * If transitioning out of NOT_RUNNING, increment nr_running. Note |
| * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask |
| * of multiple flags, not a single flag. |
| */ |
| if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) |
| if (!(worker->flags & WORKER_NOT_RUNNING)) |
| pool->nr_running++; |
| } |
| |
| /* Return the first idle worker. Called with pool->lock held. */ |
| static struct worker *first_idle_worker(struct worker_pool *pool) |
| { |
| if (unlikely(list_empty(&pool->idle_list))) |
| return NULL; |
| |
| return list_first_entry(&pool->idle_list, struct worker, entry); |
| } |
| |
| /** |
| * worker_enter_idle - enter idle state |
| * @worker: worker which is entering idle state |
| * |
| * @worker is entering idle state. Update stats and idle timer if |
| * necessary. |
| * |
| * LOCKING: |
| * raw_spin_lock_irq(pool->lock). |
| */ |
| static void worker_enter_idle(struct worker *worker) |
| { |
| struct worker_pool *pool = worker->pool; |
| |
| if (WARN_ON_ONCE(worker->flags & WORKER_IDLE) || |
| WARN_ON_ONCE(!list_empty(&worker->entry) && |
| (worker->hentry.next || worker->hentry.pprev))) |
| return; |
| |
| /* can't use worker_set_flags(), also called from create_worker() */ |
| worker->flags |= WORKER_IDLE; |
| pool->nr_idle++; |
| worker->last_active = jiffies; |
| |
| /* idle_list is LIFO */ |
| list_add(&worker->entry, &pool->idle_list); |
| |
| if (too_many_workers(pool) && !timer_pending(&pool->idle_timer)) |
| mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT); |
| |
| /* Sanity check nr_running. */ |
| WARN_ON_ONCE(pool->nr_workers == pool->nr_idle && pool->nr_running); |
| } |
| |
| /** |
| * worker_leave_idle - leave idle state |
| * @worker: worker which is leaving idle state |
| * |
| * @worker is leaving idle state. Update stats. |
| * |
| * LOCKING: |
| * raw_spin_lock_irq(pool->lock). |
| */ |
| static void worker_leave_idle(struct worker *worker) |
| { |
| struct worker_pool *pool = worker->pool; |
| |
| if (WARN_ON_ONCE(!(worker->flags & WORKER_IDLE))) |
| return; |
| worker_clr_flags(worker, WORKER_IDLE); |
| pool->nr_idle--; |
| list_del_init(&worker->entry); |
| } |
| |
| /** |
| * find_worker_executing_work - find worker which is executing a work |
| * @pool: pool of interest |
| * @work: work to find worker for |
| * |
| * Find a worker which is executing @work on @pool by searching |
| * @pool->busy_hash which is keyed by the address of @work. For a worker |
| * to match, its current execution should match the address of @work and |
| * its work function. This is to avoid unwanted dependency between |
| * unrelated work executions through a work item being recycled while still |
| * being executed. |
| * |
| * This is a bit tricky. A work item may be freed once its execution |
| * starts and nothing prevents the freed area from being recycled for |
| * another work item. If the same work item address ends up being reused |
| * before the original execution finishes, workqueue will identify the |
| * recycled work item as currently executing and make it wait until the |
| * current execution finishes, introducing an unwanted dependency. |
| * |
| * This function checks the work item address and work function to avoid |
| * false positives. Note that this isn't complete as one may construct a |
| * work function which can introduce dependency onto itself through a |
| * recycled work item. Well, if somebody wants to shoot oneself in the |
| * foot that badly, there's only so much we can do, and if such deadlock |
| * actually occurs, it should be easy to locate the culprit work function. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(pool->lock). |
| * |
| * Return: |
| * Pointer to worker which is executing @work if found, %NULL |
| * otherwise. |
| */ |
| static struct worker *find_worker_executing_work(struct worker_pool *pool, |
| struct work_struct *work) |
| { |
| struct worker *worker; |
| |
| hash_for_each_possible(pool->busy_hash, worker, hentry, |
| (unsigned long)work) |
| if (worker->current_work == work && |
| worker->current_func == work->func) |
| return worker; |
| |
| return NULL; |
| } |
| |
| /** |
| * move_linked_works - move linked works to a list |
| * @work: start of series of works to be scheduled |
| * @head: target list to append @work to |
| * @nextp: out parameter for nested worklist walking |
| * |
| * Schedule linked works starting from @work to @head. Work series to be |
| * scheduled starts at @work and includes any consecutive work with |
| * WORK_STRUCT_LINKED set in its predecessor. See assign_work() for details on |
| * @nextp. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(pool->lock). |
| */ |
| static void move_linked_works(struct work_struct *work, struct list_head *head, |
| struct work_struct **nextp) |
| { |
| struct work_struct *n; |
| |
| /* |
| * Linked worklist will always end before the end of the list, |
| * use NULL for list head. |
| */ |
| list_for_each_entry_safe_from(work, n, NULL, entry) { |
| list_move_tail(&work->entry, head); |
| if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) |
| break; |
| } |
| |
| /* |
| * If we're already inside safe list traversal and have moved |
| * multiple works to the scheduled queue, the next position |
| * needs to be updated. |
| */ |
| if (nextp) |
| *nextp = n; |
| } |
| |
| /** |
| * assign_work - assign a work item and its linked work items to a worker |
| * @work: work to assign |
| * @worker: worker to assign to |
| * @nextp: out parameter for nested worklist walking |
| * |
| * Assign @work and its linked work items to @worker. If @work is already being |
| * executed by another worker in the same pool, it'll be punted there. |
| * |
| * If @nextp is not NULL, it's updated to point to the next work of the last |
| * scheduled work. This allows assign_work() to be nested inside |
| * list_for_each_entry_safe(). |
| * |
| * Returns %true if @work was successfully assigned to @worker. %false if @work |
| * was punted to another worker already executing it. |
| */ |
| static bool assign_work(struct work_struct *work, struct worker *worker, |
| struct work_struct **nextp) |
| { |
| struct worker_pool *pool = worker->pool; |
| struct worker *collision; |
| |
| lockdep_assert_held(&pool->lock); |
| |
| /* |
| * A single work shouldn't be executed concurrently by multiple workers. |
| * __queue_work() ensures that @work doesn't jump to a different pool |
| * while still running in the previous pool. Here, we should ensure that |
| * @work is not executed concurrently by multiple workers from the same |
| * pool. Check whether anyone is already processing the work. If so, |
| * defer the work to the currently executing one. |
| */ |
| collision = find_worker_executing_work(pool, work); |
| if (unlikely(collision)) { |
| move_linked_works(work, &collision->scheduled, nextp); |
| return false; |
| } |
| |
| move_linked_works(work, &worker->scheduled, nextp); |
| return true; |
| } |
| |
| /** |
| * kick_pool - wake up an idle worker if necessary |
| * @pool: pool to kick |
| * |
| * @pool may have pending work items. Wake up worker if necessary. Returns |
| * whether a worker was woken up. |
| */ |
| static bool kick_pool(struct worker_pool *pool) |
| { |
| struct worker *worker = first_idle_worker(pool); |
| struct task_struct *p; |
| |
| lockdep_assert_held(&pool->lock); |
| |
| if (!need_more_worker(pool) || !worker) |
| return false; |
| |
| p = worker->task; |
| |
| #ifdef CONFIG_SMP |
| /* |
| * Idle @worker is about to execute @work and waking up provides an |
| * opportunity to migrate @worker at a lower cost by setting the task's |
| * wake_cpu field. Let's see if we want to move @worker to improve |
| * execution locality. |
| * |
| * We're waking the worker that went idle the latest and there's some |
| * chance that @worker is marked idle but hasn't gone off CPU yet. If |
| * so, setting the wake_cpu won't do anything. As this is a best-effort |
| * optimization and the race window is narrow, let's leave as-is for |
| * now. If this becomes pronounced, we can skip over workers which are |
| * still on cpu when picking an idle worker. |
| * |
| * If @pool has non-strict affinity, @worker might have ended up outside |
| * its affinity scope. Repatriate. |
| */ |
| if (!pool->attrs->affn_strict && |
| !cpumask_test_cpu(p->wake_cpu, pool->attrs->__pod_cpumask)) { |
| struct work_struct *work = list_first_entry(&pool->worklist, |
| struct work_struct, entry); |
| p->wake_cpu = cpumask_any_distribute(pool->attrs->__pod_cpumask); |
| get_work_pwq(work)->stats[PWQ_STAT_REPATRIATED]++; |
| } |
| #endif |
| wake_up_process(p); |
| return true; |
| } |
| |
| #ifdef CONFIG_WQ_CPU_INTENSIVE_REPORT |
| |
| /* |
| * Concurrency-managed per-cpu work items that hog CPU for longer than |
| * wq_cpu_intensive_thresh_us trigger the automatic CPU_INTENSIVE mechanism, |
| * which prevents them from stalling other concurrency-managed work items. If a |
| * work function keeps triggering this mechanism, it's likely that the work item |
| * should be using an unbound workqueue instead. |
| * |
| * wq_cpu_intensive_report() tracks work functions which trigger such conditions |
| * and report them so that they can be examined and converted to use unbound |
| * workqueues as appropriate. To avoid flooding the console, each violating work |
| * function is tracked and reported with exponential backoff. |
| */ |
| #define WCI_MAX_ENTS 128 |
| |
| struct wci_ent { |
| work_func_t func; |
| atomic64_t cnt; |
| struct hlist_node hash_node; |
| }; |
| |
| static struct wci_ent wci_ents[WCI_MAX_ENTS]; |
| static int wci_nr_ents; |
| static DEFINE_RAW_SPINLOCK(wci_lock); |
| static DEFINE_HASHTABLE(wci_hash, ilog2(WCI_MAX_ENTS)); |
| |
| static struct wci_ent *wci_find_ent(work_func_t func) |
| { |
| struct wci_ent *ent; |
| |
| hash_for_each_possible_rcu(wci_hash, ent, hash_node, |
| (unsigned long)func) { |
| if (ent->func == func) |
| return ent; |
| } |
| return NULL; |
| } |
| |
| static void wq_cpu_intensive_report(work_func_t func) |
| { |
| struct wci_ent *ent; |
| |
| restart: |
| ent = wci_find_ent(func); |
| if (ent) { |
| u64 cnt; |
| |
| /* |
| * Start reporting from the fourth time and back off |
| * exponentially. |
| */ |
| cnt = atomic64_inc_return_relaxed(&ent->cnt); |
| if (cnt >= 4 && is_power_of_2(cnt)) |
| printk_deferred(KERN_WARNING "workqueue: %ps hogged CPU for >%luus %llu times, consider switching to WQ_UNBOUND\n", |
| ent->func, wq_cpu_intensive_thresh_us, |
| atomic64_read(&ent->cnt)); |
| return; |
| } |
| |
| /* |
| * @func is a new violation. Allocate a new entry for it. If wcn_ents[] |
| * is exhausted, something went really wrong and we probably made enough |
| * noise already. |
| */ |
| if (wci_nr_ents >= WCI_MAX_ENTS) |
| return; |
| |
| raw_spin_lock(&wci_lock); |
| |
| if (wci_nr_ents >= WCI_MAX_ENTS) { |
| raw_spin_unlock(&wci_lock); |
| return; |
| } |
| |
| if (wci_find_ent(func)) { |
| raw_spin_unlock(&wci_lock); |
| goto restart; |
| } |
| |
| ent = &wci_ents[wci_nr_ents++]; |
| ent->func = func; |
| atomic64_set(&ent->cnt, 1); |
| hash_add_rcu(wci_hash, &ent->hash_node, (unsigned long)func); |
| |
| raw_spin_unlock(&wci_lock); |
| } |
| |
| #else /* CONFIG_WQ_CPU_INTENSIVE_REPORT */ |
| static void wq_cpu_intensive_report(work_func_t func) {} |
| #endif /* CONFIG_WQ_CPU_INTENSIVE_REPORT */ |
| |
| /** |
| * wq_worker_running - a worker is running again |
| * @task: task waking up |
| * |
| * This function is called when a worker returns from schedule() |
| */ |
| void wq_worker_running(struct task_struct *task) |
| { |
| struct worker *worker = kthread_data(task); |
| |
| if (!READ_ONCE(worker->sleeping)) |
| return; |
| |
| /* |
| * If preempted by unbind_workers() between the WORKER_NOT_RUNNING check |
| * and the nr_running increment below, we may ruin the nr_running reset |
| * and leave with an unexpected pool->nr_running == 1 on the newly unbound |
| * pool. Protect against such race. |
| */ |
| preempt_disable(); |
| if (!(worker->flags & WORKER_NOT_RUNNING)) |
| worker->pool->nr_running++; |
| preempt_enable(); |
| |
| /* |
| * CPU intensive auto-detection cares about how long a work item hogged |
| * CPU without sleeping. Reset the starting timestamp on wakeup. |
| */ |
| worker->current_at = worker->task->se.sum_exec_runtime; |
| |
| WRITE_ONCE(worker->sleeping, 0); |
| } |
| |
| /** |
| * wq_worker_sleeping - a worker is going to sleep |
| * @task: task going to sleep |
| * |
| * This function is called from schedule() when a busy worker is |
| * going to sleep. |
| */ |
| void wq_worker_sleeping(struct task_struct *task) |
| { |
| struct worker *worker = kthread_data(task); |
| struct worker_pool *pool; |
| |
| /* |
| * Rescuers, which may not have all the fields set up like normal |
| * workers, also reach here, let's not access anything before |
| * checking NOT_RUNNING. |
| */ |
| if (worker->flags & WORKER_NOT_RUNNING) |
| return; |
| |
| pool = worker->pool; |
| |
| /* Return if preempted before wq_worker_running() was reached */ |
| if (READ_ONCE(worker->sleeping)) |
| return; |
| |
| WRITE_ONCE(worker->sleeping, 1); |
| raw_spin_lock_irq(&pool->lock); |
| |
| /* |
| * Recheck in case unbind_workers() preempted us. We don't |
| * want to decrement nr_running after the worker is unbound |
| * and nr_running has been reset. |
| */ |
| if (worker->flags & WORKER_NOT_RUNNING) { |
| raw_spin_unlock_irq(&pool->lock); |
| return; |
| } |
| |
| pool->nr_running--; |
| if (kick_pool(pool)) |
| worker->current_pwq->stats[PWQ_STAT_CM_WAKEUP]++; |
| |
| raw_spin_unlock_irq(&pool->lock); |
| } |
| |
| /** |
| * wq_worker_tick - a scheduler tick occurred while a kworker is running |
| * @task: task currently running |
| * |
| * Called from scheduler_tick(). We're in the IRQ context and the current |
| * worker's fields which follow the 'K' locking rule can be accessed safely. |
| */ |
| void wq_worker_tick(struct task_struct *task) |
| { |
| struct worker *worker = kthread_data(task); |
| struct pool_workqueue *pwq = worker->current_pwq; |
| struct worker_pool *pool = worker->pool; |
| |
| if (!pwq) |
| return; |
| |
| pwq->stats[PWQ_STAT_CPU_TIME] += TICK_USEC; |
| |
| if (!wq_cpu_intensive_thresh_us) |
| return; |
| |
| /* |
| * If the current worker is concurrency managed and hogged the CPU for |
| * longer than wq_cpu_intensive_thresh_us, it's automatically marked |
| * CPU_INTENSIVE to avoid stalling other concurrency-managed work items. |
| * |
| * Set @worker->sleeping means that @worker is in the process of |
| * switching out voluntarily and won't be contributing to |
| * @pool->nr_running until it wakes up. As wq_worker_sleeping() also |
| * decrements ->nr_running, setting CPU_INTENSIVE here can lead to |
| * double decrements. The task is releasing the CPU anyway. Let's skip. |
| * We probably want to make this prettier in the future. |
| */ |
| if ((worker->flags & WORKER_NOT_RUNNING) || READ_ONCE(worker->sleeping) || |
| worker->task->se.sum_exec_runtime - worker->current_at < |
| wq_cpu_intensive_thresh_us * NSEC_PER_USEC) |
| return; |
| |
| raw_spin_lock(&pool->lock); |
| |
| worker_set_flags(worker, WORKER_CPU_INTENSIVE); |
| wq_cpu_intensive_report(worker->current_func); |
| pwq->stats[PWQ_STAT_CPU_INTENSIVE]++; |
| |
| if (kick_pool(pool)) |
| pwq->stats[PWQ_STAT_CM_WAKEUP]++; |
| |
| raw_spin_unlock(&pool->lock); |
| } |
| |
| /** |
| * wq_worker_last_func - retrieve worker's last work function |
| * @task: Task to retrieve last work function of. |
| * |
| * Determine the last function a worker executed. This is called from |
| * the scheduler to get a worker's last known identity. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(rq->lock) |
| * |
| * This function is called during schedule() when a kworker is going |
| * to sleep. It's used by psi to identify aggregation workers during |
| * dequeuing, to allow periodic aggregation to shut-off when that |
| * worker is the last task in the system or cgroup to go to sleep. |
| * |
| * As this function doesn't involve any workqueue-related locking, it |
| * only returns stable values when called from inside the scheduler's |
| * queuing and dequeuing paths, when @task, which must be a kworker, |
| * is guaranteed to not be processing any works. |
| * |
| * Return: |
| * The last work function %current executed as a worker, NULL if it |
| * hasn't executed any work yet. |
| */ |
| work_func_t wq_worker_last_func(struct task_struct *task) |
| { |
| struct worker *worker = kthread_data(task); |
| |
| return worker->last_func; |
| } |
| |
| /** |
| * get_pwq - get an extra reference on the specified pool_workqueue |
| * @pwq: pool_workqueue to get |
| * |
| * Obtain an extra reference on @pwq. The caller should guarantee that |
| * @pwq has positive refcnt and be holding the matching pool->lock. |
| */ |
| static void get_pwq(struct pool_workqueue *pwq) |
| { |
| lockdep_assert_held(&pwq->pool->lock); |
| WARN_ON_ONCE(pwq->refcnt <= 0); |
| pwq->refcnt++; |
| } |
| |
| /** |
| * put_pwq - put a pool_workqueue reference |
| * @pwq: pool_workqueue to put |
| * |
| * Drop a reference of @pwq. If its refcnt reaches zero, schedule its |
| * destruction. The caller should be holding the matching pool->lock. |
| */ |
| static void put_pwq(struct pool_workqueue *pwq) |
| { |
| lockdep_assert_held(&pwq->pool->lock); |
| if (likely(--pwq->refcnt)) |
| return; |
| /* |
| * @pwq can't be released under pool->lock, bounce to a dedicated |
| * kthread_worker to avoid A-A deadlocks. |
| */ |
| kthread_queue_work(pwq_release_worker, &pwq->release_work); |
| } |
| |
| /** |
| * put_pwq_unlocked - put_pwq() with surrounding pool lock/unlock |
| * @pwq: pool_workqueue to put (can be %NULL) |
| * |
| * put_pwq() with locking. This function also allows %NULL @pwq. |
| */ |
| static void put_pwq_unlocked(struct pool_workqueue *pwq) |
| { |
| if (pwq) { |
| /* |
| * As both pwqs and pools are RCU protected, the |
| * following lock operations are safe. |
| */ |
| raw_spin_lock_irq(&pwq->pool->lock); |
| put_pwq(pwq); |
| raw_spin_unlock_irq(&pwq->pool->lock); |
| } |
| } |
| |
| static void pwq_activate_inactive_work(struct work_struct *work) |
| { |
| struct pool_workqueue *pwq = get_work_pwq(work); |
| |
| trace_workqueue_activate_work(work); |
| if (list_empty(&pwq->pool->worklist)) |
| pwq->pool->watchdog_ts = jiffies; |
| move_linked_works(work, &pwq->pool->worklist, NULL); |
| __clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work)); |
| pwq->nr_active++; |
| } |
| |
| static void pwq_activate_first_inactive(struct pool_workqueue *pwq) |
| { |
| struct work_struct *work = list_first_entry(&pwq->inactive_works, |
| struct work_struct, entry); |
| |
| pwq_activate_inactive_work(work); |
| } |
| |
| /** |
| * pwq_dec_nr_in_flight - decrement pwq's nr_in_flight |
| * @pwq: pwq of interest |
| * @work_data: work_data of work which left the queue |
| * |
| * A work either has completed or is removed from pending queue, |
| * decrement nr_in_flight of its pwq and handle workqueue flushing. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(pool->lock). |
| */ |
| static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, unsigned long work_data) |
| { |
| int color = get_work_color(work_data); |
| |
| if (!(work_data & WORK_STRUCT_INACTIVE)) { |
| pwq->nr_active--; |
| if (!list_empty(&pwq->inactive_works)) { |
| /* one down, submit an inactive one */ |
| if (pwq->nr_active < pwq->max_active) |
| pwq_activate_first_inactive(pwq); |
| } |
| } |
| |
| pwq->nr_in_flight[color]--; |
| |
| /* is flush in progress and are we at the flushing tip? */ |
| if (likely(pwq->flush_color != color)) |
| goto out_put; |
| |
| /* are there still in-flight works? */ |
| if (pwq->nr_in_flight[color]) |
| goto out_put; |
| |
| /* this pwq is done, clear flush_color */ |
| pwq->flush_color = -1; |
| |
| /* |
| * If this was the last pwq, wake up the first flusher. It |
| * will handle the rest. |
| */ |
| if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush)) |
| complete(&pwq->wq->first_flusher->done); |
| out_put: |
| put_pwq(pwq); |
| } |
| |
| /** |
| * try_to_grab_pending - steal work item from worklist and disable irq |
| * @work: work item to steal |
| * @is_dwork: @work is a delayed_work |
| * @flags: place to store irq state |
| * |
| * Try to grab PENDING bit of @work. This function can handle @work in any |
| * stable state - idle, on timer or on worklist. |
| * |
| * Return: |
| * |
| * ======== ================================================================ |
| * 1 if @work was pending and we successfully stole PENDING |
| * 0 if @work was idle and we claimed PENDING |
| * -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry |
| * -ENOENT if someone else is canceling @work, this state may persist |
| * for arbitrarily long |
| * ======== ================================================================ |
| * |
| * Note: |
| * On >= 0 return, the caller owns @work's PENDING bit. To avoid getting |
| * interrupted while holding PENDING and @work off queue, irq must be |
| * disabled on entry. This, combined with delayed_work->timer being |
| * irqsafe, ensures that we return -EAGAIN for finite short period of time. |
| * |
| * On successful return, >= 0, irq is disabled and the caller is |
| * responsible for releasing it using local_irq_restore(*@flags). |
| * |
| * This function is safe to call from any context including IRQ handler. |
| */ |
| static int try_to_grab_pending(struct work_struct *work, bool is_dwork, |
| unsigned long *flags) |
| { |
| struct worker_pool *pool; |
| struct pool_workqueue *pwq; |
| |
| local_irq_save(*flags); |
| |
| /* try to steal the timer if it exists */ |
| if (is_dwork) { |
| struct delayed_work *dwork = to_delayed_work(work); |
| |
| /* |
| * dwork->timer is irqsafe. If del_timer() fails, it's |
| * guaranteed that the timer is not queued anywhere and not |
| * running on the local CPU. |
| */ |
| if (likely(del_timer(&dwork->timer))) |
| return 1; |
| } |
| |
| /* try to claim PENDING the normal way */ |
| if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) |
| return 0; |
| |
| rcu_read_lock(); |
| /* |
| * The queueing is in progress, or it is already queued. Try to |
| * steal it from ->worklist without clearing WORK_STRUCT_PENDING. |
| */ |
| pool = get_work_pool(work); |
| if (!pool) |
| goto fail; |
| |
| raw_spin_lock(&pool->lock); |
| /* |
| * work->data is guaranteed to point to pwq only while the work |
| * item is queued on pwq->wq, and both updating work->data to point |
| * to pwq on queueing and to pool on dequeueing are done under |
| * pwq->pool->lock. This in turn guarantees that, if work->data |
| * points to pwq which is associated with a locked pool, the work |
| * item is currently queued on that pool. |
| */ |
| pwq = get_work_pwq(work); |
| if (pwq && pwq->pool == pool) { |
| debug_work_deactivate(work); |
| |
| /* |
| * A cancelable inactive work item must be in the |
| * pwq->inactive_works since a queued barrier can't be |
| * canceled (see the comments in insert_wq_barrier()). |
| * |
| * An inactive work item cannot be grabbed directly because |
| * it might have linked barrier work items which, if left |
| * on the inactive_works list, will confuse pwq->nr_active |
| * management later on and cause stall. Make sure the work |
| * item is activated before grabbing. |
| */ |
| if (*work_data_bits(work) & WORK_STRUCT_INACTIVE) |
| pwq_activate_inactive_work(work); |
| |
| list_del_init(&work->entry); |
| pwq_dec_nr_in_flight(pwq, *work_data_bits(work)); |
| |
| /* work->data points to pwq iff queued, point to pool */ |
| set_work_pool_and_keep_pending(work, pool->id); |
| |
| raw_spin_unlock(&pool->lock); |
| rcu_read_unlock(); |
| return 1; |
| } |
| raw_spin_unlock(&pool->lock); |
| fail: |
| rcu_read_unlock(); |
| local_irq_restore(*flags); |
| if (work_is_canceling(work)) |
| return -ENOENT; |
| cpu_relax(); |
| return -EAGAIN; |
| } |
| |
| /** |
| * insert_work - insert a work into a pool |
| * @pwq: pwq @work belongs to |
| * @work: work to insert |
| * @head: insertion point |
| * @extra_flags: extra WORK_STRUCT_* flags to set |
| * |
| * Insert @work which belongs to @pwq after @head. @extra_flags is or'd to |
| * work_struct flags. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(pool->lock). |
| */ |
| static void insert_work(struct pool_workqueue *pwq, struct work_struct *work, |
| struct list_head *head, unsigned int extra_flags) |
| { |
| debug_work_activate(work); |
| |
| /* record the work call stack in order to print it in KASAN reports */ |
| kasan_record_aux_stack_noalloc(work); |
| |
| /* we own @work, set data and link */ |
| set_work_pwq(work, pwq, extra_flags); |
| list_add_tail(&work->entry, head); |
| get_pwq(pwq); |
| } |
| |
| /* |
| * Test whether @work is being queued from another work executing on the |
| * same workqueue. |
| */ |
| static bool is_chained_work(struct workqueue_struct *wq) |
| { |
| struct worker *worker; |
| |
| worker = current_wq_worker(); |
| /* |
| * Return %true iff I'm a worker executing a work item on @wq. If |
| * I'm @worker, it's safe to dereference it without locking. |
| */ |
| return worker && worker->current_pwq->wq == wq; |
| } |
| |
| /* |
| * When queueing an unbound work item to a wq, prefer local CPU if allowed |
| * by wq_unbound_cpumask. Otherwise, round robin among the allowed ones to |
| * avoid perturbing sensitive tasks. |
| */ |
| static int wq_select_unbound_cpu(int cpu) |
| { |
| int new_cpu; |
| |
| if (likely(!wq_debug_force_rr_cpu)) { |
| if (cpumask_test_cpu(cpu, wq_unbound_cpumask)) |
| return cpu; |
| } else { |
| pr_warn_once("workqueue: round-robin CPU selection forced, expect performance impact\n"); |
| } |
| |
| if (cpumask_empty(wq_unbound_cpumask)) |
| return cpu; |
| |
| new_cpu = __this_cpu_read(wq_rr_cpu_last); |
| new_cpu = cpumask_next_and(new_cpu, wq_unbound_cpumask, cpu_online_mask); |
| if (unlikely(new_cpu >= nr_cpu_ids)) { |
| new_cpu = cpumask_first_and(wq_unbound_cpumask, cpu_online_mask); |
| if (unlikely(new_cpu >= nr_cpu_ids)) |
| return cpu; |
| } |
| __this_cpu_write(wq_rr_cpu_last, new_cpu); |
| |
| return new_cpu; |
| } |
| |
| static void __queue_work(int cpu, struct workqueue_struct *wq, |
| struct work_struct *work) |
| { |
| struct pool_workqueue *pwq; |
| struct worker_pool *last_pool, *pool; |
| unsigned int work_flags; |
| unsigned int req_cpu = cpu; |
| |
| /* |
| * While a work item is PENDING && off queue, a task trying to |
| * steal the PENDING will busy-loop waiting for it to either get |
| * queued or lose PENDING. Grabbing PENDING and queueing should |
| * happen with IRQ disabled. |
| */ |
| lockdep_assert_irqs_disabled(); |
| |
| |
| /* |
| * For a draining wq, only works from the same workqueue are |
| * allowed. The __WQ_DESTROYING helps to spot the issue that |
| * queues a new work item to a wq after destroy_workqueue(wq). |
| */ |
| if (unlikely(wq->flags & (__WQ_DESTROYING | __WQ_DRAINING) && |
| WARN_ON_ONCE(!is_chained_work(wq)))) |
| return; |
| rcu_read_lock(); |
| retry: |
| /* pwq which will be used unless @work is executing elsewhere */ |
| if (req_cpu == WORK_CPU_UNBOUND) { |
| if (wq->flags & WQ_UNBOUND) |
| cpu = wq_select_unbound_cpu(raw_smp_processor_id()); |
| else |
| cpu = raw_smp_processor_id(); |
| } |
| |
| pwq = rcu_dereference(*per_cpu_ptr(wq->cpu_pwq, cpu)); |
| pool = pwq->pool; |
| |
| /* |
| * If @work was previously on a different pool, it might still be |
| * running there, in which case the work needs to be queued on that |
| * pool to guarantee non-reentrancy. |
| */ |
| last_pool = get_work_pool(work); |
| if (last_pool && last_pool != pool) { |
| struct worker *worker; |
| |
| raw_spin_lock(&last_pool->lock); |
| |
| worker = find_worker_executing_work(last_pool, work); |
| |
| if (worker && worker->current_pwq->wq == wq) { |
| pwq = worker->current_pwq; |
| pool = pwq->pool; |
| WARN_ON_ONCE(pool != last_pool); |
| } else { |
| /* meh... not running there, queue here */ |
| raw_spin_unlock(&last_pool->lock); |
| raw_spin_lock(&pool->lock); |
| } |
| } else { |
| raw_spin_lock(&pool->lock); |
| } |
| |
| /* |
| * pwq is determined and locked. For unbound pools, we could have raced |
| * with pwq release and it could already be dead. If its refcnt is zero, |
| * repeat pwq selection. Note that unbound pwqs never die without |
| * another pwq replacing it in cpu_pwq or while work items are executing |
| * on it, so the retrying is guaranteed to make forward-progress. |
| */ |
| if (unlikely(!pwq->refcnt)) { |
| if (wq->flags & WQ_UNBOUND) { |
| raw_spin_unlock(&pool->lock); |
| cpu_relax(); |
| goto retry; |
| } |
| /* oops */ |
| WARN_ONCE(true, "workqueue: per-cpu pwq for %s on cpu%d has 0 refcnt", |
| wq->name, cpu); |
| } |
| |
| /* pwq determined, queue */ |
| trace_workqueue_queue_work(req_cpu, pwq, work); |
| |
| if (WARN_ON(!list_empty(&work->entry))) |
| goto out; |
| |
| pwq->nr_in_flight[pwq->work_color]++; |
| work_flags = work_color_to_flags(pwq->work_color); |
| |
| if (likely(pwq->nr_active < pwq->max_active)) { |
| if (list_empty(&pool->worklist)) |
| pool->watchdog_ts = jiffies; |
| |
| trace_workqueue_activate_work(work); |
| pwq->nr_active++; |
| insert_work(pwq, work, &pool->worklist, work_flags); |
| kick_pool(pool); |
| } else { |
| work_flags |= WORK_STRUCT_INACTIVE; |
| insert_work(pwq, work, &pwq->inactive_works, work_flags); |
| } |
| |
| out: |
| raw_spin_unlock(&pool->lock); |
| rcu_read_unlock(); |
| } |
| |
| /** |
| * queue_work_on - queue work on specific cpu |
| * @cpu: CPU number to execute work on |
| * @wq: workqueue to use |
| * @work: work to queue |
| * |
| * We queue the work to a specific CPU, the caller must ensure it |
| * can't go away. Callers that fail to ensure that the specified |
| * CPU cannot go away will execute on a randomly chosen CPU. |
| * But note well that callers specifying a CPU that never has been |
| * online will get a splat. |
| * |
| * Return: %false if @work was already on a queue, %true otherwise. |
| */ |
| bool queue_work_on(int cpu, struct workqueue_struct *wq, |
| struct work_struct *work) |
| { |
| bool ret = false; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| |
| if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
| __queue_work(cpu, wq, work); |
| ret = true; |
| } |
| |
| local_irq_restore(flags); |
| return ret; |
| } |
| EXPORT_SYMBOL(queue_work_on); |
| |
| /** |
| * select_numa_node_cpu - Select a CPU based on NUMA node |
| * @node: NUMA node ID that we want to select a CPU from |
| * |
| * This function will attempt to find a "random" cpu available on a given |
| * node. If there are no CPUs available on the given node it will return |
| * WORK_CPU_UNBOUND indicating that we should just schedule to any |
| * available CPU if we need to schedule this work. |
| */ |
| static int select_numa_node_cpu(int node) |
| { |
| int cpu; |
| |
| /* Delay binding to CPU if node is not valid or online */ |
| if (node < 0 || node >= MAX_NUMNODES || !node_online(node)) |
| return WORK_CPU_UNBOUND; |
| |
| /* Use local node/cpu if we are already there */ |
| cpu = raw_smp_processor_id(); |
| if (node == cpu_to_node(cpu)) |
| return cpu; |
| |
| /* Use "random" otherwise know as "first" online CPU of node */ |
| cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask); |
| |
| /* If CPU is valid return that, otherwise just defer */ |
| return cpu < nr_cpu_ids ? cpu : WORK_CPU_UNBOUND; |
| } |
| |
| /** |
| * queue_work_node - queue work on a "random" cpu for a given NUMA node |
| * @node: NUMA node that we are targeting the work for |
| * @wq: workqueue to use |
| * @work: work to queue |
| * |
| * We queue the work to a "random" CPU within a given NUMA node. The basic |
| * idea here is to provide a way to somehow associate work with a given |
| * NUMA node. |
| * |
| * This function will only make a best effort attempt at getting this onto |
| * the right NUMA node. If no node is requested or the requested node is |
| * offline then we just fall back to standard queue_work behavior. |
| * |
| * Currently the "random" CPU ends up being the first available CPU in the |
| * intersection of cpu_online_mask and the cpumask of the node, unless we |
| * are running on the node. In that case we just use the current CPU. |
| * |
| * Return: %false if @work was already on a queue, %true otherwise. |
| */ |
| bool queue_work_node(int node, struct workqueue_struct *wq, |
| struct work_struct *work) |
| { |
| unsigned long flags; |
| bool ret = false; |
| |
| /* |
| * This current implementation is specific to unbound workqueues. |
| * Specifically we only return the first available CPU for a given |
| * node instead of cycling through individual CPUs within the node. |
| * |
| * If this is used with a per-cpu workqueue then the logic in |
| * workqueue_select_cpu_near would need to be updated to allow for |
| * some round robin type logic. |
| */ |
| WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)); |
| |
| local_irq_save(flags); |
| |
| if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
| int cpu = select_numa_node_cpu(node); |
| |
| __queue_work(cpu, wq, work); |
| ret = true; |
| } |
| |
| local_irq_restore(flags); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(queue_work_node); |
| |
| void delayed_work_timer_fn(struct timer_list *t) |
| { |
| struct delayed_work *dwork = from_timer(dwork, t, timer); |
| |
| /* should have been called from irqsafe timer with irq already off */ |
| __queue_work(dwork->cpu, dwork->wq, &dwork->work); |
| } |
| EXPORT_SYMBOL(delayed_work_timer_fn); |
| |
| static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, |
| struct delayed_work *dwork, unsigned long delay) |
| { |
| struct timer_list *timer = &dwork->timer; |
| struct work_struct *work = &dwork->work; |
| |
| WARN_ON_ONCE(!wq); |
| WARN_ON_ONCE(timer->function != delayed_work_timer_fn); |
| WARN_ON_ONCE(timer_pending(timer)); |
| WARN_ON_ONCE(!list_empty(&work->entry)); |
| |
| /* |
| * If @delay is 0, queue @dwork->work immediately. This is for |
| * both optimization and correctness. The earliest @timer can |
| * expire is on the closest next tick and delayed_work users depend |
| * on that there's no such delay when @delay is 0. |
| */ |
| if (!delay) { |
| __queue_work(cpu, wq, &dwork->work); |
| return; |
| } |
| |
| dwork->wq = wq; |
| dwork->cpu = cpu; |
| timer->expires = jiffies + delay; |
| |
| if (unlikely(cpu != WORK_CPU_UNBOUND)) |
| add_timer_on(timer, cpu); |
| else |
| add_timer(timer); |
| } |
| |
| /** |
| * queue_delayed_work_on - queue work on specific CPU after delay |
| * @cpu: CPU number to execute work on |
| * @wq: workqueue to use |
| * @dwork: work to queue |
| * @delay: number of jiffies to wait before queueing |
| * |
| * Return: %false if @work was already on a queue, %true otherwise. If |
| * @delay is zero and @dwork is idle, it will be scheduled for immediate |
| * execution. |
| */ |
| bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
| struct delayed_work *dwork, unsigned long delay) |
| { |
| struct work_struct *work = &dwork->work; |
| bool ret = false; |
| unsigned long flags; |
| |
| /* read the comment in __queue_work() */ |
| local_irq_save(flags); |
| |
| if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
| __queue_delayed_work(cpu, wq, dwork, delay); |
| ret = true; |
| } |
| |
| local_irq_restore(flags); |
| return ret; |
| } |
| EXPORT_SYMBOL(queue_delayed_work_on); |
| |
| /** |
| * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU |
| * @cpu: CPU number to execute work on |
| * @wq: workqueue to use |
| * @dwork: work to queue |
| * @delay: number of jiffies to wait before queueing |
| * |
| * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise, |
| * modify @dwork's timer so that it expires after @delay. If @delay is |
| * zero, @work is guaranteed to be scheduled immediately regardless of its |
| * current state. |
| * |
| * Return: %false if @dwork was idle and queued, %true if @dwork was |
| * pending and its timer was modified. |
| * |
| * This function is safe to call from any context including IRQ handler. |
| * See try_to_grab_pending() for details. |
| */ |
| bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, |
| struct delayed_work *dwork, unsigned long delay) |
| { |
| unsigned long flags; |
| int ret; |
| |
| do { |
| ret = try_to_grab_pending(&dwork->work, true, &flags); |
| } while (unlikely(ret == -EAGAIN)); |
| |
| if (likely(ret >= 0)) { |
| __queue_delayed_work(cpu, wq, dwork, delay); |
| local_irq_restore(flags); |
| } |
| |
| /* -ENOENT from try_to_grab_pending() becomes %true */ |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(mod_delayed_work_on); |
| |
| static void rcu_work_rcufn(struct rcu_head *rcu) |
| { |
| struct rcu_work *rwork = container_of(rcu, struct rcu_work, rcu); |
| |
| /* read the comment in __queue_work() */ |
| local_irq_disable(); |
| __queue_work(WORK_CPU_UNBOUND, rwork->wq, &rwork->work); |
| local_irq_enable(); |
| } |
| |
| /** |
| * queue_rcu_work - queue work after a RCU grace period |
| * @wq: workqueue to use |
| * @rwork: work to queue |
| * |
| * Return: %false if @rwork was already pending, %true otherwise. Note |
| * that a full RCU grace period is guaranteed only after a %true return. |
| * While @rwork is guaranteed to be executed after a %false return, the |
| * execution may happen before a full RCU grace period has passed. |
| */ |
| bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork) |
| { |
| struct work_struct *work = &rwork->work; |
| |
| if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
| rwork->wq = wq; |
| call_rcu_hurry(&rwork->rcu, rcu_work_rcufn); |
| return true; |
| } |
| |
| return false; |
| } |
| EXPORT_SYMBOL(queue_rcu_work); |
| |
| static struct worker *alloc_worker(int node) |
| { |
| struct worker *worker; |
| |
| worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node); |
| if (worker) { |
| INIT_LIST_HEAD(&worker->entry); |
| INIT_LIST_HEAD(&worker->scheduled); |
| INIT_LIST_HEAD(&worker->node); |
| /* on creation a worker is in !idle && prep state */ |
| worker->flags = WORKER_PREP; |
| } |
| return worker; |
| } |
| |
| static cpumask_t *pool_allowed_cpus(struct worker_pool *pool) |
| { |
| if (pool->cpu < 0 && pool->attrs->affn_strict) |
| return pool->attrs->__pod_cpumask; |
| else |
| return pool->attrs->cpumask; |
| } |
| |
| /** |
| * worker_attach_to_pool() - attach a worker to a pool |
| * @worker: worker to be attached |
| * @pool: the target pool |
| * |
| * Attach @worker to @pool. Once attached, the %WORKER_UNBOUND flag and |
| * cpu-binding of @worker are kept coordinated with the pool across |
| * cpu-[un]hotplugs. |
| */ |
| static void worker_attach_to_pool(struct worker *worker, |
| struct worker_pool *pool) |
| { |
| mutex_lock(&wq_pool_attach_mutex); |
| |
| /* |
| * The wq_pool_attach_mutex ensures %POOL_DISASSOCIATED remains |
| * stable across this function. See the comments above the flag |
| * definition for details. |
| */ |
| if (pool->flags & POOL_DISASSOCIATED) |
| worker->flags |= WORKER_UNBOUND; |
| else |
| kthread_set_per_cpu(worker->task, pool->cpu); |
| |
| if (worker->rescue_wq) |
| set_cpus_allowed_ptr(worker->task, pool_allowed_cpus(pool)); |
| |
| list_add_tail(&worker->node, &pool->workers); |
| worker->pool = pool; |
| |
| mutex_unlock(&wq_pool_attach_mutex); |
| } |
| |
| /** |
| * worker_detach_from_pool() - detach a worker from its pool |
| * @worker: worker which is attached to its pool |
| * |
| * Undo the attaching which had been done in worker_attach_to_pool(). The |
| * caller worker shouldn't access to the pool after detached except it has |
| * other reference to the pool. |
| */ |
| static void worker_detach_from_pool(struct worker *worker) |
| { |
| struct worker_pool *pool = worker->pool; |
| struct completion *detach_completion = NULL; |
| |
| mutex_lock(&wq_pool_attach_mutex); |
| |
| kthread_set_per_cpu(worker->task, -1); |
| list_del(&worker->node); |
| worker->pool = NULL; |
| |
| if (list_empty(&pool->workers) && list_empty(&pool->dying_workers)) |
| detach_completion = pool->detach_completion; |
| mutex_unlock(&wq_pool_attach_mutex); |
| |
| /* clear leftover flags without pool->lock after it is detached */ |
| worker->flags &= ~(WORKER_UNBOUND | WORKER_REBOUND); |
| |
| if (detach_completion) |
| complete(detach_completion); |
| } |
| |
| /** |
| * create_worker - create a new workqueue worker |
| * @pool: pool the new worker will belong to |
| * |
| * Create and start a new worker which is attached to @pool. |
| * |
| * CONTEXT: |
| * Might sleep. Does GFP_KERNEL allocations. |
| * |
| * Return: |
| * Pointer to the newly created worker. |
| */ |
| static struct worker *create_worker(struct worker_pool *pool) |
| { |
| struct worker *worker; |
| int id; |
| char id_buf[23]; |
| |
| /* ID is needed to determine kthread name */ |
| id = ida_alloc(&pool->worker_ida, GFP_KERNEL); |
| if (id < 0) { |
| pr_err_once("workqueue: Failed to allocate a worker ID: %pe\n", |
| ERR_PTR(id)); |
| return NULL; |
| } |
| |
| worker = alloc_worker(pool->node); |
| if (!worker) { |
| pr_err_once("workqueue: Failed to allocate a worker\n"); |
| goto fail; |
| } |
| |
| worker->id = id; |
| |
| if (pool->cpu >= 0) |
| snprintf(id_buf, sizeof(id_buf), "%d:%d%s", pool->cpu, id, |
| pool->attrs->nice < 0 ? "H" : ""); |
| else |
| snprintf(id_buf, sizeof(id_buf), "u%d:%d", pool->id, id); |
| |
| worker->task = kthread_create_on_node(worker_thread, worker, pool->node, |
| "kworker/%s", id_buf); |
| if (IS_ERR(worker->task)) { |
| if (PTR_ERR(worker->task) == -EINTR) { |
| pr_err("workqueue: Interrupted when creating a worker thread \"kworker/%s\"\n", |
| id_buf); |
| } else { |
| pr_err_once("workqueue: Failed to create a worker thread: %pe", |
| worker->task); |
| } |
| goto fail; |
| } |
| |
| set_user_nice(worker->task, pool->attrs->nice); |
| kthread_bind_mask(worker->task, pool_allowed_cpus(pool)); |
| |
| /* successful, attach the worker to the pool */ |
| worker_attach_to_pool(worker, pool); |
| |
| /* start the newly created worker */ |
| raw_spin_lock_irq(&pool->lock); |
| |
| worker->pool->nr_workers++; |
| worker_enter_idle(worker); |
| kick_pool(pool); |
| |
| /* |
| * @worker is waiting on a completion in kthread() and will trigger hung |
| * check if not woken up soon. As kick_pool() might not have waken it |
| * up, wake it up explicitly once more. |
| */ |
| wake_up_process(worker->task); |
| |
| raw_spin_unlock_irq(&pool->lock); |
| |
| return worker; |
| |
| fail: |
| ida_free(&pool->worker_ida, id); |
| kfree(worker); |
| return NULL; |
| } |
| |
| static void unbind_worker(struct worker *worker) |
| { |
| lockdep_assert_held(&wq_pool_attach_mutex); |
| |
| kthread_set_per_cpu(worker->task, -1); |
| if (cpumask_intersects(wq_unbound_cpumask, cpu_active_mask)) |
| WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, wq_unbound_cpumask) < 0); |
| else |
| WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0); |
| } |
| |
| static void wake_dying_workers(struct list_head *cull_list) |
| { |
| struct worker *worker, *tmp; |
| |
| list_for_each_entry_safe(worker, tmp, cull_list, entry) { |
| list_del_init(&worker->entry); |
| unbind_worker(worker); |
| /* |
| * If the worker was somehow already running, then it had to be |
| * in pool->idle_list when set_worker_dying() happened or we |
| * wouldn't have gotten here. |
| * |
| * Thus, the worker must either have observed the WORKER_DIE |
| * flag, or have set its state to TASK_IDLE. Either way, the |
| * below will be observed by the worker and is safe to do |
| * outside of pool->lock. |
| */ |
| wake_up_process(worker->task); |
| } |
| } |
| |
| /** |
| * set_worker_dying - Tag a worker for destruction |
| * @worker: worker to be destroyed |
| * @list: transfer worker away from its pool->idle_list and into list |
| * |
| * Tag @worker for destruction and adjust @pool stats accordingly. The worker |
| * should be idle. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(pool->lock). |
| */ |
| static void set_worker_dying(struct worker *worker, struct list_head *list) |
| { |
| struct worker_pool *pool = worker->pool; |
| |
| lockdep_assert_held(&pool->lock); |
| lockdep_assert_held(&wq_pool_attach_mutex); |
| |
| /* sanity check frenzy */ |
| if (WARN_ON(worker->current_work) || |
| WARN_ON(!list_empty(&worker->scheduled)) || |
| WARN_ON(!(worker->flags & WORKER_IDLE))) |
| return; |
| |
| pool->nr_workers--; |
| pool->nr_idle--; |
| |
| worker->flags |= WORKER_DIE; |
| |
| list_move(&worker->entry, list); |
| list_move(&worker->node, &pool->dying_workers); |
| } |
| |
| /** |
| * idle_worker_timeout - check if some idle workers can now be deleted. |
| * @t: The pool's idle_timer that just expired |
| * |
| * The timer is armed in worker_enter_idle(). Note that it isn't disarmed in |
| * worker_leave_idle(), as a worker flicking between idle and active while its |
| * pool is at the too_many_workers() tipping point would cause too much timer |
| * housekeeping overhead. Since IDLE_WORKER_TIMEOUT is long enough, we just let |
| * it expire and re-evaluate things from there. |
| */ |
| static void idle_worker_timeout(struct timer_list *t) |
| { |
| struct worker_pool *pool = from_timer(pool, t, idle_timer); |
| bool do_cull = false; |
| |
| if (work_pending(&pool->idle_cull_work)) |
| return; |
| |
| raw_spin_lock_irq(&pool->lock); |
| |
| if (too_many_workers(pool)) { |
| struct worker *worker; |
| unsigned long expires; |
| |
| /* idle_list is kept in LIFO order, check the last one */ |
| worker = list_entry(pool->idle_list.prev, struct worker, entry); |
| expires = worker->last_active + IDLE_WORKER_TIMEOUT; |
| do_cull = !time_before(jiffies, expires); |
| |
| if (!do_cull) |
| mod_timer(&pool->idle_timer, expires); |
| } |
| raw_spin_unlock_irq(&pool->lock); |
| |
| if (do_cull) |
| queue_work(system_unbound_wq, &pool->idle_cull_work); |
| } |
| |
| /** |
| * idle_cull_fn - cull workers that have been idle for too long. |
| * @work: the pool's work for handling these idle workers |
| * |
| * This goes through a pool's idle workers and gets rid of those that have been |
| * idle for at least IDLE_WORKER_TIMEOUT seconds. |
| * |
| * We don't want to disturb isolated CPUs because of a pcpu kworker being |
| * culled, so this also resets worker affinity. This requires a sleepable |
| * context, hence the split between timer callback and work item. |
| */ |
| static void idle_cull_fn(struct work_struct *work) |
| { |
| struct worker_pool *pool = container_of(work, struct worker_pool, idle_cull_work); |
| LIST_HEAD(cull_list); |
| |
| /* |
| * Grabbing wq_pool_attach_mutex here ensures an already-running worker |
| * cannot proceed beyong worker_detach_from_pool() in its self-destruct |
| * path. This is required as a previously-preempted worker could run after |
| * set_worker_dying() has happened but before wake_dying_workers() did. |
| */ |
| mutex_lock(&wq_pool_attach_mutex); |
| raw_spin_lock_irq(&pool->lock); |
| |
| while (too_many_workers(pool)) { |
| struct worker *worker; |
| unsigned long expires; |
| |
| worker = list_entry(pool->idle_list.prev, struct worker, entry); |
| expires = worker->last_active + IDLE_WORKER_TIMEOUT; |
| |
| if (time_before(jiffies, expires)) { |
| mod_timer(&pool->idle_timer, expires); |
| break; |
| } |
| |
| set_worker_dying(worker, &cull_list); |
| } |
| |
| raw_spin_unlock_irq(&pool->lock); |
| wake_dying_workers(&cull_list); |
| mutex_unlock(&wq_pool_attach_mutex); |
| } |
| |
| static void send_mayday(struct work_struct *work) |
| { |
| struct pool_workqueue *pwq = get_work_pwq(work); |
| struct workqueue_struct *wq = pwq->wq; |
| |
| lockdep_assert_held(&wq_mayday_lock); |
| |
| if (!wq->rescuer) |
| return; |
| |
| /* mayday mayday mayday */ |
| if (list_empty(&pwq->mayday_node)) { |
| /* |
| * If @pwq is for an unbound wq, its base ref may be put at |
| * any time due to an attribute change. Pin @pwq until the |
| * rescuer is done with it. |
| */ |
| get_pwq(pwq); |
| list_add_tail(&pwq->mayday_node, &wq->maydays); |
| wake_up_process(wq->rescuer->task); |
| pwq->stats[PWQ_STAT_MAYDAY]++; |
| } |
| } |
| |
| static void pool_mayday_timeout(struct timer_list *t) |
| { |
| struct worker_pool *pool = from_timer(pool, t, mayday_timer); |
| struct work_struct *work; |
| |
| raw_spin_lock_irq(&pool->lock); |
| raw_spin_lock(&wq_mayday_lock); /* for wq->maydays */ |
| |
| if (need_to_create_worker(pool)) { |
| /* |
| * We've been trying to create a new worker but |
| * haven't been successful. We might be hitting an |
| * allocation deadlock. Send distress signals to |
| * rescuers. |
| */ |
| list_for_each_entry(work, &pool->worklist, entry) |
| send_mayday(work); |
| } |
| |
| raw_spin_unlock(&wq_mayday_lock); |
| raw_spin_unlock_irq(&pool->lock); |
| |
| mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); |
| } |
| |
| /** |
| * maybe_create_worker - create a new worker if necessary |
| * @pool: pool to create a new worker for |
| * |
| * Create a new worker for @pool if necessary. @pool is guaranteed to |
| * have at least one idle worker on return from this function. If |
| * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is |
| * sent to all rescuers with works scheduled on @pool to resolve |
| * possible allocation deadlock. |
| * |
| * On return, need_to_create_worker() is guaranteed to be %false and |
| * may_start_working() %true. |
| * |
| * LOCKING: |
| * raw_spin_lock_irq(pool->lock) which may be released and regrabbed |
| * multiple times. Does GFP_KERNEL allocations. Called only from |
| * manager. |
| */ |
| static void maybe_create_worker(struct worker_pool *pool) |
| __releases(&pool->lock) |
| __acquires(&pool->lock) |
| { |
| restart: |
| raw_spin_unlock_irq(&pool->lock); |
| |
| /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ |
| mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); |
| |
| while (true) { |
| if (create_worker(pool) || !need_to_create_worker(pool)) |
| break; |
| |
| schedule_timeout_interruptible(CREATE_COOLDOWN); |
| |
| if (!need_to_create_worker(pool)) |
| break; |
| } |
| |
| del_timer_sync(&pool->mayday_timer); |
| raw_spin_lock_irq(&pool->lock); |
| /* |
| * This is necessary even after a new worker was just successfully |
| * created as @pool->lock was dropped and the new worker might have |
| * already become busy. |
| */ |
| if (need_to_create_worker(pool)) |
| goto restart; |
| } |
| |
| /** |
| * manage_workers - manage worker pool |
| * @worker: self |
| * |
| * Assume the manager role and manage the worker pool @worker belongs |
| * to. At any given time, there can be only zero or one manager per |
| * pool. The exclusion is handled automatically by this function. |
| * |
| * The caller can safely start processing works on false return. On |
| * true return, it's guaranteed that need_to_create_worker() is false |
| * and may_start_working() is true. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(pool->lock) which may be released and regrabbed |
| * multiple times. Does GFP_KERNEL allocations. |
| * |
| * Return: |
| * %false if the pool doesn't need management and the caller can safely |
| * start processing works, %true if management function was performed and |
| * the conditions that the caller verified before calling the function may |
| * no longer be true. |
| */ |
| static bool manage_workers(struct worker *worker) |
| { |
| struct worker_pool *pool = worker->pool; |
| |
| if (pool->flags & POOL_MANAGER_ACTIVE) |
| return false; |
| |
| pool->flags |= POOL_MANAGER_ACTIVE; |
| pool->manager = worker; |
| |
| maybe_create_worker(pool); |
| |
| pool->manager = NULL; |
| pool->flags &= ~POOL_MANAGER_ACTIVE; |
| rcuwait_wake_up(&manager_wait); |
| return true; |
| } |
| |
| /** |
| * process_one_work - process single work |
| * @worker: self |
| * @work: work to process |
| * |
| * Process @work. This function contains all the logics necessary to |
| * process a single work including synchronization against and |
| * interaction with other workers on the same cpu, queueing and |
| * flushing. As long as context requirement is met, any worker can |
| * call this function to process a work. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(pool->lock) which is released and regrabbed. |
| */ |
| static void process_one_work(struct worker *worker, struct work_struct *work) |
| __releases(&pool->lock) |
| __acquires(&pool->lock) |
| { |
| struct pool_workqueue *pwq = get_work_pwq(work); |
| struct worker_pool *pool = worker->pool; |
| unsigned long work_data; |
| #ifdef CONFIG_LOCKDEP |
| /* |
| * It is permissible to free the struct work_struct from |
| * inside the function that is called from it, this we need to |
| * take into account for lockdep too. To avoid bogus "held |
| * lock freed" warnings as well as problems when looking into |
| * work->lockdep_map, make a copy and use that here. |
| */ |
| struct lockdep_map lockdep_map; |
| |
| lockdep_copy_map(&lockdep_map, &work->lockdep_map); |
| #endif |
| /* ensure we're on the correct CPU */ |
| WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) && |
| raw_smp_processor_id() != pool->cpu); |
| |
| /* claim and dequeue */ |
| debug_work_deactivate(work); |
| hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work); |
| worker->current_work = work; |
| worker->current_func = work->func; |
| worker->current_pwq = pwq; |
| worker->current_at = worker->task->se.sum_exec_runtime; |
| work_data = *work_data_bits(work); |
| worker->current_color = get_work_color(work_data); |
| |
| /* |
| * Record wq name for cmdline and debug reporting, may get |
| * overridden through set_worker_desc(). |
| */ |
| strscpy(worker->desc, pwq->wq->name, WORKER_DESC_LEN); |
| |
| list_del_init(&work->entry); |
| |
| /* |
| * CPU intensive works don't participate in concurrency management. |
| * They're the scheduler's responsibility. This takes @worker out |
| * of concurrency management and the next code block will chain |
| * execution of the pending work items. |
| */ |
| if (unlikely(pwq->wq->flags & WQ_CPU_INTENSIVE)) |
| worker_set_flags(worker, WORKER_CPU_INTENSIVE); |
| |
| /* |
| * Kick @pool if necessary. It's always noop for per-cpu worker pools |
| * since nr_running would always be >= 1 at this point. This is used to |
| * chain execution of the pending work items for WORKER_NOT_RUNNING |
| * workers such as the UNBOUND and CPU_INTENSIVE ones. |
| */ |
| kick_pool(pool); |
| |
| /* |
| * Record the last pool and clear PENDING which should be the last |
| * update to @work. Also, do this inside @pool->lock so that |
| * PENDING and queued state changes happen together while IRQ is |
| * disabled. |
| */ |
| set_work_pool_and_clear_pending(work, pool->id); |
| |
| pwq->stats[PWQ_STAT_STARTED]++; |
| raw_spin_unlock_irq(&pool->lock); |
| |
| lock_map_acquire(&pwq->wq->lockdep_map); |
| lock_map_acquire(&lockdep_map); |
| /* |
| * Strictly speaking we should mark the invariant state without holding |
| * any locks, that is, before these two lock_map_acquire()'s. |
| * |
| * However, that would result in: |
| * |
| * A(W1) |
| * WFC(C) |
| * A(W1) |
| * C(C) |
| * |
| * Which would create W1->C->W1 dependencies, even though there is no |
| * actual deadlock possible. There are two solutions, using a |
| * read-recursive acquire on the work(queue) 'locks', but this will then |
| * hit the lockdep limitation on recursive locks, or simply discard |
| * these locks. |
| * |
| * AFAICT there is no possible deadlock scenario between the |
| * flush_work() and complete() primitives (except for single-threaded |
| * workqueues), so hiding them isn't a problem. |
| */ |
| lockdep_invariant_state(true); |
| trace_workqueue_execute_start(work); |
| worker->current_func(work); |
| /* |
| * While we must be careful to not use "work" after this, the trace |
| * point will only record its address. |
| */ |
| trace_workqueue_execute_end(work, worker->current_func); |
| pwq->stats[PWQ_STAT_COMPLETED]++; |
| lock_map_release(&lockdep_map); |
| lock_map_release(&pwq->wq->lockdep_map); |
| |
| if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { |
| pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n" |
| " last function: %ps\n", |
| current->comm, preempt_count(), task_pid_nr(current), |
| worker->current_func); |
| debug_show_held_locks(current); |
| dump_stack(); |
| } |
| |
| /* |
| * The following prevents a kworker from hogging CPU on !PREEMPTION |
| * kernels, where a requeueing work item waiting for something to |
| * happen could deadlock with stop_machine as such work item could |
| * indefinitely requeue itself while all other CPUs are trapped in |
| * stop_machine. At the same time, report a quiescent RCU state so |
| * the same condition doesn't freeze RCU. |
| */ |
| cond_resched(); |
| |
| raw_spin_lock_irq(&pool->lock); |
| |
| /* |
| * In addition to %WQ_CPU_INTENSIVE, @worker may also have been marked |
| * CPU intensive by wq_worker_tick() if @work hogged CPU longer than |
| * wq_cpu_intensive_thresh_us. Clear it. |
| */ |
| worker_clr_flags(worker, WORKER_CPU_INTENSIVE); |
| |
| /* tag the worker for identification in schedule() */ |
| worker->last_func = worker->current_func; |
| |
| /* we're done with it, release */ |
| hash_del(&worker->hentry); |
| worker->current_work = NULL; |
| worker->current_func = NULL; |
| worker->current_pwq = NULL; |
| worker->current_color = INT_MAX; |
| pwq_dec_nr_in_flight(pwq, work_data); |
| } |
| |
| /** |
| * process_scheduled_works - process scheduled works |
| * @worker: self |
| * |
| * Process all scheduled works. Please note that the scheduled list |
| * may change while processing a work, so this function repeatedly |
| * fetches a work from the top and executes it. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(pool->lock) which may be released and regrabbed |
| * multiple times. |
| */ |
| static void process_scheduled_works(struct worker *worker) |
| { |
| struct work_struct *work; |
| bool first = true; |
| |
| while ((work = list_first_entry_or_null(&worker->scheduled, |
| struct work_struct, entry))) { |
| if (first) { |
| worker->pool->watchdog_ts = jiffies; |
| first = false; |
| } |
| process_one_work(worker, work); |
| } |
| } |
| |
| static void set_pf_worker(bool val) |
| { |
| mutex_lock(&wq_pool_attach_mutex); |
| if (val) |
| current->flags |= PF_WQ_WORKER; |
| else |
| current->flags &= ~PF_WQ_WORKER; |
| mutex_unlock(&wq_pool_attach_mutex); |
| } |
| |
| /** |
| * worker_thread - the worker thread function |
| * @__worker: self |
| * |
| * The worker thread function. All workers belong to a worker_pool - |
| * either a per-cpu one or dynamic unbound one. These workers process all |
| * work items regardless of their specific target workqueue. The only |
| * exception is work items which belong to workqueues with a rescuer which |
| * will be explained in rescuer_thread(). |
| * |
| * Return: 0 |
| */ |
| static int worker_thread(void *__worker) |
| { |
| struct worker *worker = __worker; |
| struct worker_pool *pool = worker->pool; |
| |
| /* tell the scheduler that this is a workqueue worker */ |
| set_pf_worker(true); |
| woke_up: |
| raw_spin_lock_irq(&pool->lock); |
| |
| /* am I supposed to die? */ |
| if (unlikely(worker->flags & WORKER_DIE)) { |
| raw_spin_unlock_irq(&pool->lock); |
| set_pf_worker(false); |
| |
| set_task_comm(worker->task, "kworker/dying"); |
| ida_free(&pool->worker_ida, worker->id); |
| worker_detach_from_pool(worker); |
| WARN_ON_ONCE(!list_empty(&worker->entry)); |
| kfree(worker); |
| return 0; |
| } |
| |
| worker_leave_idle(worker); |
| recheck: |
| /* no more worker necessary? */ |
| if (!need_more_worker(pool)) |
| goto sleep; |
| |
| /* do we need to manage? */ |
| if (unlikely(!may_start_working(pool)) && manage_workers(worker)) |
| goto recheck; |
| |
| /* |
| * ->scheduled list can only be filled while a worker is |
| * preparing to process a work or actually processing it. |
| * Make sure nobody diddled with it while I was sleeping. |
| */ |
| WARN_ON_ONCE(!list_empty(&worker->scheduled)); |
| |
| /* |
| * Finish PREP stage. We're guaranteed to have at least one idle |
| * worker or that someone else has already assumed the manager |
| * role. This is where @worker starts participating in concurrency |
| * management if applicable and concurrency management is restored |
| * after being rebound. See rebind_workers() for details. |
| */ |
| worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND); |
| |
| do { |
| struct work_struct *work = |
| list_first_entry(&pool->worklist, |
| struct work_struct, entry); |
| |
| if (assign_work(work, worker, NULL)) |
| process_scheduled_works(worker); |
| } while (keep_working(pool)); |
| |
| worker_set_flags(worker, WORKER_PREP); |
| sleep: |
| /* |
| * pool->lock is held and there's no work to process and no need to |
| * manage, sleep. Workers are woken up only while holding |
| * pool->lock or from local cpu, so setting the current state |
| * before releasing pool->lock is enough to prevent losing any |
| * event. |
| */ |
| worker_enter_idle(worker); |
| __set_current_state(TASK_IDLE); |
| raw_spin_unlock_irq(&pool->lock); |
| schedule(); |
| goto woke_up; |
| } |
| |
| /** |
| * rescuer_thread - the rescuer thread function |
| * @__rescuer: self |
| * |
| * Workqueue rescuer thread function. There's one rescuer for each |
| * workqueue which has WQ_MEM_RECLAIM set. |
| * |
| * Regular work processing on a pool may block trying to create a new |
| * worker which uses GFP_KERNEL allocation which has slight chance of |
| * developing into deadlock if some works currently on the same queue |
| * need to be processed to satisfy the GFP_KERNEL allocation. This is |
| * the problem rescuer solves. |
| * |
| * When such condition is possible, the pool summons rescuers of all |
| * workqueues which have works queued on the pool and let them process |
| * those works so that forward progress can be guaranteed. |
| * |
| * This should happen rarely. |
| * |
| * Return: 0 |
| */ |
| static int rescuer_thread(void *__rescuer) |
| { |
| struct worker *rescuer = __rescuer; |
| struct workqueue_struct *wq = rescuer->rescue_wq; |
| bool should_stop; |
| |
| set_user_nice(current, RESCUER_NICE_LEVEL); |
| |
| /* |
| * Mark rescuer as worker too. As WORKER_PREP is never cleared, it |
| * doesn't participate in concurrency management. |
| */ |
| set_pf_worker(true); |
| repeat: |
| set_current_state(TASK_IDLE); |
| |
| /* |
| * By the time the rescuer is requested to stop, the workqueue |
| * shouldn't have any work pending, but @wq->maydays may still have |
| * pwq(s) queued. This can happen by non-rescuer workers consuming |
| * all the work items before the rescuer got to them. Go through |
| * @wq->maydays processing before acting on should_stop so that the |
| * list is always empty on exit. |
| */ |
| should_stop = kthread_should_stop(); |
| |
| /* see whether any pwq is asking for help */ |
| raw_spin_lock_irq(&wq_mayday_lock); |
| |
| while (!list_empty(&wq->maydays)) { |
| struct pool_workqueue *pwq = list_first_entry(&wq->maydays, |
| struct pool_workqueue, mayday_node); |
| struct worker_pool *pool = pwq->pool; |
| struct work_struct *work, *n; |
| |
| __set_current_state(TASK_RUNNING); |
| list_del_init(&pwq->mayday_node); |
| |
| raw_spin_unlock_irq(&wq_mayday_lock); |
| |
| worker_attach_to_pool(rescuer, pool); |
| |
| raw_spin_lock_irq(&pool->lock); |
| |
| /* |
| * Slurp in all works issued via this workqueue and |
| * process'em. |
| */ |
| WARN_ON_ONCE(!list_empty(&rescuer->scheduled)); |
| list_for_each_entry_safe(work, n, &pool->worklist, entry) { |
| if (get_work_pwq(work) == pwq && |
| assign_work(work, rescuer, &n)) |
| pwq->stats[PWQ_STAT_RESCUED]++; |
| } |
| |
| if (!list_empty(&rescuer->scheduled)) { |
| process_scheduled_works(rescuer); |
| |
| /* |
| * The above execution of rescued work items could |
| * have created more to rescue through |
| * pwq_activate_first_inactive() or chained |
| * queueing. Let's put @pwq back on mayday list so |
| * that such back-to-back work items, which may be |
| * being used to relieve memory pressure, don't |
| * incur MAYDAY_INTERVAL delay inbetween. |
| */ |
| if (pwq->nr_active && need_to_create_worker(pool)) { |
| raw_spin_lock(&wq_mayday_lock); |
| /* |
| * Queue iff we aren't racing destruction |
| * and somebody else hasn't queued it already. |
| */ |
| if (wq->rescuer && list_empty(&pwq->mayday_node)) { |
| get_pwq(pwq); |
| list_add_tail(&pwq->mayday_node, &wq->maydays); |
| } |
| raw_spin_unlock(&wq_mayday_lock); |
| } |
| } |
| |
| /* |
| * Put the reference grabbed by send_mayday(). @pool won't |
| * go away while we're still attached to it. |
| */ |
| put_pwq(pwq); |
| |
| /* |
| * Leave this pool. Notify regular workers; otherwise, we end up |
| * with 0 concurrency and stalling the execution. |
| */ |
| kick_pool(pool); |
| |
| raw_spin_unlock_irq(&pool->lock); |
| |
| worker_detach_from_pool(rescuer); |
| |
| raw_spin_lock_irq(&wq_mayday_lock); |
| } |
| |
| raw_spin_unlock_irq(&wq_mayday_lock); |
| |
| if (should_stop) { |
| __set_current_state(TASK_RUNNING); |
| set_pf_worker(false); |
| return 0; |
| } |
| |
| /* rescuers should never participate in concurrency management */ |
| WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING)); |
| schedule(); |
| goto repeat; |
| } |
| |
| /** |
| * check_flush_dependency - check for flush dependency sanity |
| * @target_wq: workqueue being flushed |
| * @target_work: work item being flushed (NULL for workqueue flushes) |
| * |
| * %current is trying to flush the whole @target_wq or @target_work on it. |
| * If @target_wq doesn't have %WQ_MEM_RECLAIM, verify that %current is not |
| * reclaiming memory or running on a workqueue which doesn't have |
| * %WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to |
| * a deadlock. |
| */ |
| static void check_flush_dependency(struct workqueue_struct *target_wq, |
| struct work_struct *target_work) |
| { |
| work_func_t target_func = target_work ? target_work->func : NULL; |
| struct worker *worker; |
| |
| if (target_wq->flags & WQ_MEM_RECLAIM) |
| return; |
| |
| worker = current_wq_worker(); |
| |
| WARN_ONCE(current->flags & PF_MEMALLOC, |
| "workqueue: PF_MEMALLOC task %d(%s) is flushing !WQ_MEM_RECLAIM %s:%ps", |
| current->pid, current->comm, target_wq->name, target_func); |
| WARN_ONCE(worker && ((worker->current_pwq->wq->flags & |
| (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM), |
| "workqueue: WQ_MEM_RECLAIM %s:%ps is flushing !WQ_MEM_RECLAIM %s:%ps", |
| worker->current_pwq->wq->name, worker->current_func, |
| target_wq->name, target_func); |
| } |
| |
| struct wq_barrier { |
| struct work_struct work; |
| struct completion done; |
| struct task_struct *task; /* purely informational */ |
| }; |
| |
| static void wq_barrier_func(struct work_struct *work) |
| { |
| struct wq_barrier *barr = container_of(work, struct wq_barrier, work); |
| complete(&barr->done); |
| } |
| |
| /** |
| * insert_wq_barrier - insert a barrier work |
| * @pwq: pwq to insert barrier into |
| * @barr: wq_barrier to insert |
| * @target: target work to attach @barr to |
| * @worker: worker currently executing @target, NULL if @target is not executing |
| * |
| * @barr is linked to @target such that @barr is completed only after |
| * @target finishes execution. Please note that the ordering |
| * guarantee is observed only with respect to @target and on the local |
| * cpu. |
| * |
| * Currently, a queued barrier can't be canceled. This is because |
| * try_to_grab_pending() can't determine whether the work to be |
| * grabbed is at the head of the queue and thus can't clear LINKED |
| * flag of the previous work while there must be a valid next work |
| * after a work with LINKED flag set. |
| * |
| * Note that when @worker is non-NULL, @target may be modified |
| * underneath us, so we can't reliably determine pwq from @target. |
| * |
| * CONTEXT: |
| * raw_spin_lock_irq(pool->lock). |
| */ |
| static void insert_wq_barrier(struct pool_workqueue *pwq, |
| struct wq_barrier *barr, |
| struct work_struct *target, struct worker *worker) |
| { |
| unsigned int work_flags = 0; |
| unsigned int work_color; |
| struct list_head *head; |
| |
| /* |
| * debugobject calls are safe here even with pool->lock locked |
| * as we know for sure that this will not trigger any of the |
| * checks and call back into the fixup functions where we |
| * might deadlock. |
| */ |
| INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); |
| __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); |
| |
| init_completion_map(&barr->done, &target->lockdep_map); |
| |
| barr->task = current; |
| |
| /* The barrier work item does not participate in pwq->nr_active. */ |
| work_flags |= WORK_STRUCT_INACTIVE; |
| |
| /* |
| * If @target is currently being executed, schedule the |
| * barrier to the worker; otherwise, put it after @target. |
| */ |
| if (worker) { |
| head = worker->scheduled.next; |
| work_color = worker->current_color; |
| } else { |
| unsigned long *bits = work_data_bits(target); |
| |
| head = target->entry.next; |
| /* there can already be other linked works, inherit and set */ |
| work_flags |= *bits & WORK_STRUCT_LINKED; |
| work_color = get_work_color(*bits); |
| __set_bit(WORK_STRUCT_LINKED_BIT, bits); |
| } |
| |
| pwq->nr_in_flight[work_color]++; |
| work_flags |= work_color_to_flags(work_color); |
| |
| insert_work(pwq, &barr->work, head, work_flags); |
| } |
| |
| /** |
| * flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing |
| * @wq: workqueue being flushed |
| * @flush_color: new flush color, < 0 for no-op |
| * @work_color: new work color, < 0 for no-op |
| * |
| * Prepare pwqs for workqueue flushing. |
| * |
| * If @flush_color is non-negative, flush_color on all pwqs should be |
| * -1. If no pwq has in-flight commands at the specified color, all |
| * pwq->flush_color's stay at -1 and %false is returned. If any pwq |
| * has in flight commands, its pwq->flush_color is set to |
| * @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq |
| * wakeup logic is armed and %true is returned. |
| * |
| * The caller should have initialized @wq->first_flusher prior to |
| * calling this function with non-negative @flush_color. If |
| * @flush_color is negative, no flush color update is done and %false |
| * is returned. |
| * |
| * If @work_color is non-negative, all pwqs should have the same |
| * work_color which is previous to @work_color and all will be |
| * advanced to @work_color. |
| * |
| * CONTEXT: |
| * mutex_lock(wq->mutex). |
| * |
| * Return: |
| * %true if @flush_color >= 0 and there's something to flush. %false |
| * otherwise. |
| */ |
| static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq, |
| int flush_color, int work_color) |
| { |
| bool wait = false; |
| struct pool_workqueue *pwq; |
| |
| if (flush_color >= 0) { |
| WARN_ON_ONCE(atomic_read(&wq->nr_pwqs_to_flush)); |
| atomic_set(&wq->nr_pwqs_to_flush, 1); |
| } |
| |
| for_each_pwq(pwq, wq) { |
| struct worker_pool *pool = pwq->pool; |
| |
| raw_spin_lock_irq(&pool->lock); |
| |
| if (flush_color >= 0) { |
| WARN_ON_ONCE(pwq->flush_color != -1); |
| |
| if (pwq->nr_in_flight[flush_color]) { |
| pwq->flush_color = flush_color; |
| atomic_inc(&wq->nr_pwqs_to_flush); |
| wait = true; |
| } |
| } |
| |
| if (work_color >= 0) { |
| WARN_ON_ONCE(work_color != work_next_color(pwq->work_color)); |
| pwq->work_color = work_color; |
| } |
| |
| raw_spin_unlock_irq(&pool->lock); |
| } |
| |
| if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush)) |
| complete(&wq->first_flusher->done); |
| |
| return wait; |
| } |
| |
| /** |
| * __flush_workqueue - ensure that any scheduled work has run to completion. |
| * @wq: workqueue to flush |
| * |
| * This function sleeps until all work items which were queued on entry |
| * have finished execution, but it is not livelocked by new incoming ones. |
| */ |
| void __flush_workqueue(struct workqueue_struct *wq) |
| { |
| struct wq_flusher this_flusher = { |
| .list = LIST_HEAD_INIT(this_flusher.list), |
| .flush_color = -1, |
| .done = COMPLETION_INITIALIZER_ONSTACK_MAP(this_flusher.done, wq->lockdep_map), |
| }; |
| int next_color; |
| |
| if (WARN_ON(!wq_online)) |
| return; |
| |
| lock_map_acquire(&wq->lockdep_map); |
| lock_map_release(&wq->lockdep_map); |
| |
| mutex_lock(&wq->mutex); |
| |
| /* |
| * Start-to-wait phase |
| */ |
| next_color = work_next_color(wq->work_color); |
| |
| if (next_color != wq->flush_color) { |
| /* |
| * Color space is not full. The current work_color |
| * becomes our flush_color and work_color is advanced |
| * by one. |
| */ |
| WARN_ON_ONCE(!list_empty(&wq->flusher_overflow)); |
| this_flusher.flush_color = wq->work_color; |
| wq->work_color = next_color; |
| |
| if (!wq->first_flusher) { |
| /* no flush in progress, become the first flusher */ |
| WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color); |
| |
| wq->first_flusher = &this_flusher; |
| |
| if (!flush_workqueue_prep_pwqs(wq, wq->flush_color, |
| wq->work_color)) { |
| /* nothing to flush, done */ |
| wq->flush_color = next_color; |
| wq->first_flusher = NULL; |
| goto out_unlock; |
| } |
| } else { |
| /* wait in queue */ |
| WARN_ON_ONCE(wq->flush_color == this_flusher.flush_color); |
| list_add_tail(&this_flusher.list, &wq->flusher_queue); |
| flush_workqueue_prep_pwqs(wq, -1, wq->work_color); |
| } |
| } else { |
| /* |
| * Oops, color space is full, wait on overflow queue. |
| * The next flush completion will assign us |
| * flush_color and transfer to flusher_queue. |
| */ |
| list_add_tail(&this_flusher.list, &wq->flusher_overflow); |
| } |
| |
| check_flush_dependency(wq, NULL); |
| |
| mutex_unlock(&wq->mutex); |
| |
| wait_for_completion(&this_flusher.done); |
| |
| /* |
| * Wake-up-and-cascade phase |
| * |
| * First flushers are responsible for cascading flushes and |
| * handling overflow. Non-first flushers can simply return. |
| */ |
| if (READ_ONCE(wq->first_flusher) != &this_flusher) |
| return; |
| |
| mutex_lock(&wq->mutex); |
| |
| /* we might have raced, check again with mutex held */ |
| if (wq->first_flusher != &this_flusher) |
| goto out_unlock; |
| |
| WRITE_ONCE(wq->first_flusher, NULL); |
| |
| WARN_ON_ONCE(!list_empty(&this_flusher.list)); |
| WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color); |
| |
| while (true) { |
| struct wq_flusher *next, *tmp; |
| |
| /* complete all the flushers sharing the current flush color */ |
| list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { |
| if (next->flush_color != wq->flush_color) |
| break; |
| list_del_init(&next->list); |
| complete(&next->done); |
| } |
| |
| WARN_ON_ONCE(!list_empty(&wq->flusher_overflow) && |
| wq->flush_color != work_next_color(wq->work_color)); |
| |
| /* this flush_color is finished, advance by one */ |
| wq->flush_color = work_next_color(wq->flush_color); |
| |
| /* one color has been freed, handle overflow queue */ |
| if (!list_empty(&wq->flusher_overflow)) { |
| /* |
| * Assign the same color to all overflowed |
| * flushers, advance work_color and append to |
| * flusher_queue. This is the start-to-wait |
| * phase for these overflowed flushers. |
| */ |
| list_for_each_entry(tmp, &wq->flusher_overflow, list) |
| tmp->flush_color = wq->work_color; |
| |
| wq->work_color = work_next_color(wq->work_color); |
| |
| list_splice_tail_init(&wq->flusher_overflow, |
| &wq->flusher_queue); |
| flush_workqueue_prep_pwqs(wq, -1, wq->work_color); |
| } |
| |
| if (list_empty(&wq->flusher_queue)) { |
| WARN_ON_ONCE(wq->flush_color != wq->work_color); |
| break; |
| } |
| |
| /* |
| * Need to flush more colors. Make the next flusher |
| * the new first flusher and arm pwqs. |
| */ |
| WARN_ON_ONCE(wq->flush_color == wq->work_color); |
| WARN_ON_ONCE(wq->flush_color != next->flush_color); |
| |
| list_del_init(&next->list); |
| wq->first_flusher = next; |
| |
| if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1)) |
| break; |
| |
| /* |
| * Meh... this color is already done, clear first |
| * flusher and repeat cascading. |
| */ |
| wq->first_flusher = NULL; |
| } |
| |
| out_unlock: |
| mutex_unlock(&wq->mutex); |
| } |
| EXPORT_SYMBOL(__flush_workqueue); |
| |
| /** |
| * drain_workqueue - drain a workqueue |
| * @wq: workqueue to drain |
| * |
| * Wait until the workqueue becomes empty. While draining is in progress, |
| * only chain queueing is allowed. IOW, only currently pending or running |
| * work items on @wq can queue further work items on it. @wq is flushed |
| * repeatedly until it becomes empty. The number of flushing is determined |
| * by the depth of chaining and should be relatively short. Whine if it |
| * takes too long. |
| */ |
| void drain_workqueue(struct workqueue_struct *wq) |
| { |
| unsigned int flush_cnt = 0; |
| struct pool_workqueue *pwq; |
| |
| /* |
| * __queue_work() needs to test whether there are drainers, is much |
| * hotter than drain_workqueue() and already looks at @wq->flags. |
| * Use __WQ_DRAINING so that queue doesn't have to check nr_drainers. |
| */ |
| mutex_lock(&wq->mutex); |
| if (!wq->nr_drainers++) |
| wq->flags |= __WQ_DRAINING; |
| mutex_unlock(&wq->mutex); |
| reflush: |
| __flush_workqueue(wq); |
| |
| mutex_lock(&wq->mutex); |
| |
| for_each_pwq(pwq, wq) { |
| bool drained; |
| |
| raw_spin_lock_irq(&pwq->pool->lock); |
| drained = !pwq->nr_active && list_empty(&pwq->inactive_works); |
| raw_spin_unlock_irq(&pwq->pool->lock); |
| |
| if (drained) |
| continue; |
| |
| if (++flush_cnt == 10 || |
| (flush_cnt % 100 == 0 && flush_cnt <= 1000)) |
| pr_warn("workqueue %s: %s() isn't complete after %u tries\n", |
| wq->name, __func__, flush_cnt); |
| |
| mutex_unlock(&wq->mutex); |
| goto reflush; |
| } |
| |
| if (!--wq->nr_drainers) |
| wq->flags &= ~__WQ_DRAINING; |
| mutex_unlock(&wq->mutex); |
| } |
| EXPORT_SYMBOL_GPL(drain_workqueue); |
| |
| static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, |
| bool from_cancel) |
| { |
| struct worker *worker = NULL; |
| struct worker_pool *pool; |
| struct pool_workqueue *pwq; |
| |
| might_sleep(); |
| |
| rcu_read_lock(); |
| pool = get_work_pool(work); |
| if (!pool) { |
| rcu_read_unlock(); |
| return false; |
| } |
| |
| raw_spin_lock_irq(&pool->lock); |
| /* see the comment in try_to_grab_pending() with the same code */ |
| pwq = get_work_pwq(work); |
| if (pwq) { |
| if (unlikely(pwq->pool != pool)) |
| goto already_gone; |
| } else { |
| worker = find_worker_executing_work(pool, work); |
| if (!worker) |
| goto already_gone; |
| pwq = worker->current_pwq; |
| } |
| |
| check_flush_dependency(pwq->wq, work); |
| |
| insert_wq_barrier(pwq, barr, work, worker); |
| raw_spin_unlock_irq(&pool->lock); |
| |
| /* |
| * Force a lock recursion deadlock when using flush_work() inside a |
| * single-threaded or rescuer equipped workqueue. |
| * |
| * For single threaded workqueues the deadlock happens when the work |
| * is after the work issuing the flush_work(). For rescuer equipped |
| * workqueues the deadlock happens when the rescuer stalls, blocking |
| * forward progress. |
| */ |
| if (!from_cancel && |
| (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer)) { |
| lock_map_acquire(&pwq->wq->lockdep_map); |
| lock_map_release(&pwq->wq->lockdep_map); |
| } |
| rcu_read_unlock(); |
| return true; |
| already_gone: |
| raw_spin_unlock_irq(&pool->lock); |
| rcu_read_unlock(); |
| return false; |
| } |
| |
| static bool __flush_work(struct work_struct *work, bool from_cancel) |
| { |
| struct wq_barrier barr; |
| |
| if (WARN_ON(!wq_online)) |
| return false; |
| |
| if (WARN_ON(!work->func)) |
| return false; |
| |
| lock_map_acquire(&work->lockdep_map); |
| lock_map_release(&work->lockdep_map); |
| |
| if (start_flush_work(work, &barr, from_cancel)) { |
| wait_for_completion(&barr.done); |
| destroy_work_on_stack(&barr.work); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| /** |
| * flush_work - wait for a work to finish executing the last queueing instance |
| * @work: the work to flush |
| * |
| * Wait until @work has finished execution. @work is guaranteed to be idle |
| * on return if it hasn't been requeued since flush started. |
| * |
| * Return: |
| * %true if flush_work() waited for the work to finish execution, |
| * %false if it was already idle. |
| */ |
| bool flush_work(struct work_struct *work) |
| { |
| return __flush_work(work, false); |
| } |
| EXPORT_SYMBOL_GPL(flush_work); |
| |
| struct cwt_wait { |
| wait_queue_entry_t wait; |
| struct work_struct *work; |
| }; |
| |
| static int cwt_wakefn(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
| { |
| struct cwt_wait *cwait = container_of(wait, struct cwt_wait, wait); |
| |
| if (cwait->work != key) |
| return 0; |
| return autoremove_wake_function(wait, mode, sync, key); |
| } |
| |
| static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) |
| { |
| static DECLARE_WAIT_QUEUE_HEAD(cancel_waitq); |
| unsigned long flags; |
| int ret; |
| |
| do { |
| ret = try_to_grab_pending(work, is_dwork, &flags); |
| /* |
| * If someone else is already canceling, wait for it to |
| * finish. flush_work() doesn't work for PREEMPT_NONE |
| * because we may get scheduled between @work's completion |
| * and the other canceling task resuming and clearing |
| * CANCELING - flush_work() will return false immediately |
| * as @work is no longer busy, try_to_grab_pending() will |
| * return -ENOENT as @work is still being canceled and the |
| * other canceling task won't be able to clear CANCELING as |
| * we're hogging the CPU. |
| * |
| * Let's wait for completion using a waitqueue. As this |
| * may lead to the thundering herd problem, use a custom |
| * wake function which matches @work along with exclusive |
| * wait and wakeup. |
| */ |
| if (unlikely(ret == -ENOENT)) { |
| struct cwt_wait cwait; |
| |
| init_wait(&cwait.wait); |
| cwait.wait.func = cwt_wakefn; |
| cwait.work = work; |
| |
| prepare_to_wait_exclusive(&cancel_waitq, &cwait.wait, |
| TASK_UNINTERRUPTIBLE); |
| if (work_is_canceling(work)) |
| schedule(); |
| finish_wait(&cancel_waitq, &cwait.wait); |
| } |
| } while (unlikely(ret < 0)); |
| |
| /* tell other tasks trying to grab @work to back off */ |
| mark_work_canceling(work); |
| local_irq_restore(flags); |
| |
| /* |
| * This allows canceling during early boot. We know that @work |
| * isn't executing. |
| */ |
| if (wq_online) |
| __flush_work(work, true); |
| |
| clear_work_data(work); |
| |
| /* |
| * Paired with prepare_to_wait() above so that either |
| * waitqueue_active() is visible here or !work_is_canceling() is |
| * visible there. |
| */ |
| smp_mb(); |
| if (waitqueue_active(&cancel_waitq)) |
| __wake_up(&cancel_waitq, TASK_NORMAL, 1, work); |
| |
| return ret; |
| } |
| |
| /** |
| * cancel_work_sync - cancel a work and wait for it to finish |
| * @work: the work to cancel |
| * |
| * Cancel @work and wait for its execution to finish. This function |
| * can be used even if the work re-queues itself or migrates to |
| * another workqueue. On return from this function, @work is |
| * guaranteed to be not pending or executing on any CPU. |
| * |
| * cancel_work_sync(&delayed_work->work) must not be used for |
| * delayed_work's. Use cancel_delayed_work_sync() instead. |
| * |
| * The caller must ensure that the workqueue on which @work was last |
| * queued can't be destroyed before this function returns. |
| * |
| * Return: |
| * %true if @work was pending, %false otherwise. |
| */ |
| bool cancel_work_sync(struct work_struct *work) |
| { |
| return __cancel_work_timer(work, false); |
| } |
| EXPORT_SYMBOL_GPL(cancel_work_sync); |
| |
| /** |
| * flush_delayed_work - wait for a dwork to finish executing the last queueing |
| * @dwork: the delayed work to flush |
| * |
| * Delayed timer is cancelled and the pending work is queued for |
| * immediate execution. Like flush_work(), this function only |
| * considers the last queueing instance of @dwork. |
| * |
| * Return: |
| * %true if flush_work() waited for the work to finish execution, |
| * %false if it was already idle. |
| */ |
| bool flush_delayed_work(struct delayed_work *dwork) |
| { |
| local_irq_disable(); |
| if (del_timer_sync(&dwork->timer)) |
| __queue_work(dwork->cpu, dwork->wq, &dwork->work); |
| local_irq_enable(); |
| return flush_work(&dwork->work); |
| } |
| EXPORT_SYMBOL(flush_delayed_work); |
| |
| /** |
| * flush_rcu_work - wait for a rwork to finish executing the last queueing |
| * @rwork: the rcu work to flush |
| * |
| * Return: |
| * %true if flush_rcu_work() waited for the work to finish execution, |
| * %false if it was already idle. |
| */ |
| bool flush_rcu_work(struct rcu_work *rwork) |
| { |
| if (test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&rwork->work))) { |
| rcu_barrier(); |
| flush_work(&rwork->work); |
| return true; |
| } else { |
| return flush_work(&rwork->work); |
| } |
| } |
| EXPORT_SYMBOL(flush_rcu_work); |
| |
| static bool __cancel_work(struct work_struct *work, bool is_dwork) |
| { |
| unsigned long flags; |
| int ret; |
| |
| do { |
| ret = try_to_grab_pending(work, is_dwork, &flags); |
| } while (unlikely(ret == -EAGAIN)); |
| |
| if (unlikely(ret < 0)) |
| return false; |
| |
| set_work_pool_and_clear_pending(work, get_work_pool_id(work)); |
| local_irq_restore(flags); |
| return ret; |
| } |
| |
| /* |
| * See cancel_delayed_work() |
| */ |
| bool cancel_work(struct work_struct *work) |
| { |
| return __cancel_work(work, false); |
| } |
| EXPORT_SYMBOL(cancel_work); |
| |
| /** |
| * cancel_delayed_work - cancel a delayed work |
| * @dwork: delayed_work to cancel |
| * |
| * Kill off a pending delayed_work. |
| * |
| * Return: %true if @dwork was pending and canceled; %false if it wasn't |
| * pending. |
| * |
| * Note: |
| * The work callback function may still be running on return, unless |
| * it returns %true and the work doesn't re-arm itself. Explicitly flush or |
| * use cancel_delayed_work_sync() to wait on it. |
| * |
| * This function is safe to call from any context including IRQ handler. |
| */ |
| bool cancel_delayed_work(struct delayed_work *dwork) |
| { |
| return __cancel_work(&dwork->work, true); |
| } |
| EXPORT_SYMBOL(cancel_delayed_work); |
| |
| /** |
| * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish |
| * @dwork: the delayed work cancel |
| * |
| * This is cancel_work_sync() for delayed works. |
| * |
| * Return: |
| * %true if @dwork was pending, %false otherwise. |
| */ |
| bool cancel_delayed_work_sync(struct delayed_work *dwork) |
| { |
| return __cancel_work_timer(&dwork->work, true); |
| } |
| EXPORT_SYMBOL(cancel_delayed_work_sync); |
| |
| /** |
| * schedule_on_each_cpu - execute a function synchronously on each online CPU |
| * @func: the function to call |
| * |
| * schedule_on_each_cpu() executes @func on each online CPU using the |
| * system workqueue and blocks until all CPUs have completed. |
| * schedule_on_each_cpu() is very slow. |
| * |
| * Return: |
| * 0 on success, -errno on failure. |
| */ |
| int schedule_on_each_cpu(work_func_t func) |
| { |
| int cpu; |
| struct work_struct __percpu *works; |
| |
| works = alloc_percpu(struct work_struct); |
| if (!works) |
| return -ENOMEM; |
| |
| cpus_read_lock(); |
| |
| for_each_online_cpu(cpu) { |
| struct work_struct *work = per_cpu_ptr(works, cpu); |
| |
| INIT_WORK(work, func); |
| schedule_work_on(cpu, work); |
| } |
| |
| for_each_online_cpu(cpu) |
| flush_work(per_cpu_ptr(works, cpu)); |
| |
| cpus_read_unlock(); |
| free_percpu(works); |
| return 0; |
| } |
| |
| /** |
| * execute_in_process_context - reliably execute the routine with user context |
| * @fn: the function to execute |
| * @ew: guaranteed storage for the execute work structure (must |
| * be available when the work executes) |
| * |
| * Executes the function immediately if process context is available, |
| * otherwise schedules the function for delayed execution. |
| * |
| * Return: 0 - function was executed |
| * 1 - function was scheduled for execution |
| */ |
| int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
| { |
| if (!in_interrupt()) { |
| fn(&ew->work); |
| return 0; |
| } |
| |
| INIT_WORK(&ew->work, fn); |
| schedule_work(&ew->work); |
| |
| return 1; |
| } |
| EXPORT_SYMBOL_GPL(execute_in_process_context); |
| |
| /** |
| * free_workqueue_attrs - free a workqueue_attrs |
| * @attrs: workqueue_attrs to free |
| * |
| * Undo alloc_workqueue_attrs(). |
| */ |
| void free_workqueue_attrs(struct workqueue_attrs *attrs) |
| { |
| if (attrs) { |
| free_cpumask_var(attrs->cpumask); |
| free_cpumask_var(attrs->__pod_cpumask); |
| kfree(attrs); |
| } |
| } |
| |
| /** |
| * alloc_workqueue_attrs - allocate a workqueue_attrs |
| * |
| * Allocate a new workqueue_attrs, initialize with default settings and |
| * return it. |
| * |
| * Return: The allocated new workqueue_attr on success. %NULL on failure. |
| */ |
| struct workqueue_attrs *alloc_workqueue_attrs(void) |
| { |
| struct workqueue_attrs *attrs; |
| |
| attrs = kzalloc(sizeof(*attrs), GFP_KERNEL); |
| if (!attrs) |
| goto fail; |
| if (!alloc_cpumask_var(&attrs->cpumask, GFP_KERNEL)) |
| goto fail; |
| if (!alloc_cpumask_var(&attrs->__pod_cpumask, GFP_KERNEL)) |
| goto fail; |
| |
| cpumask_copy(attrs->cpumask, cpu_possible_mask); |
| attrs->affn_scope = WQ_AFFN_DFL; |
| return attrs; |
| fail: |
| free_workqueue_attrs(attrs); |
| return NULL; |
| } |
| |
| static void copy_workqueue_attrs(struct workqueue_attrs *to, |
| const struct workqueue_attrs *from) |
| { |
| to->nice = from->nice; |
| cpumask_copy(to->cpumask, from->cpumask); |
| cpumask_copy(to->__pod_cpumask, from->__pod_cpumask); |
| to->affn_strict = from->affn_strict; |
| |
| /* |
| * Unlike hash and equality test, copying shouldn't ignore wq-only |
| * fields as copying is used for both pool and wq attrs. Instead, |
| * get_unbound_pool() explicitly clears the fields. |
| */ |
| to->affn_scope = from->affn_scope; |
| to->ordered = from->ordered; |
| } |
| |
| /* |
| * Some attrs fields are workqueue-only. Clear them for worker_pool's. See the |
| * comments in 'struct workqueue_attrs' definition. |
| */ |
| static void wqattrs_clear_for_pool(struct workqueue_attrs *attrs) |
| { |
| attrs->affn_scope = WQ_AFFN_NR_TYPES; |
| attrs->ordered = false; |
| } |
| |
| /* hash value of the content of @attr */ |
| static u32 wqattrs_hash(const struct workqueue_attrs *attrs) |
| { |
| u32 hash = 0; |
| |
| hash = jhash_1word(attrs->nice, hash); |
| hash = jhash(cpumask_bits(attrs->cpumask), |
| BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash); |
| hash = jhash(cpumask_bits(attrs->__pod_cpumask), |
| BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash); |
| hash = jhash_1word(attrs->affn_strict, hash); |
| return hash; |
| } |
| |
| /* content equality test */ |
| static bool wqattrs_equal(const struct workqueue_attrs *a, |
| const struct workqueue_attrs *b) |
| { |
| if (a->nice != b->nice) |
| return false; |
| if (!cpumask_equal(a->cpumask, b->cpumask)) |
| return false; |
| if (!cpumask_equal(a->__pod_cpumask, b->__pod_cpumask)) |
| return false; |
| if (a->affn_strict != b->affn_strict) |
| return false; |
| return true; |
| } |
| |
| /* Update @attrs with actually available CPUs */ |
| static void wqattrs_actualize_cpumask(struct workqueue_attrs *attrs, |
| const cpumask_t *unbound_cpumask) |
| { |
| /* |
| * Calculate the effective CPU mask of @attrs given @unbound_cpumask. If |
| * @attrs->cpumask doesn't overlap with @unbound_cpumask, we fallback to |
| * @unbound_cpumask. |
| */ |
| cpumask_and(attrs->cpumask, attrs->cpumask, unbound_cpumask); |
| if (unlikely(cpumask_empty(attrs->cpumask))) |
| cpumask_copy(attrs->cpumask, unbound_cpumask); |
| } |
| |
| /* find wq_pod_type to use for @attrs */ |
| static const struct wq_pod_type * |
| wqattrs_pod_type(const struct workqueue_attrs *attrs) |
| { |
| enum wq_affn_scope scope; |
| struct wq_pod_type *pt; |
| |
| /* to synchronize access to wq_affn_dfl */ |
| lockdep_assert_held(&wq_pool_mutex); |
| |
| if (attrs->affn_scope == WQ_AFFN_DFL) |
| scope = wq_affn_dfl; |
| else |
| scope = attrs->affn_scope; |
| |
| pt = &wq_pod_types[scope]; |
| |
| if (!WARN_ON_ONCE(attrs->affn_scope == WQ_AFFN_NR_TYPES) && |
| likely(pt->nr_pods)) |
| return pt; |
| |
| /* |
| * Before workqueue_init_topology(), only SYSTEM is available which is |
| * initialized in workqueue_init_early(). |
| */ |
| pt = &wq_pod_types[WQ_AFFN_SYSTEM]; |
| BUG_ON(!pt->nr_pods); |
| return pt; |
| } |
| |
| /** |
| * init_worker_pool - initialize a newly zalloc'd worker_pool |
| * @pool: worker_pool to initialize |
| * |
| * Initialize a newly zalloc'd @pool. It also allocates @pool->attrs. |
| * |
| * Return: 0 on success, -errno on failure. Even on failure, all fields |
| * inside @pool proper are initialized and put_unbound_pool() can be called |
| * on @pool safely to release it. |
| */ |
| static int init_worker_pool(struct worker_pool *pool) |
| { |
| raw_spin_lock_init(&pool->lock); |
| pool->id = -1; |
| pool->cpu = -1; |
| pool->node = NUMA_NO_NODE; |
| pool->flags |= POOL_DISASSOCIATED; |
| pool->watchdog_ts = jiffies; |
| INIT_LIST_HEAD(&pool->worklist); |
| INIT_LIST_HEAD(&pool->idle_list); |
| hash_init(pool->busy_hash); |
| |
| timer_setup(&pool->idle_timer, idle_worker_timeout, TIMER_DEFERRABLE); |
| INIT_WORK(&pool->idle_cull_work, idle_cull_fn); |
| |
| timer_setup(&pool->mayday_timer, pool_mayday_timeout, 0); |
| |
| INIT_LIST_HEAD(&pool->workers); |
| INIT_LIST_HEAD(&pool->dying_workers); |
| |
| ida_init(&pool->worker_ida); |
| INIT_HLIST_NODE(&pool->hash_node); |
| pool->refcnt = 1; |
| |
| /* shouldn't fail above this point */ |
| pool->attrs = alloc_workqueue_attrs(); |
| if (!pool->attrs) |
| return -ENOMEM; |
| |
| wqattrs_clear_for_pool(pool->attrs); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_LOCKDEP |
| static void wq_init_lockdep(struct workqueue_struct *wq) |
| { |
| char *lock_name; |
| |
| lockdep_register_key(&wq->key); |
| lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name); |
| if (!lock_name) |
| lock_name = wq->name; |
| |
| wq->lock_name = lock_name; |
| lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0); |
| } |
| |
| static void wq_unregister_lockdep(struct workqueue_struct *wq) |
| { |
| lockdep_unregister_key(&wq->key); |
| } |
| |
| static void wq_free_lockdep(struct workqueue_struct *wq) |
| { |
| if (wq->lock_name != wq->name) |
| kfree(wq->lock_name); |
| } |
| #else |
| static void wq_init_lockdep(struct workqueue_struct *wq) |
| { |
| } |
| |
| static void wq_unregister_lockdep(struct workqueue_struct *wq) |
| { |
| } |
| |
| static void wq_free_lockdep(struct workqueue_struct *wq) |
| { |
| } |
| #endif |
| |
| static void rcu_free_wq(struct rcu_head *rcu) |
| { |
| struct workqueue_struct *wq = |
| container_of(rcu, struct workqueue_struct, rcu); |
| |
| wq_free_lockdep(wq); |
| free_percpu(wq->cpu_pwq); |
| free_workqueue_attrs(wq->unbound_attrs); |
| kfree(wq); |
| } |
| |
| static void rcu_free_pool(struct rcu_head *rcu) |
| { |
| struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu); |
| |
| ida_destroy(&pool->worker_ida); |
| free_workqueue_attrs(pool->attrs); |
| kfree(pool); |
| } |
| |
| /** |
| * put_unbound_pool - put a worker_pool |
| * @pool: worker_pool to put |
| * |
| * Put @pool. If its refcnt reaches zero, it gets destroyed in RCU |
| * safe manner. get_unbound_pool() calls this function on its failure path |
| * and this function should be able to release pools which went through, |
| * successfully or not, init_worker_pool(). |
| * |
| * Should be called with wq_pool_mutex held. |
| */ |
| static void put_unbound_pool(struct worker_pool *pool) |
| { |
| DECLARE_COMPLETION_ONSTACK(detach_completion); |
| struct worker *worker; |
| LIST_HEAD(cull_list); |
| |
| lockdep_assert_held(&wq_pool_mutex); |
| |
| if (--pool->refcnt) |
| return; |
| |
| /* sanity checks */ |
| if (WARN_ON(!(pool->cpu < 0)) || |
| WARN_ON(!list_empty(&pool->worklist))) |
| return; |
| |
| /* release id and unhash */ |
| if (pool->id >= 0) |
| idr_remove(&worker_pool_idr, pool->id); |
| hash_del(&pool->hash_node); |
| |
| /* |
| * Become the manager and destroy all workers. This prevents |
| * @pool's workers from blocking on attach_mutex. We're the last |
| * manager and @pool gets freed with the flag set. |
| * |
| * Having a concurrent manager is quite unlikely to happen as we can |
| * only get here with |
| * pwq->refcnt == pool->refcnt == 0 |
| * which implies no work queued to the pool, which implies no worker can |
| * become the manager. However a worker could have taken the role of |
| * manager before the refcnts dropped to 0, since maybe_create_worker() |
| * drops pool->lock |
| */ |
| while (true) { |
| rcuwait_wait_event(&manager_wait, |
| !(pool->flags & POOL_MANAGER_ACTIVE), |
| TASK_UNINTERRUPTIBLE); |
| |
| mutex_lock(&wq_pool_attach_mutex); |
| raw_spin_lock_irq(&pool->lock); |
| if (!(pool->flags & POOL_MANAGER_ACTIVE)) { |
| pool->flags |= POOL_MANAGER_ACTIVE; |
| break; |
| } |
| raw_spin_unlock_irq(&pool->lock); |
| mutex_unlock(&wq_pool_attach_mutex); |
| } |
| |
| while ((worker = first_idle_worker(pool))) |
| set_worker_dying(worker, &cull_list); |
| WARN_ON(pool->nr_workers || pool->nr_idle); |
| raw_spin_unlock_irq(&pool->lock); |
| |
| wake_dying_workers(&cull_list); |
| |
| if (!list_empty(&pool->workers) || !list_empty(&pool->dying_workers)) |
| pool->detach_completion = &detach_completion; |
| mutex_unlock(&wq_pool_attach_mutex); |
| |
| if (pool->detach_completion) |
| wait_for_completion(pool->detach_completion); |
| |
| /* shut down the timers */ |
| del_timer_sync(&pool->idle_timer); |
| cancel_work_sync(&pool->idle_cull_work); |
| del_timer_sync(&pool->mayday_timer); |
| |
| /* RCU protected to allow dereferences from get_work_pool() */ |
| call_rcu(&pool->rcu, rcu_free_pool); |
| } |
| |
| /** |
| * get_unbound_pool - get a worker_pool with the specified attributes |
| * @attrs: the attributes of the worker_pool to get |
| * |
| * Obtain a worker_pool which has the same attributes as @attrs, bump the |
| * reference count and return it. If there already is a matching |
| * worker_pool, it will be used; otherwise, this function attempts to |
| * create a new one. |
| * |
| * Should be called with wq_pool_mutex held. |
| * |
| * Return: On success, a worker_pool with the same attributes as @attrs. |
| * On failure, %NULL. |
| */ |
| static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) |
| { |
| struct wq_pod_type *pt = &wq_pod_types[WQ_AFFN_NUMA]; |
| u32 hash = wqattrs_hash(attrs); |
| struct worker_pool *pool; |
| int pod, node = NUMA_NO_NODE; |
| |
| lockdep_assert_held(&wq_pool_mutex); |
| |
| /* do we already have a matching pool? */ |
| hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) { |
| if (wqattrs_equal(pool->attrs, attrs)) { |
| pool->refcnt++; |
| return pool; |
| } |
| } |
| |
| /* If __pod_cpumask is contained inside a NUMA pod, that's our node */ |
| for (pod = 0; pod < pt->nr_pods; pod++) { |
| if (cpumask_subset(attrs->__pod_cpumask, pt->pod_cpus[pod])) { |
| node = pt->pod_node[pod]; |
| break; |
| } |
| } |
| |
| /* nope, create a new one */ |
| pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, node); |
| if (!pool || init_worker_pool(pool) < 0) |
| goto fail; |
| |
| pool->node = node; |
| copy_workqueue_attrs(pool->attrs, attrs); |
| wqattrs_clear_for_pool(pool->attrs); |
| |
| if (worker_pool_assign_id(pool) < 0) |
| goto fail; |
| |
| /* create and start the initial worker */ |
| if (wq_online && !create_worker(pool)) |
| goto fail; |
| |
| /* install */ |
| hash_add(unbound_pool_hash, &pool->hash_node, hash); |
| |
| return pool; |
| fail: |
| if (pool) |
| put_unbound_pool(pool); |
| return NULL; |
| } |
| |
| static void rcu_free_pwq(struct rcu_head *rcu) |
| { |
| kmem_cache_free(pwq_cache, |
| container_of(rcu, struct pool_workqueue, rcu)); |
| } |
| |
| /* |
| * Scheduled on pwq_release_worker by put_pwq() when an unbound pwq hits zero |
| * refcnt and needs to be destroyed. |
| */ |
| static void pwq_release_workfn(struct kthread_work *work) |
| { |
| struct pool_workqueue *pwq = container_of(work, struct pool_workqueue, |
| release_work); |
| struct workqueue_struct *wq = pwq->wq; |
| struct worker_pool *pool = pwq->pool; |
| bool is_last = false; |
| |
| /* |
| * When @pwq is not linked, it doesn't hold any reference to the |
| * @wq, and @wq is invalid to access. |
| */ |
| if (!list_empty(&pwq->pwqs_node)) { |
| mutex_lock(&wq->mutex); |
| list_del_rcu(&pwq->pwqs_node); |
| is_last = list_empty(&wq->pwqs); |
| mutex_unlock(&wq->mutex); |
| } |
| |
| if (wq->flags & WQ_UNBOUND) { |
| mutex_lock(&wq_pool_mutex); |
| put_unbound_pool(pool); |
| mutex_unlock(&wq_pool_mutex); |
| } |
| |
| call_rcu(&pwq->rcu, rcu_free_pwq); |
| |
| /* |
| * If we're the last pwq going away, @wq is already dead and no one |
| * is gonna access it anymore. Schedule RCU free. |
| */ |
| if (is_last) { |
| wq_unregister_lockdep(wq); |
| call_rcu(&wq->rcu, rcu_free_wq); |
| } |
| } |
| |
| /** |
| * pwq_adjust_max_active - update a pwq's max_active to the current setting |
| * @pwq: target pool_workqueue |
| * |
| * If @pwq isn't freezing, set @pwq->max_active to the associated |
| * workqueue's saved_max_active and activate inactive work items |
| * accordingly. If @pwq is freezing, clear @pwq->max_active to zero. |
| */ |
| static void pwq_adjust_max_active(struct pool_workqueue *pwq) |
| { |
| struct workqueue_struct *wq = pwq->wq; |
| bool freezable = wq->flags & WQ_FREEZABLE; |
| unsigned long flags; |
| |
| /* for @wq->saved_max_active */ |
| lockdep_assert_held(&wq->mutex); |
| |
| /* fast exit for non-freezable wqs */ |
| if (!freezable && pwq->max_active == wq->saved_max_active) |
| return; |
| |
| /* this function can be called during early boot w/ irq disabled */ |
| raw_spin_lock_irqsave(&pwq->pool->lock, flags); |
| |
| /* |
| * During [un]freezing, the caller is responsible for ensuring that |
| * this function is called at least once after @workqueue_freezing |
| * is updated and visible. |
| */ |
| if (!freezable || !workqueue_freezing) { |
| pwq->max_active = wq->saved_max_active; |
| |
| while (!list_empty(&pwq->inactive_works) && |
| pwq->nr_active < pwq->max_active) |
| pwq_activate_first_inactive(pwq); |
| |
| kick_pool(pwq->pool); |
| } else { |
| pwq->max_active = 0; |
| } |
| |
| raw_spin_unlock_irqrestore(&pwq->pool->lock, flags); |
| } |
| |
| /* initialize newly allocated @pwq which is associated with @wq and @pool */ |
| static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq, |
| struct worker_pool *pool) |
| { |
| BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK); |
| |
| memset(pwq, 0, sizeof(*pwq)); |
| |
| pwq->pool = pool; |
| pwq->wq = wq; |
| pwq->flush_color = -1; |
| pwq->refcnt = 1; |
| INIT_LIST_HEAD(&pwq->inactive_works); |
| INIT_LIST_HEAD(&pwq->pwqs_node); |
| INIT_LIST_HEAD(&pwq->mayday_node); |
| kthread_init_work(&pwq->release_work, pwq_release_workfn); |
| } |
| |
| /* sync @pwq with the current state of its associated wq and link it */ |
| static void link_pwq(struct pool_workqueue *pwq) |
| { |
| struct workqueue_struct *wq = pwq->wq; |
| |
| lockdep_assert_held(&wq->mutex); |
| |
| /* may be called multiple times, ignore if already linked */ |
| if (!list_empty(&pwq->pwqs_node)) |
| return; |
| |
| /* set the matching work_color */ |
| pwq->work_color = wq->work_color; |
| |
| /* sync max_active to the current setting */ |
| pwq_adjust_max_active(pwq); |
| |
| /* link in @pwq */ |
| list_add_rcu(&pwq->pwqs_node, &wq->pwqs); |
| } |
| |
| /* obtain a pool matching @attr and create a pwq associating the pool and @wq */ |
| static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq, |
| const struct workqueue_attrs *attrs) |
| { |
| struct worker_pool *pool; |
| struct pool_workqueue *pwq; |
| |
| lockdep_assert_held(&wq_pool_mutex); |
| |
| pool = get_unbound_pool(attrs); |
| if (!pool) |
| return NULL; |
| |
| pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node); |
| if (!pwq) { |
| put_unbound_pool(pool); |
| return NULL; |
| } |
| |
| init_pwq(pwq, wq, pool); |
| return pwq; |
| } |
| |
| /** |
| * wq_calc_pod_cpumask - calculate a wq_attrs' cpumask for a pod |
| * @attrs: the wq_attrs of the default pwq of the target workqueue |
| * @cpu: the target CPU |
| * @cpu_going_down: if >= 0, the CPU to consider as offline |
| * |
| * Calculate the cpumask a workqueue with @attrs should use on @pod. If |
| * @cpu_going_down is >= 0, that cpu is considered offline during calculation. |
| * The result is stored in @attrs->__pod_cpumask. |
| * |
| * If pod affinity is not enabled, @attrs->cpumask is always used. If enabled |
| * and @pod has online CPUs requested by @attrs, the returned cpumask is the |
| * intersection of the possible CPUs of @pod and @attrs->cpumask. |
| * |
| * The caller is responsible for ensuring that the cpumask of @pod stays stable. |
| */ |
| static void wq_calc_pod_cpumask(struct workqueue_attrs *attrs, int cpu, |
| int cpu_going_down) |
| { |
| const struct wq_pod_type *pt = wqattrs_pod_type(attrs); |
| int pod = pt->cpu_pod[cpu]; |
| |
| /* does @pod have any online CPUs @attrs wants? */ |
| cpumask_and(attrs->__pod_cpumask, pt->pod_cpus[pod], attrs->cpumask); |
| cpumask_and(attrs->__pod_cpumask, attrs->__pod_cpumask, cpu_online_mask); |
| if (cpu_going_down >= 0) |
| cpumask_clear_cpu(cpu_going_down, attrs->__pod_cpumask); |
| |
| if (cpumask_empty(attrs->__pod_cpumask)) { |
| cpumask_copy(attrs->__pod_cpumask, attrs->cpumask); |
| return; |
| } |
| |
| /* yeap, return possible CPUs in @pod that @attrs wants */ |
| cpumask_and(attrs->__pod_cpumask, attrs->cpumask, pt->pod_cpus[pod]); |
| |
| if (cpumask_empty(attrs->__pod_cpumask)) |
| pr_warn_once("WARNING: workqueue cpumask: online intersect > " |
| "possible intersect\n"); |
| } |
| |
| /* install @pwq into @wq's cpu_pwq and return the old pwq */ |
| static struct pool_workqueue *install_unbound_pwq(struct workqueue_struct *wq, |
| int cpu, struct pool_workqueue *pwq) |
| { |
| struct pool_workqueue *old_pwq; |
| |
| lockdep_assert_held(&wq_pool_mutex); |
| lockdep_assert_held(&wq->mutex); |
| |
| /* link_pwq() can handle duplicate calls */ |
| link_pwq(pwq); |
| |
| old_pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu)); |
| rcu_assign_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu), pwq); |
| return old_pwq; |
| } |
| |
| /* context to store the prepared attrs & pwqs before applying */ |
| struct apply_wqattrs_ctx { |
| struct workqueue_struct *wq; /* target workqueue */ |
| struct workqueue_attrs *attrs; /* attrs to apply */ |
| struct list_head list; /* queued for batching commit */ |
| struct pool_workqueue *dfl_pwq; |
| struct pool_workqueue *pwq_tbl[]; |
| }; |
| |
| /* free the resources after success or abort */ |
| static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx) |
| { |
| if (ctx) { |
| int cpu; |
| |
| for_each_possible_cpu(cpu) |
| put_pwq_unlocked(ctx->pwq_tbl[cpu]); |
| put_pwq_unlocked(ctx->dfl_pwq); |
| |
| free_workqueue_attrs(ctx->attrs); |
| |
| kfree(ctx); |
| } |
| } |
| |
| /* allocate the attrs and pwqs for later installation */ |
| static struct apply_wqattrs_ctx * |
| apply_wqattrs_prepare(struct workqueue_struct *wq, |
| const struct workqueue_attrs *attrs, |
| const cpumask_var_t unbound_cpumask) |
| { |
| struct apply_wqattrs_ctx *ctx; |
| struct workqueue_attrs *new_attrs; |
| int cpu; |
| |
| lockdep_assert_held(&wq_pool_mutex); |
| |
| if (WARN_ON(attrs->affn_scope < 0 || |
| attrs->affn_scope >= WQ_AFFN_NR_TYPES)) |
| return ERR_PTR(-EINVAL); |
| |
| ctx = kzalloc(struct_size(ctx, pwq_tbl, nr_cpu_ids), GFP_KERNEL); |
| |
| new_attrs = alloc_workqueue_attrs(); |
| if (!ctx || !new_attrs) |
| goto out_free; |
| |
| /* |
| * If something goes wrong during CPU up/down, we'll fall back to |
| * the default pwq covering whole @attrs->cpumask. Always create |
| * it even if we don't use it immediately. |
| */ |
| copy_workqueue_attrs(new_attrs, attrs); |
| wqattrs_actualize_cpumask(new_attrs, unbound_cpumask); |
| cpumask_copy(new_attrs->__pod_cpumask, new_attrs->cpumask); |
| ctx->dfl_pwq = alloc_unbound_pwq(wq, new_attrs); |
| if (!ctx->dfl_pwq) |
| goto out_free; |
| |
| for_each_possible_cpu(cpu) { |
| if (new_attrs->ordered) { |
| ctx->dfl_pwq->refcnt++; |
| ctx->pwq_tbl[cpu] = ctx->dfl_pwq; |
| } else { |
| wq_calc_pod_cpumask(new_attrs, cpu, -1); |
| ctx->pwq_tbl[cpu] = alloc_unbound_pwq(wq, new_attrs); |
| if (!ctx->pwq_tbl[cpu]) |
| goto out_free; |
| } |
| } |
| |
| /* save the user configured attrs and sanitize it. */ |
| copy_workqueue_attrs(new_attrs, attrs); |
| cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask); |
| cpumask_copy(new_attrs->__pod_cpumask, new_attrs->cpumask); |
| ctx->attrs = new_attrs; |
| |
| ctx->wq = wq; |
| return ctx; |
| |
| out_free: |
| free_workqueue_attrs(new_attrs); |
| apply_wqattrs_cleanup(ctx); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| /* set attrs and install prepared pwqs, @ctx points to old pwqs on return */ |
| static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx) |
| { |
| int cpu; |
| |
| /* all pwqs have been created successfully, let's install'em */ |
| mutex_lock(&ctx->wq->mutex); |
| |
| copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs); |
| |
| /* save the previous pwq and install the new one */ |
| for_each_possible_cpu(cpu) |
| ctx->pwq_tbl[cpu] = install_unbound_pwq(ctx->wq, cpu, |
| ctx->pwq_tbl[cpu]); |
| |
| /* @dfl_pwq might not have been used, ensure it's linked */ |
| link_pwq(ctx->dfl_pwq); |
| swap(ctx->wq->dfl_pwq, ctx->dfl_pwq); |
| |
| mutex_unlock(&ctx->wq->mutex); |
| } |
| |
| static void apply_wqattrs_lock(void) |
| { |
| /* CPUs should stay stable across pwq creations and installations */ |
| cpus_read_lock(); |
| mutex_lock(&wq_pool_mutex); |
| } |
| |
| static void apply_wqattrs_unlock(void) |
| { |
| mutex_unlock(&wq_pool_mutex); |
| cpus_read_unlock(); |
| } |
| |
| static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, |
| const struct workqueue_attrs *attrs) |
| { |
| struct apply_wqattrs_ctx *ctx; |
| |
| /* only unbound workqueues can change attributes */ |
| if (WARN_ON(!(wq->flags & WQ_UNBOUND))) |
| return -EINVAL; |
| |
| /* creating multiple pwqs breaks ordering guarantee */ |
| if (!list_empty(&wq->pwqs)) { |
| if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) |
| return -EINVAL; |
| |
| wq->flags &= ~__WQ_ORDERED; |
| } |
| |
| ctx = apply_wqattrs_prepare(wq, attrs, wq_unbound_cpumask); |
| if (IS_ERR(ctx)) |
| return PTR_ERR(ctx); |
| |
| /* the ctx has been prepared successfully, let's commit it */ |
| apply_wqattrs_commit(ctx); |
| apply_wqattrs_cleanup(ctx); |
| |
| return 0; |
| } |
| |
| /** |
| * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue |
| * @wq: the target workqueue |
| * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs() |
| * |
| * Apply @attrs to an unbound workqueue @wq. Unless disabled, this function maps |
| * a separate pwq to each CPU pod with possibles CPUs in @attrs->cpumask so that |
| * work items are affine to the pod it was issued on. Older pwqs are released as |
| * in-flight work items finish. Note that a work item which repeatedly requeues |
| * itself back-to-back will stay on its current pwq. |
| * |
| * Performs GFP_KERNEL allocations. |
| * |
| * Assumes caller has CPU hotplug read exclusion, i.e. cpus_read_lock(). |
| * |
| * Return: 0 on success and -errno on failure. |
| */ |
| int apply_workqueue_attrs(struct workqueue_struct *wq, |
| const struct workqueue_attrs *attrs) |
| { |
| int ret; |
| |
| lockdep_assert_cpus_held(); |
| |
| mutex_lock(&wq_pool_mutex); |
| ret = apply_workqueue_attrs_locked(wq, attrs); |
| mutex_unlock(&wq_pool_mutex); |
| |
| return ret; |
| } |
| |
| /** |
| * wq_update_pod - update pod affinity of a wq for CPU hot[un]plug |
| * @wq: the target workqueue |
| * @cpu: the CPU to update pool association for |
| * @hotplug_cpu: the CPU coming up or going down |
| * @online: whether @cpu is coming up or going down |
| * |
| * This function is to be called from %CPU_DOWN_PREPARE, %CPU_ONLINE and |
| * %CPU_DOWN_FAILED. @cpu is being hot[un]plugged, update pod affinity of |
| * @wq accordingly. |
| * |
| * |
| * If pod affinity can't be adjusted due to memory allocation failure, it falls |
| * back to @wq->dfl_pwq which may not be optimal but is always correct. |
| * |
| * Note that when the last allowed CPU of a pod goes offline for a workqueue |
| * with a cpumask spanning multiple pods, the workers which were already |
| * executing the work items for the workqueue will lose their CPU affinity and |
| * may execute on any CPU. This is similar to how per-cpu workqueues behave on |
| * CPU_DOWN. If a workqueue user wants strict affinity, it's the user's |
| * responsibility to flush the work item from CPU_DOWN_PREPARE. |
| */ |
| static void wq_update_pod(struct workqueue_struct *wq, int cpu, |
| int hotplug_cpu, bool online) |
| { |
| int off_cpu = online ? -1 : hotplug_cpu; |
| struct pool_workqueue *old_pwq = NULL, *pwq; |
| struct workqueue_attrs *target_attrs; |
| |
| lockdep_assert_held(&wq_pool_mutex); |
| |
| if (!(wq->flags & WQ_UNBOUND) || wq->unbound_attrs->ordered) |
| return; |
| |
| /* |
| * We don't wanna alloc/free wq_attrs for each wq for each CPU. |
| * Let's use a preallocated one. The following buf is protected by |
| * CPU hotplug exclusion. |
| */ |
| target_attrs = wq_update_pod_attrs_buf; |
| |
| copy_workqueue_attrs(target_attrs, wq->unbound_attrs); |
| wqattrs_actualize_cpumask(target_attrs, wq_unbound_cpumask); |
| |
| /* nothing to do if the target cpumask matches the current pwq */ |
| wq_calc_pod_cpumask(target_attrs, cpu, off_cpu); |
| pwq = rcu_dereference_protected(*per_cpu_ptr(wq->cpu_pwq, cpu), |
| lockdep_is_held(&wq_pool_mutex)); |
| if (wqattrs_equal(target_attrs, pwq->pool->attrs)) |
| return; |
| |
| /* create a new pwq */ |
| pwq = alloc_unbound_pwq(wq, target_attrs); |
| if (!pwq) { |
| pr_warn("workqueue: allocation failed while updating CPU pod affinity of \"%s\"\n", |
| wq->name); |
| goto use_dfl_pwq; |
| } |
| |
| /* Install the new pwq. */ |
| mutex_lock(&wq->mutex); |
| old_pwq = install_unbound_pwq(wq, cpu, pwq); |
| goto out_unlock; |
| |
| use_dfl_pwq: |
| mutex_lock(&wq->mutex); |
| raw_spin_lock_irq(&wq->dfl_pwq->pool->lock); |
| get_pwq(wq->dfl_pwq); |
| raw_spin_unlock_irq(&wq->dfl_pwq->pool->lock); |
| old_pwq = install_unbound_pwq(wq, cpu, wq->dfl_pwq); |
| out_unlock: |
| mutex_unlock(&wq->mutex); |
| put_pwq_unlocked(old_pwq); |
| } |
| |
| static int alloc_and_link_pwqs(struct workqueue_struct *wq) |
| { |
| bool highpri = wq->flags & WQ_HIGHPRI; |
| int cpu, ret; |
| |
| wq->cpu_pwq = alloc_percpu(struct pool_workqueue *); |
| if (!wq->cpu_pwq) |
| goto enomem; |
| |
| if (!(wq->flags & WQ_UNBOUND)) { |
| for_each_possible_cpu(cpu) { |
| struct pool_workqueue **pwq_p = |
| per_cpu_ptr(wq->cpu_pwq, cpu); |
| struct worker_pool *pool = |
| &(per_cpu_ptr(cpu_worker_pools, cpu)[highpri]); |
| |
| *pwq_p = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, |
| pool->node); |
| if (!*pwq_p) |
| goto enomem; |
| |
| init_pwq(*pwq_p, wq, pool); |
| |
| mutex_lock(&wq->mutex); |
| link_pwq(*pwq_p); |
| mutex_unlock(&wq->mutex); |
| } |
| return 0; |
| } |
| |
| cpus_read_lock(); |
| if (wq->flags & __WQ_ORDERED) { |
| ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]); |
| /* there should only be single pwq for ordering guarantee */ |
| WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node || |
| wq->pwqs.prev != &wq->dfl_pwq->pwqs_node), |
| "ordering guarantee broken for workqueue %s\n", wq->name); |
| } else { |
| ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]); |
| } |
| cpus_read_unlock(); |
| |
| /* for unbound pwq, flush the pwq_release_worker ensures that the |
| * pwq_release_workfn() completes before calling kfree(wq). |
| */ |
| if (ret) |
| kthread_flush_worker(pwq_release_worker); |
| |
| return ret; |
| |
| enomem: |
| if (wq->cpu_pwq) { |
| for_each_possible_cpu(cpu) { |
| struct pool_workqueue *pwq = *per_cpu_ptr(wq->cpu_pwq, cpu); |
| |
| if (pwq) |
| kmem_cache_free(pwq_cache, pwq); |
| } |
| free_percpu(wq->cpu_pwq); |
| wq->cpu_pwq = NULL; |
| } |
| return -ENOMEM; |
| } |
| |
| static int wq_clamp_max_active(int max_active, unsigned int flags, |
| const char *name) |
| { |
| if (max_active < 1 || max_active > WQ_MAX_ACTIVE) |
| pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n", |
| max_active, name, 1, WQ_MAX_ACTIVE); |
| |
| return clamp_val(max_active, 1, WQ_MAX_ACTIVE); |
| } |
| |
| /* |
| * Workqueues which may be used during memory reclaim should have a rescuer |
| * to guarantee forward progress. |
| */ |
| static int init_rescuer(struct workqueue_struct *wq) |
| { |
| struct worker *rescuer; |
| int ret; |
| |
| if (!(wq->flags & WQ_MEM_RECLAIM)) |
| return 0; |
| |
| rescuer = alloc_worker(NUMA_NO_NODE); |
| if (!rescuer) { |
| pr_err("workqueue: Failed to allocate a rescuer for wq \"%s\"\n", |
| wq->name); |
| return -ENOMEM; |
| } |
| |
| rescuer->rescue_wq = wq; |
| rescuer->task = kthread_create(rescuer_thread, rescuer, "kworker/R-%s", wq->name); |
| if (IS_ERR(rescuer->task)) { |
| ret = PTR_ERR(rescuer->task); |
| pr_err("workqueue: Failed to create a rescuer kthread for wq \"%s\": %pe", |
| wq->name, ERR_PTR(ret)); |
| kfree(rescuer); |
| return ret; |
| } |
| |
| wq->rescuer = rescuer; |
| kthread_bind_mask(rescuer->task, cpu_possible_mask); |
| wake_up_process(rescuer->task); |
| |
| return 0; |
| } |
| |
| __printf(1, 4) |
| struct workqueue_struct *alloc_workqueue(const char *fmt, |
| unsigned int flags, |
| int max_active, ...) |
| { |
| va_list args; |
| struct workqueue_struct *wq; |
| struct pool_workqueue *pwq; |
| |
| /* |
| * Unbound && max_active == 1 used to imply ordered, which is no longer |
| * the case on many machines due to per-pod pools. While |
| * alloc_ordered_workqueue() is the right way to create an ordered |
| * workqueue, keep the previous behavior to avoid subtle breakages. |
| */ |
| if ((flags & WQ_UNBOUND) && max_active == 1) |
| flags |= __WQ_ORDERED; |
| |
| /* see the comment above the definition of WQ_POWER_EFFICIENT */ |
| if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient) |
| flags |= WQ_UNBOUND; |
| |
| /* allocate wq and format name */ |
| wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
| if (!wq) |
| return NULL; |
| |
| if (flags & WQ_UNBOUND) { |
| wq->unbound_attrs = alloc_workqueue_attrs(); |
| if (!wq->unbound_attrs) |
| goto err_free_wq; |
| } |
| |
| va_start(args, max_active); |
| vsnprintf(wq->name, sizeof(wq->name), fmt, args); |
| va_end(args); |
| |
| max_active = max_active ?: WQ_DFL_ACTIVE; |
| max_active = wq_clamp_max_active(max_active, flags, wq->name); |
| |
| /* init wq */ |
| wq->flags = flags; |
| wq->saved_max_active = max_active; |
| mutex_init(&wq->mutex); |
| atomic_set(&wq->nr_pwqs_to_flush, 0); |
| INIT_LIST_HEAD(&wq->pwqs); |
| INIT_LIST_HEAD(&wq->flusher_queue); |
| INIT_LIST_HEAD(&wq->flusher_overflow); |
| INIT_LIST_HEAD(&wq->maydays); |
| |
| wq_init_lockdep(wq); |
| INIT_LIST_HEAD(&wq->list); |
| |
| if (alloc_and_link_pwqs(wq) < 0) |
| goto err_unreg_lockdep; |
| |
| if (wq_online && init_rescuer(wq) < 0) |
| goto err_destroy; |
| |
| if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq)) |
| goto err_destroy; |
| |
| /* |
| * wq_pool_mutex protects global freeze state and workqueues list. |
| * Grab it, adjust max_active and add the new @wq to workqueues |
| * list. |
| */ |
| mutex_lock(&wq_pool_mutex); |
| |
| mutex_lock(&wq->mutex); |
| for_each_pwq(pwq, wq) |
| pwq_adjust_max_active(pwq); |
| mutex_unlock(&wq->mutex); |
| |
| list_add_tail_rcu(&wq->list, &workqueues); |
| |
| mutex_unlock(&wq_pool_mutex); |
| |
| return wq; |
| |
| err_unreg_lockdep: |
| wq_unregister_lockdep(wq); |
| wq_free_lockdep(wq); |
| err_free_wq: |
| free_workqueue_attrs(wq->unbound_attrs); |
| kfree(wq); |
| return NULL; |
| err_destroy: |
| destroy_workqueue(wq); |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(alloc_workqueue); |
| |
| static bool pwq_busy(struct pool_workqueue *pwq) |
| { |
| int i; |
| |
| for (i = 0; i < WORK_NR_COLORS; i++) |
| if (pwq->nr_in_flight[i]) |
| return true; |
| |
| if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1)) |
| return true; |
| if (pwq->nr_active || !list_empty(&pwq->inactive_works)) |
| return true; |
| |
| return false; |
| } |
| |
| /** |
| * destroy_workqueue - safely terminate a workqueue |
| * @wq: target workqueue |
| * |
| * Safely destroy a workqueue. All work currently pending will be done first. |
| */ |
| void destroy_workqueue(struct workqueue_struct *wq) |
| { |
| struct pool_workqueue *pwq; |
| int cpu; |
| |
| /* |
| * Remove it from sysfs first so that sanity check failure doesn't |
| * lead to sysfs name conflicts. |
| */ |
| workqueue_sysfs_unregister(wq); |
| |
| /* mark the workqueue destruction is in progress */ |
| mutex_lock(&wq->mutex); |
| wq->flags |= __WQ_DESTROYING; |
| mutex_unlock(&wq->mutex); |
| |
| /* drain it before proceeding with destruction */ |
| drain_workqueue(wq); |
| |
| /* kill rescuer, if sanity checks fail, leave it w/o rescuer */ |
| if (wq->rescuer) { |
| struct worker *rescuer = wq->rescuer; |
| |
| /* this prevents new queueing */ |
| raw_spin_lock_irq(&wq_mayday_lock); |
| wq->rescuer = NULL; |
| raw_spin_unlock_irq(&wq_mayday_lock); |
| |
| /* rescuer will empty maydays list before exiting */ |
| kthread_stop(rescuer->task); |
| kfree(rescuer); |
| } |
| |
| /* |
| * Sanity checks - grab all the locks so that we wait for all |
| * in-flight operations which may do put_pwq(). |
| */ |
| mutex_lock(&wq_pool_mutex); |
| mutex_lock(&wq->mutex); |
| for_each_pwq(pwq, wq) { |
| raw_spin_lock_irq(&pwq->pool->lock); |
| if (WARN_ON(pwq_busy(pwq))) { |
| pr_warn("%s: %s has the following busy pwq\n", |
| __func__, wq->name); |
| show_pwq(pwq); |
| raw_spin_unlock_irq(&pwq->pool->lock); |
| mutex_unlock(&wq->mutex); |
| mutex_unlock(&wq_pool_mutex); |
| show_one_workqueue(wq); |
| return; |
| } |
| raw_spin_unlock_irq(&pwq->pool->lock); |
| } |
| mutex_unlock(&wq->mutex); |
| |
| /* |
| * wq list is used to freeze wq, remove from list after |
| * flushing is complete in case freeze races us. |
| */ |
| list_del_rcu(&wq->list); |
| mutex_unlock(&wq_pool_mutex); |
| |
| /* |
| * We're the sole accessor of @wq. Directly access cpu_pwq and dfl_pwq |
| * to put the base refs. @wq will be auto-destroyed from the last |
| * pwq_put. RCU read lock prevents @wq from going away from under us. |
| */ |
| rcu_read_lock(); |
| |
| for_each_possible_cpu(cpu) { |
| pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu)); |
| RCU_INIT_POINTER(*per_cpu_ptr(wq->cpu_pwq, cpu), NULL); |
| put_pwq_unlocked(pwq); |
| } |
| |
| put_pwq_unlocked(wq->dfl_pwq); |
| wq->dfl_pwq = NULL; |
| |
| rcu_read_unlock(); |
| } |
| EXPORT_SYMBOL_GPL(destroy_workqueue); |
| |
| /** |
| * workqueue_set_max_active - adjust max_active of a workqueue |
| * @wq: target workqueue |
| * @max_active: new max_active value. |
| * |
| * Set max_active of @wq to @max_active. |
| * |
| * CONTEXT: |
| * Don't call from IRQ context. |
| */ |
| void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) |
| { |
| struct pool_workqueue *pwq; |
| |
| /* disallow meddling with max_active for ordered workqueues */ |
| if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) |
| return; |
| |
| max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); |
| |
| mutex_lock(&wq->mutex); |
| |
| wq->flags &= ~__WQ_ORDERED; |
| wq->saved_max_active = max_active; |
| |
| for_each_pwq(pwq, wq) |
| pwq_adjust_max_active(pwq); |
| |
| mutex_unlock(&wq->mutex); |
| } |
| EXPORT_SYMBOL_GPL(workqueue_set_max_active); |
| |
| /** |
| * current_work - retrieve %current task's work struct |
| * |
| * Determine if %current task is a workqueue worker and what it's working on. |
| * Useful to find out the context that the %current task is running in. |
| * |
| * Return: work struct if %current task is a workqueue worker, %NULL otherwise. |
| */ |
| struct work_struct *current_work(void) |
| { |
| struct worker *worker = current_wq_worker(); |
| |
| return worker ? worker->current_work : NULL; |
| } |
| EXPORT_SYMBOL(current_work); |
| |
| /** |
| * current_is_workqueue_rescuer - is %current workqueue rescuer? |
| * |
| * Determine whether %current is a workqueue rescuer. Can be used from |
| * work functions to determine whether it's being run off the rescuer task. |
| * |
| * Return: %true if %current is a workqueue rescuer. %false otherwise. |
| */ |
| bool current_is_workqueue_rescuer(void) |
| { |
| struct worker *worker = current_wq_worker(); |
| |
| return worker && worker->rescue_wq; |
| } |
| |
| /** |
| * workqueue_congested - test whether a workqueue is congested |
| * @cpu: CPU in question |
| * @wq: target workqueue |
| * |
| * Test whether @wq's cpu workqueue for @cpu is congested. There is |
| * no synchronization around this function and the test result is |
| * unreliable and only useful as advisory hints or for debugging. |
| * |
| * If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU. |
| * |
| * With the exception of ordered workqueues, all workqueues have per-cpu |
| * pool_workqueues, each with its own congested state. A workqueue being |
| * congested on one CPU doesn't mean that the workqueue is contested on any |
| * other CPUs. |
| * |
| * Return: |
| * %true if congested, %false otherwise. |
| */ |
| bool workqueue_congested(int cpu, struct workqueue_struct *wq) |
| { |
| struct pool_workqueue *pwq; |
| bool ret; |
| |
| rcu_read_lock(); |
| preempt_disable(); |
| |
| if (cpu == WORK_CPU_UNBOUND) |
| cpu = smp_processor_id(); |
| |
| pwq = *per_cpu_ptr(wq->cpu_pwq, cpu); |
| ret = !list_empty(&pwq->inactive_works); |
| |
| preempt_enable(); |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(workqueue_congested); |
| |
| /** |
| * work_busy - test whether a work is currently pending or running |
| * @work: the work to be tested |
| * |
| * Test whether @work is currently pending or running. There is no |
| * synchronization around this function and the test result is |
| * unreliable and only useful as advisory hints or for debugging. |
| * |
| * Return: |
| * OR'd bitmask of WORK_BUSY_* bits. |
| */ |
| unsigned int work_busy(struct work_struct *work) |
| { |
| struct worker_pool *pool; |
| unsigned long flags; |
| unsigned int ret = 0; |
| |
| if (work_pending(work)) |
| ret |= WORK_BUSY_PENDING; |
| |
| rcu_read_lock(); |
| pool = get_work_pool(work); |
| if (pool) { |
| raw_spin_lock_irqsave(&pool->lock, flags); |
| if (find_worker_executing_work(pool, work)) |
| ret |= WORK_BUSY_RUNNING; |
| raw_spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(work_busy); |
| |
| /** |
| * set_worker_desc - set description for the current work item |
| * @fmt: printf-style format string |
| * @...: arguments for the format string |
| * |
| * This function can be called by a running work function to describe what |
| * the work item is about. If the worker task gets dumped, this |
| * information will be printed out together to help debugging. The |
| * description can be at most WORKER_DESC_LEN including the trailing '\0'. |
| */ |
| void set_worker_desc(const char *fmt, ...) |
| { |
| struct worker *worker = current_wq_worker(); |
| va_list args; |
| |
| if (worker) { |
| va_start(args, fmt); |
| vsnprintf(worker->desc, sizeof(worker->desc), fmt, args); |
| va_end(args); |
| } |
| } |
| EXPORT_SYMBOL_GPL(set_worker_desc); |
| |
| /** |
| * print_worker_info - print out worker information and description |
| * @log_lvl: the log level to use when printing |
| * @task: target task |
| * |
| * If @task is a worker and currently executing a work item, print out the |
| * name of the workqueue being serviced and worker description set with |
| * set_worker_desc() by the currently executing work item. |
| * |
| * This function can be safely called on any task as long as the |
| * task_struct itself is accessible. While safe, this function isn't |
| * synchronized and may print out mixups or garbages of limited length. |
| */ |
| void print_worker_info(const char *log_lvl, struct task_struct *task) |
| { |
| work_func_t *fn = NULL; |
| char name[WQ_NAME_LEN] = { }; |
| char desc[WORKER_DESC_LEN] = { }; |
| struct pool_workqueue *pwq = NULL; |
| struct workqueue_struct *wq = NULL; |
| struct worker *worker; |
| |
| if (!(task->flags & PF_WQ_WORKER)) |
| return; |
| |
| /* |
| * This function is called without any synchronization and @task |
| * could be in any state. Be careful with dereferences. |
| */ |
| worker = kthread_probe_data(task); |
| |
| /* |
| * Carefully copy the associated workqueue's workfn, name and desc. |
| * Keep the original last '\0' in case the original is garbage. |
| */ |
| copy_from_kernel_nofault(&fn, &worker->current_func, sizeof(fn)); |
| copy_from_kernel_nofault(&pwq, &worker->current_pwq, sizeof(pwq)); |
| copy_from_kernel_nofault(&wq, &pwq->wq, sizeof(wq)); |
| copy_from_kernel_nofault(name, wq->name, sizeof(name) - 1); |
| copy_from_kernel_nofault(desc, worker->desc, sizeof(desc) - 1); |
| |
| if (fn || name[0] || desc[0]) { |
| printk("%sWorkqueue: %s %ps", log_lvl, name, fn); |
| if (strcmp(name, desc)) |
| pr_cont(" (%s)", desc); |
| pr_cont("\n"); |
| } |
| } |
| |
| static void pr_cont_pool_info(struct worker_pool *pool) |
| { |
| pr_cont(" cpus=%*pbl", nr_cpumask_bits, pool->attrs->cpumask); |
| if (pool->node != NUMA_NO_NODE) |
| pr_cont(" node=%d", pool->node); |
| pr_cont(" flags=0x%x nice=%d", pool->flags, pool->attrs->nice); |
| } |
| |
| struct pr_cont_work_struct { |
| bool comma; |
| work_func_t func; |
| long ctr; |
| }; |
| |
| static void pr_cont_work_flush(bool comma, work_func_t func, struct pr_cont_work_struct *pcwsp) |
| { |
| if (!pcwsp->ctr) |
| goto out_record; |
| if (func == pcwsp->func) { |
| pcwsp->ctr++; |
| return; |
| } |
| if (pcwsp->ctr == 1) |
| pr_cont("%s %ps", pcwsp->comma ? "," : "", pcwsp->func); |
| else |
| pr_cont("%s %ld*%ps", pcwsp->comma ? "," : "", pcwsp->ctr, pcwsp->func); |
| pcwsp->ctr = 0; |
| out_record: |
| if ((long)func == -1L) |
| return; |
| pcwsp->comma = comma; |
| pcwsp->func = func; |
| pcwsp->ctr = 1; |
| } |
| |
| static void pr_cont_work(bool comma, struct work_struct *work, struct pr_cont_work_struct *pcwsp) |
| { |
| if (work->func == wq_barrier_func) { |
| struct wq_barrier *barr; |
| |
| barr = container_of(work, struct wq_barrier, work); |
| |
| pr_cont_work_flush(comma, (work_func_t)-1, pcwsp); |
| pr_cont("%s BAR(%d)", comma ? "," : "", |
| task_pid_nr(barr->task)); |
| } else { |
| if (!comma) |
| pr_cont_work_flush(comma, (work_func_t)-1, pcwsp); |
| pr_cont_work_flush(comma, work->func, pcwsp); |
| } |
| } |
| |
| static void show_pwq(struct pool_workqueue *pwq) |
| { |
| struct pr_cont_work_struct pcws = { .ctr = 0, }; |
| struct worker_pool *pool = pwq->pool; |
| struct work_struct *work; |
| struct worker *worker; |
| bool has_in_flight = false, has_pending = false; |
| int bkt; |
| |
| pr_info(" pwq %d:", pool->id); |
| pr_cont_pool_info(pool); |
| |
| pr_cont(" active=%d/%d refcnt=%d%s\n", |
| pwq->nr_active, pwq->max_active, pwq->refcnt, |
| !list_empty(&pwq->mayday_node) ? " MAYDAY" : ""); |
| |
| hash_for_each(pool->busy_hash, bkt, worker, hentry) { |
| if (worker->current_pwq == pwq) { |
| has_in_flight = true; |
| break; |
| } |
| } |
| if (has_in_flight) { |
| bool comma = false; |
| |
| pr_info(" in-flight:"); |
| hash_for_each(pool->busy_hash, bkt, worker, hentry) { |
| if (worker->current_pwq != pwq) |
| continue; |
| |
| pr_cont("%s %d%s:%ps", comma ? "," : "", |
| task_pid_nr(worker->task), |
| worker->rescue_wq ? "(RESCUER)" : "", |
| worker->current_func); |
| list_for_each_entry(work, &worker->scheduled, entry) |
| pr_cont_work(false, work, &pcws); |
| pr_cont_work_flush(comma, (work_func_t)-1L, &pcws); |
| comma = true; |
| } |
| pr_cont("\n"); |
| } |
| |
| list_for_each_entry(work, &pool->worklist, entry) { |
| if (get_work_pwq(work) == pwq) { |
| has_pending = true; |
| break; |
| } |
| } |
| if (has_pending) { |
| bool comma = false; |
| |
| pr_info(" pending:"); |
| list_for_each_entry(work, &pool->worklist, entry) { |
| if (get_work_pwq(work) != pwq) |
| continue; |
| |
| pr_cont_work(comma, work, &pcws); |
| comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED); |
| } |
| pr_cont_work_flush(comma, (work_func_t)-1L, &pcws); |
| pr_cont("\n"); |
| } |
| |
| if (!list_empty(&pwq->inactive_works)) { |
| bool comma = false; |
| |
| pr_info(" inactive:"); |
| list_for_each_entry(work, &pwq->inactive_works, entry) { |
| pr_cont_work(comma, work, &pcws); |
| comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED); |
| } |
| pr_cont_work_flush(comma, (work_func_t)-1L, &pcws); |
| pr_cont("\n"); |
| } |
| } |
| |
| /** |
| * show_one_workqueue - dump state of specified workqueue |
| * @wq: workqueue whose state will be printed |
| */ |
| void show_one_workqueue(struct workqueue_struct *wq) |
| { |
| struct pool_workqueue *pwq; |
| bool idle = true; |
| unsigned long flags; |
| |
| for_each_pwq(pwq, wq) { |
| if (pwq->nr_active || !list_empty(&pwq->inactive_works)) { |
| idle = false; |
| break; |
| } |
| } |
| if (idle) /* Nothing to print for idle workqueue */ |
| return; |
| |
| pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags); |
| |
| for_each_pwq(pwq, wq) { |
| raw_spin_lock_irqsave(&pwq->pool->lock, flags); |
| if (pwq->nr_active || !list_empty(&pwq->inactive_works)) { |
| /* |
| * Defer printing to avoid deadlocks in console |
| * drivers that queue work while holding locks |
| * also taken in their write paths. |
| */ |
| printk_deferred_enter(); |
| show_pwq(pwq); |
| printk_deferred_exit(); |
| } |
| raw_spin_unlock_irqrestore(&pwq->pool->lock, flags); |
| /* |
| * We could be printing a lot from atomic context, e.g. |
| * sysrq-t -> show_all_workqueues(). Avoid triggering |
| * hard lockup. |
| */ |
| touch_nmi_watchdog(); |
| } |
| |
| } |
| |
| /** |
| * show_one_worker_pool - dump state of specified worker pool |
| * @pool: worker pool whose state will be printed |
| */ |
| static void show_one_worker_pool(struct worker_pool *pool) |
| { |
| struct worker *worker; |
| bool first = true; |
| unsigned long flags; |
| unsigned long hung = 0; |
| |
| raw_spin_lock_irqsave(&pool->lock, flags); |
| if (pool->nr_workers == pool->nr_idle) |
| goto next_pool; |
| |
| /* How long the first pending work is waiting for a worker. */ |
| if (!list_empty(&pool->worklist)) |
| hung = jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000; |
| |
| /* |
| * Defer printing to avoid deadlocks in console drivers that |
| * queue work while holding locks also taken in their write |
| * paths. |
| */ |
| printk_deferred_enter(); |
| pr_info("pool %d:", pool->id); |
| pr_cont_pool_info(pool); |
| pr_cont(" hung=%lus workers=%d", hung, pool->nr_workers); |
| if (pool->manager) |
| pr_cont(" manager: %d", |
| task_pid_nr(pool->manager->task)); |
| list_for_each_entry(worker, &pool->idle_list, entry) { |
| pr_cont(" %s%d", first ? "idle: " : "", |
| task_pid_nr(worker->task)); |
| first = false; |
| } |
| pr_cont("\n"); |
| printk_deferred_exit(); |
| next_pool: |
| raw_spin_unlock_irqrestore(&pool->lock, flags); |
| /* |
| * We could be printing a lot from atomic context, e.g. |
| * sysrq-t -> show_all_workqueues(). Avoid triggering |
| * hard lockup. |
| */ |
| touch_nmi_watchdog(); |
| |
| } |
| |
| /** |
| * show_all_workqueues - dump workqueue state |
| * |
| * Called from a sysrq handler and prints out all busy workqueues and pools. |
| */ |
| void show_all_workqueues(void) |
| { |
| struct workqueue_struct *wq; |
| struct worker_pool *pool; |
| int pi; |
| |
| rcu_read_lock(); |
| |
| pr_info("Showing busy workqueues and worker pools:\n"); |
| |
| list_for_each_entry_rcu(wq, &workqueues, list) |
| show_one_workqueue(wq); |
| |
| for_each_pool(pool, pi) |
| show_one_worker_pool(pool); |
| |
| rcu_read_unlock(); |
| } |
| |
| /** |
| * show_freezable_workqueues - dump freezable workqueue state |
| * |
| * Called from try_to_freeze_tasks() and prints out all freezable workqueues |
| * still busy. |
| */ |
| void show_freezable_workqueues(void) |
| { |
| struct workqueue_struct *wq; |
| |
| rcu_read_lock(); |
| |
| pr_info("Showing freezable workqueues that are still busy:\n"); |
| |
| list_for_each_entry_rcu(wq, &workqueues, list) { |
| if (!(wq->flags & WQ_FREEZABLE)) |
| continue; |
| show_one_workqueue(wq); |
| } |
| |
| rcu_read_unlock(); |
| } |
| |
| /* used to show worker information through /proc/PID/{comm,stat,status} */ |
| void wq_worker_comm(char *buf, size_t size, struct task_struct *task) |
| { |
| int off; |
| |
| /* always show the actual comm */ |
| off = strscpy(buf, task->comm, size); |
| if (off < 0) |
| return; |
| |
| /* stabilize PF_WQ_WORKER and worker pool association */ |
| mutex_lock(&wq_pool_attach_mutex); |
| |
| if (task->flags & PF_WQ_WORKER) { |
| struct worker *worker = kthread_data(task); |
| struct worker_pool *pool = worker->pool; |
| |
| if (pool) { |
| raw_spin_lock_irq(&pool->lock); |
| /* |
| * ->desc tracks information (wq name or |
| * set_worker_desc()) for the latest execution. If |
| * current, prepend '+', otherwise '-'. |
| */ |
| if (worker->desc[0] != '\0') { |
| if (worker->current_work) |
| scnprintf(buf + off, size - off, "+%s", |
| worker->desc); |
| else |
| scnprintf(buf + off, size - off, "-%s", |
| worker->desc); |
| } |
| raw_spin_unlock_irq(&pool->lock); |
| } |
| } |
| |
| mutex_unlock(&wq_pool_attach_mutex); |
| } |
| |
| #ifdef CONFIG_SMP |
| |
| /* |
| * CPU hotplug. |
| * |
| * There are two challenges in supporting CPU hotplug. Firstly, there |
| * are a lot of assumptions on strong associations among work, pwq and |
| * pool which make migrating pending and scheduled works very |
| * difficult to implement without impacting hot paths. Secondly, |
| * worker pools serve mix of short, long and very long running works making |
| * blocked draining impractical. |
| * |
| * This is solved by allowing the pools to be disassociated from the CPU |
| * running as an unbound one and allowing it to be reattached later if the |
| * cpu comes back online. |
| */ |
| |
| static void unbind_workers(int cpu) |
| { |
| struct worker_pool *pool; |
| struct worker *worker; |
| |
| for_each_cpu_worker_pool(pool, cpu) { |
| mutex_lock(&wq_pool_attach_mutex); |
| raw_spin_lock_irq(&pool->lock); |
| |
| /* |
| * We've blocked all attach/detach operations. Make all workers |
| * unbound and set DISASSOCIATED. Before this, all workers |
| * must be on the cpu. After this, they may become diasporas. |
| * And the preemption disabled section in their sched callbacks |
| * are guaranteed to see WORKER_UNBOUND since the code here |
| * is on the same cpu. |
| */ |
| for_each_pool_worker(worker, pool) |
| worker->flags |= WORKER_UNBOUND; |
| |
| pool->flags |= POOL_DISASSOCIATED; |
| |
| /* |
| * The handling of nr_running in sched callbacks are disabled |
| * now. Zap nr_running. After this, nr_running stays zero and |
| * need_more_worker() and keep_working() are always true as |
| * long as the worklist is not empty. This pool now behaves as |
| * an unbound (in terms of concurrency management) pool which |
| * are served by workers tied to the pool. |
| */ |
| pool->nr_running = 0; |
| |
| /* |
| * With concurrency management just turned off, a busy |
| * worker blocking could lead to lengthy stalls. Kick off |
| * unbound chain execution of currently pending work items. |
| */ |
| kick_pool(pool); |
| |
| raw_spin_unlock_irq(&pool->lock); |
| |
| for_each_pool_worker(worker, pool) |
| unbind_worker(worker); |
| |
| mutex_unlock(&wq_pool_attach_mutex); |
| } |
| } |
| |
| /** |
| * rebind_workers - rebind all workers of a pool to the associated CPU |
| * @pool: pool of interest |
| * |
| * @pool->cpu is coming online. Rebind all workers to the CPU. |
| */ |
| static void rebind_workers(struct worker_pool *pool) |
| { |
| struct worker *worker; |
| |
| lockdep_assert_held(&wq_pool_attach_mutex); |
| |
| /* |
| * Restore CPU affinity of all workers. As all idle workers should |
| * be on the run-queue of the associated CPU before any local |
| * wake-ups for concurrency management happen, restore CPU affinity |
| * of all workers first and then clear UNBOUND. As we're called |
| * from CPU_ONLINE, the following shouldn't fail. |
| */ |
| for_each_pool_worker(worker, pool) { |
| kthread_set_per_cpu(worker->task, pool->cpu); |
| WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, |
| pool_allowed_cpus(pool)) < 0); |
| } |
| |
| raw_spin_lock_irq(&pool->lock); |
| |
| pool->flags &= ~POOL_DISASSOCIATED; |
| |
| for_each_pool_worker(worker, pool) { |
| unsigned int worker_flags = worker->flags; |
| |
| /* |
| * We want to clear UNBOUND but can't directly call |
| * worker_clr_flags() or adjust nr_running. Atomically |
| * replace UNBOUND with another NOT_RUNNING flag REBOUND. |
| * @worker will clear REBOUND using worker_clr_flags() when |
| * it initiates the next execution cycle thus restoring |
| * concurrency management. Note that when or whether |
| * @worker clears REBOUND doesn't affect correctness. |
| * |
| * WRITE_ONCE() is necessary because @worker->flags may be |
| * tested without holding any lock in |
| * wq_worker_running(). Without it, NOT_RUNNING test may |
| * fail incorrectly leading to premature concurrency |
| * management operations. |
| */ |
| WARN_ON_ONCE(!(worker_flags & WORKER_UNBOUND)); |
| worker_flags |= WORKER_REBOUND; |
| worker_flags &= ~WORKER_UNBOUND; |
| WRITE_ONCE(worker->flags, worker_flags); |
| } |
| |
| raw_spin_unlock_irq(&pool->lock); |
| } |
| |
| /** |
| * restore_unbound_workers_cpumask - restore cpumask of unbound workers |
| * @pool: unbound pool of interest |
| * @cpu: the CPU which is coming up |
| * |
| * An unbound pool may end up with a cpumask which doesn't have any online |
| * CPUs. When a worker of such pool get scheduled, the scheduler resets |
| * its cpus_allowed. If @cpu is in @pool's cpumask which didn't have any |
| * online CPU before, cpus_allowed of all its workers should be restored. |
| */ |
| static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu) |
| { |
| static cpumask_t cpumask; |
| struct worker *worker; |
| |
| lockdep_assert_held(&wq_pool_attach_mutex); |
| |
| /* is @cpu allowed for @pool? */ |
| if (!cpumask_test_cpu(cpu, pool->attrs->cpumask)) |
| return; |
| |
| cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask); |
| |
| /* as we're called from CPU_ONLINE, the following shouldn't fail */ |
| for_each_pool_worker(worker, pool) |
| WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, &cpumask) < 0); |
| } |
| |
| int workqueue_prepare_cpu(unsigned int cpu) |
| { |
| struct worker_pool *pool; |
| |
| for_each_cpu_worker_pool(pool, cpu) { |
| if (pool->nr_workers) |
| continue; |
| if (!create_worker(pool)) |
| return -ENOMEM; |
| } |
| return 0; |
| } |
| |
| int workqueue_online_cpu(unsigned int cpu) |
| { |
| struct worker_pool *pool; |
| struct workqueue_struct *wq; |
| int pi; |
| |
| mutex_lock(&wq_pool_mutex); |
| |
| for_each_pool(pool, pi) { |
| mutex_lock(&wq_pool_attach_mutex); |
| |
| if (pool->cpu == cpu) |
| rebind_workers(pool); |
| else if (pool->cpu < 0) |
| restore_unbound_workers_cpumask(pool, cpu); |
| |
| mutex_unlock(&wq_pool_attach_mutex); |
| } |
| |
| /* update pod affinity of unbound workqueues */ |
| list_for_each_entry(wq, &workqueues, list) { |
| struct workqueue_attrs *attrs = wq->unbound_attrs; |
| |
| if (attrs) { |
| const struct wq_pod_type *pt = wqattrs_pod_type(attrs); |
| int tcpu; |
| |
| for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]]) |
| wq_update_pod(wq, tcpu, cpu, true); |
| } |
| } |
| |
| mutex_unlock(&wq_pool_mutex); |
| return 0; |
| } |
| |
| int workqueue_offline_cpu(unsigned int cpu) |
| { |
| struct workqueue_struct *wq; |
| |
| /* unbinding per-cpu workers should happen on the local CPU */ |
| if (WARN_ON(cpu != smp_processor_id())) |
| return -1; |
| |
| unbind_workers(cpu); |
| |
| /* update pod affinity of unbound workqueues */ |
| mutex_lock(&wq_pool_mutex); |
| list_for_each_entry(wq, &workqueues, list) { |
| struct workqueue_attrs *attrs = wq->unbound_attrs; |
| |
| if (attrs) { |
| const struct wq_pod_type *pt = wqattrs_pod_type(attrs); |
| int tcpu; |
| |
| for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]]) |
| wq_update_pod(wq, tcpu, cpu, false); |
| } |
| } |
| mutex_unlock(&wq_pool_mutex); |
| |
| return 0; |
| } |
| |
| struct work_for_cpu { |
| struct work_struct work; |
| long (*fn)(void *); |
| void *arg; |
| long ret; |
| }; |
| |
| static void work_for_cpu_fn(struct work_struct *work) |
| { |
| struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work); |
| |
| wfc->ret = wfc->fn(wfc->arg); |
| } |
| |
| /** |
| * work_on_cpu - run a function in thread context on a particular cpu |
| * @cpu: the cpu to run on |
| * @fn: the function to run |
| * @arg: the function arg |
| * |
| * It is up to the caller to ensure that the cpu doesn't go offline. |
| * The caller must not hold any locks which would prevent @fn from completing. |
| * |
| * Return: The value @fn returns. |
| */ |
| long work_on_cpu(int cpu, long (*fn)(void *), void *arg) |
| { |
| struct work_for_cpu wfc = { .fn = fn, .arg = arg }; |
| |
| INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn); |
| schedule_work_on(cpu, &wfc.work); |
| flush_work(&wfc.work); |
| destroy_work_on_stack(&wfc.work); |
| return wfc.ret; |
| } |
| EXPORT_SYMBOL_GPL(work_on_cpu); |
| |
| /** |
| * work_on_cpu_safe - run a function in thread context on a particular cpu |
| * @cpu: the cpu to run on |
| * @fn: the function to run |
| * @arg: the function argument |
| * |
| * Disables CPU hotplug and calls work_on_cpu(). The caller must not hold |
| * any locks which would prevent @fn from completing. |
| * |
| * Return: The value @fn returns. |
| */ |
| long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg) |
| { |
| long ret = -ENODEV; |
| |
| cpus_read_lock(); |
| if (cpu_online(cpu)) |
| ret = work_on_cpu(cpu, fn, arg); |
| cpus_read_unlock(); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(work_on_cpu_safe); |
| #endif /* CONFIG_SMP */ |
| |
| #ifdef CONFIG_FREEZER |
| |
| /** |
| * freeze_workqueues_begin - begin freezing workqueues |
| * |
| * Start freezing workqueues. After this function returns, all freezable |
| * workqueues will queue new works to their inactive_works list instead of |
| * pool->worklist. |
| * |
| * CONTEXT: |
| * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's. |
| */ |
| void freeze_workqueues_begin(void) |
| { |
| struct workqueue_struct *wq; |
| struct pool_workqueue *pwq; |
| |
| mutex_lock(&wq_pool_mutex); |
| |
| WARN_ON_ONCE(workqueue_freezing); |
| workqueue_freezing = true; |
| |
| list_for_each_entry(wq, &workqueues, list) { |
| mutex_lock(&wq->mutex); |
| for_each_pwq(pwq, wq) |
| pwq_adjust_max_active(pwq); |
| mutex_unlock(&wq->mutex); |
| } |
| |
| mutex_unlock(&wq_pool_mutex); |
| } |
| |
| /** |
| * freeze_workqueues_busy - are freezable workqueues still busy? |
| * |
| * Check whether freezing is complete. This function must be called |
| * between freeze_workqueues_begin() and thaw_workqueues(). |
| * |
| * CONTEXT: |
| * Grabs and releases wq_pool_mutex. |
| * |
| * Return: |
| * %true if some freezable workqueues are still busy. %false if freezing |
| * is complete. |
| */ |
| bool freeze_workqueues_busy(void) |
| { |
| bool busy = false; |
| struct workqueue_struct *wq; |
| struct pool_workqueue *pwq; |
| |
| mutex_lock(&wq_pool_mutex); |
| |
| WARN_ON_ONCE(!workqueue_freezing); |
| |
| list_for_each_entry(wq, &workqueues, list) { |
| if (!(wq->flags & WQ_FREEZABLE)) |
| continue; |
| /* |
| * nr_active is monotonically decreasing. It's safe |
| * to peek without lock. |
| */ |
| rcu_read_lock(); |
| for_each_pwq(pwq, wq) { |
| WARN_ON_ONCE(pwq->nr_active < 0); |
| if (pwq->nr_active) { |
| busy = true; |
| rcu_read_unlock(); |
| goto out_unlock; |
| } |
| } |
| rcu_read_unlock(); |
| } |
| out_unlock: |
| mutex_unlock(&wq_pool_mutex); |
| return busy; |
| } |
| |
| /** |
| * thaw_workqueues - thaw workqueues |
| * |
| * Thaw workqueues. Normal queueing is restored and all collected |
| * frozen works are transferred to their respective pool worklists. |
| * |
| * CONTEXT: |
| * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's. |
| */ |
| void thaw_workqueues(void) |
| { |
| struct workqueue_struct *wq; |
| struct pool_workqueue *pwq; |
| |
| mutex_lock(&wq_pool_mutex); |
| |
| if (!workqueue_freezing) |
| goto out_unlock; |
| |
| workqueue_freezing = false; |
| |
| /* restore max_active and repopulate worklist */ |
| list_for_each_entry(wq, &workqueues, list) { |
| mutex_lock(&wq->mutex); |
| for_each_pwq(pwq, wq) |
| pwq_adjust_max_active(pwq); |
| mutex_unlock(&wq->mutex); |
| } |
| |
| out_unlock: |
| mutex_unlock(&wq_pool_mutex); |
| } |
| #endif /* CONFIG_FREEZER */ |
| |
| static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask) |
| { |
| LIST_HEAD(ctxs); |
| int ret = 0; |
| struct workqueue_struct *wq; |
| struct apply_wqattrs_ctx *ctx, *n; |
| |
| lockdep_assert_held(&wq_pool_mutex); |
| |
| list_for_each_entry(wq, &workqueues, list) { |
| if (!(wq->flags & WQ_UNBOUND)) |
| continue; |
| |
| /* creating multiple pwqs breaks ordering guarantee */ |
| if (!list_empty(&wq->pwqs)) { |
| if (wq->flags & __WQ_ORDERED_EXPLICIT) |
| continue; |
| wq->flags &= ~__WQ_ORDERED; |
| } |
| |
| ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs, unbound_cpumask); |
| if (IS_ERR(ctx)) { |
| ret = PTR_ERR(ctx); |
| break; |
| } |
| |
| list_add_tail(&ctx->list, &ctxs); |
| } |
| |
| list_for_each_entry_safe(ctx, n, &ctxs, list) { |
| if (!ret) |
| apply_wqattrs_commit(ctx); |
| apply_wqattrs_cleanup(ctx); |
| } |
| |
| if (!ret) { |
| mutex_lock(&wq_pool_attach_mutex); |
| cpumask_copy(wq_unbound_cpumask, unbound_cpumask); |
| mutex_unlock(&wq_pool_attach_mutex); |
| } |
| return ret; |
| } |
| |
| /** |
| * workqueue_set_unbound_cpumask - Set the low-level unbound cpumask |
| * @cpumask: the cpumask to set |
| * |
| * The low-level workqueues cpumask is a global cpumask that limits |
| * the affinity of all unbound workqueues. This function check the @cpumask |
| * and apply it to all unbound workqueues and updates all pwqs of them. |
| * |
| * Return: 0 - Success |
| * -EINVAL - Invalid @cpumask |
| * -ENOMEM - Failed to allocate memory for attrs or pwqs. |
| */ |
| int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) |
| { |
| int ret = -EINVAL; |
| |
| /* |
| * Not excluding isolated cpus on purpose. |
| * If the user wishes to include them, we allow that. |
| */ |
| cpumask_and(cpumask, cpumask, cpu_possible_mask); |
| if (!cpumask_empty(cpumask)) { |
| apply_wqattrs_lock(); |
| if (cpumask_equal(cpumask, wq_unbound_cpumask)) { |
| ret = 0; |
| goto out_unlock; |
| } |
| |
| ret = workqueue_apply_unbound_cpumask(cpumask); |
| |
| out_unlock: |
| apply_wqattrs_unlock(); |
| } |
| |
| return ret; |
| } |
| |
| static int parse_affn_scope(const char *val) |
| { |
| int i; |
| |
| for (i = 0; i < ARRAY_SIZE(wq_affn_names); i++) { |
| if (!strncasecmp(val, wq_affn_names[i], strlen(wq_affn_names[i]))) |
| return i; |
| } |
| return -EINVAL; |
| } |
| |
| static int wq_affn_dfl_set(const char *val, const struct kernel_param *kp) |
| { |
| struct workqueue_struct *wq; |
| int affn, cpu; |
| |
| affn = parse_affn_scope(val); |
| if (affn < 0) |
| return affn; |
| if (affn == WQ_AFFN_DFL) |
| return -EINVAL; |
| |
| cpus_read_lock(); |
| mutex_lock(&wq_pool_mutex); |
| |
| wq_affn_dfl = affn; |
| |
| list_for_each_entry(wq, &workqueues, list) { |
| for_each_online_cpu(cpu) { |
| wq_update_pod(wq, cpu, cpu, true); |
| } |
| } |
| |
| mutex_unlock(&wq_pool_mutex); |
| cpus_read_unlock(); |
| |
| return 0; |
| } |
| |
| static int wq_affn_dfl_get(char *buffer, const struct kernel_param *kp) |
| { |
| return scnprintf(buffer, PAGE_SIZE, "%s\n", wq_affn_names[wq_affn_dfl]); |
| } |
| |
| static const struct kernel_param_ops wq_affn_dfl_ops = { |
| .set = wq_affn_dfl_set, |
| .get = wq_affn_dfl_get, |
| }; |
| |
| module_param_cb(default_affinity_scope, &wq_affn_dfl_ops, NULL, 0644); |
| |
| #ifdef CONFIG_SYSFS |
| /* |
| * Workqueues with WQ_SYSFS flag set is visible to userland via |
| * /sys/bus/workqueue/devices/WQ_NAME. All visible workqueues have the |
| * following attributes. |
| * |
| * per_cpu RO bool : whether the workqueue is per-cpu or unbound |
| * max_active RW int : maximum number of in-flight work items |
| * |
| * Unbound workqueues have the following extra attributes. |
| * |
| * nice RW int : nice value of the workers |
| * cpumask RW mask : bitmask of allowed CPUs for the workers |
| * affinity_scope RW str : worker CPU affinity scope (cache, numa, none) |
| * affinity_strict RW bool : worker CPU affinity is strict |
| */ |
| struct wq_device { |
| struct workqueue_struct *wq; |
| struct device dev; |
| }; |
| |
| static struct workqueue_struct *dev_to_wq(struct device *dev) |
| { |
| struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); |
| |
| return wq_dev->wq; |
| } |
| |
| static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr, |
| char *buf) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| |
| return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND)); |
| } |
| static DEVICE_ATTR_RO(per_cpu); |
| |
| static ssize_t max_active_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| |
| return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active); |
| } |
| |
| static ssize_t max_active_store(struct device *dev, |
| struct device_attribute *attr, const char *buf, |
| size_t count) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| int val; |
| |
| if (sscanf(buf, "%d", &val) != 1 || val <= 0) |
| return -EINVAL; |
| |
| workqueue_set_max_active(wq, val); |
| return count; |
| } |
| static DEVICE_ATTR_RW(max_active); |
| |
| static struct attribute *wq_sysfs_attrs[] = { |
| &dev_attr_per_cpu.attr, |
| &dev_attr_max_active.attr, |
| NULL, |
| }; |
| ATTRIBUTE_GROUPS(wq_sysfs); |
| |
| static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr, |
| char *buf) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| int written; |
| |
| mutex_lock(&wq->mutex); |
| written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice); |
| mutex_unlock(&wq->mutex); |
| |
| return written; |
| } |
| |
| /* prepare workqueue_attrs for sysfs store operations */ |
| static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq) |
| { |
| struct workqueue_attrs *attrs; |
| |
| lockdep_assert_held(&wq_pool_mutex); |
| |
| attrs = alloc_workqueue_attrs(); |
| if (!attrs) |
| return NULL; |
| |
| copy_workqueue_attrs(attrs, wq->unbound_attrs); |
| return attrs; |
| } |
| |
| static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| struct workqueue_attrs *attrs; |
| int ret = -ENOMEM; |
| |
| apply_wqattrs_lock(); |
| |
| attrs = wq_sysfs_prep_attrs(wq); |
| if (!attrs) |
| goto out_unlock; |
| |
| if (sscanf(buf, "%d", &attrs->nice) == 1 && |
| attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE) |
| ret = apply_workqueue_attrs_locked(wq, attrs); |
| else |
| ret = -EINVAL; |
| |
| out_unlock: |
| apply_wqattrs_unlock(); |
| free_workqueue_attrs(attrs); |
| return ret ?: count; |
| } |
| |
| static ssize_t wq_cpumask_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| int written; |
| |
| mutex_lock(&wq->mutex); |
| written = scnprintf(buf, PAGE_SIZE, "%*pb\n", |
| cpumask_pr_args(wq->unbound_attrs->cpumask)); |
| mutex_unlock(&wq->mutex); |
| return written; |
| } |
| |
| static ssize_t wq_cpumask_store(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| struct workqueue_attrs *attrs; |
| int ret = -ENOMEM; |
| |
| apply_wqattrs_lock(); |
| |
| attrs = wq_sysfs_prep_attrs(wq); |
| if (!attrs) |
| goto out_unlock; |
| |
| ret = cpumask_parse(buf, attrs->cpumask); |
| if (!ret) |
| ret = apply_workqueue_attrs_locked(wq, attrs); |
| |
| out_unlock: |
| apply_wqattrs_unlock(); |
| free_workqueue_attrs(attrs); |
| return ret ?: count; |
| } |
| |
| static ssize_t wq_affn_scope_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| int written; |
| |
| mutex_lock(&wq->mutex); |
| if (wq->unbound_attrs->affn_scope == WQ_AFFN_DFL) |
| written = scnprintf(buf, PAGE_SIZE, "%s (%s)\n", |
| wq_affn_names[WQ_AFFN_DFL], |
| wq_affn_names[wq_affn_dfl]); |
| else |
| written = scnprintf(buf, PAGE_SIZE, "%s\n", |
| wq_affn_names[wq->unbound_attrs->affn_scope]); |
| mutex_unlock(&wq->mutex); |
| |
| return written; |
| } |
| |
| static ssize_t wq_affn_scope_store(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| struct workqueue_attrs *attrs; |
| int affn, ret = -ENOMEM; |
| |
| affn = parse_affn_scope(buf); |
| if (affn < 0) |
| return affn; |
| |
| apply_wqattrs_lock(); |
| attrs = wq_sysfs_prep_attrs(wq); |
| if (attrs) { |
| attrs->affn_scope = affn; |
| ret = apply_workqueue_attrs_locked(wq, attrs); |
| } |
| apply_wqattrs_unlock(); |
| free_workqueue_attrs(attrs); |
| return ret ?: count; |
| } |
| |
| static ssize_t wq_affinity_strict_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| |
| return scnprintf(buf, PAGE_SIZE, "%d\n", |
| wq->unbound_attrs->affn_strict); |
| } |
| |
| static ssize_t wq_affinity_strict_store(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct workqueue_struct *wq = dev_to_wq(dev); |
| struct workqueue_attrs *attrs; |
| int v, ret = -ENOMEM; |
| |
| if (sscanf(buf, "%d", &v) != 1) |
| return -EINVAL; |
| |
| apply_wqattrs_lock(); |
| attrs = wq_sysfs_prep_attrs(wq); |
| if (attrs) { |
| attrs->affn_strict = (bool)v; |
| ret = apply_workqueue_attrs_locked(wq, attrs); |
| } |
| apply_wqattrs_unlock(); |
| free_workqueue_attrs(attrs); |
| return ret ?: count; |
| } |
| |
| static struct device_attribute wq_sysfs_unbound_attrs[] = { |
| __ATTR(nice, 0644, wq_nice_show, wq_nice_store), |
| __ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store), |
| __ATTR(affinity_scope, 0644, wq_affn_scope_show, wq_affn_scope_store), |
| __ATTR(affinity_strict, 0644, wq_affinity_strict_show, wq_affinity_strict_store), |
| __ATTR_NULL, |
| }; |
| |
| static struct bus_type wq_subsys = { |
| .name = "workqueue", |
| .dev_groups = wq_sysfs_groups, |
| }; |
| |
| static ssize_t wq_unbound_cpumask_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| int written; |
| |
| mutex_lock(&wq_pool_mutex); |
| written = scnprintf(buf, PAGE_SIZE, "%*pb\n", |
| cpumask_pr_args(wq_unbound_cpumask)); |
| mutex_unlock(&wq_pool_mutex); |
| |
| return written; |
| } |
| |
| static ssize_t wq_unbound_cpumask_store(struct device *dev, |
| struct device_attribute *attr, const char *buf, size_t count) |
| { |
| cpumask_var_t cpumask; |
| int ret; |
| |
| if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL)) |
| return -ENOMEM; |
| |
| ret = cpumask_parse(buf, cpumask); |
| if (!ret) |
| ret = workqueue_set_unbound_cpumask(cpumask); |
| |
| free_cpumask_var(cpumask); |
| return ret ? ret : count; |
| } |
| |
| static struct device_attribute wq_sysfs_cpumask_attr = |
| __ATTR(cpumask, 0644, wq_unbound_cpumask_show, |
| wq_unbound_cpumask_store); |
| |
| static int __init wq_sysfs_init(void) |
| { |
| struct device *dev_root; |
| int err; |
| |
| err = subsys_virtual_register(&wq_subsys, NULL); |
| if (err) |
| return err; |
| |
| dev_root = bus_get_dev_root(&wq_subsys); |
| if (dev_root) { |
| err = device_create_file(dev_root, &wq_sysfs_cpumask_attr); |
| put_device(dev_root); |
| } |
| return err; |
| } |
| core_initcall(wq_sysfs_init); |
| |
| static void wq_device_release(struct device *dev) |
| { |
| struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); |
| |
| kfree(wq_dev); |
| } |
| |
| /** |
| * workqueue_sysfs_register - make a workqueue visible in sysfs |
| * @wq: the workqueue to register |
| * |
| * Expose @wq in sysfs under /sys/bus/workqueue/devices. |
| * alloc_workqueue*() automatically calls this function if WQ_SYSFS is set |
| * which is the preferred method. |
| * |
| * Workqueue user should use this function directly iff it wants to apply |
| * workqueue_attrs before making the workqueue visible in sysfs; otherwise, |
| * apply_workqueue_attrs() may race against userland updating the |
| * attributes. |
| * |
| * Return: 0 on success, -errno on failure. |
| */ |
| int workqueue_sysfs_register(struct workqueue_struct *wq) |
| { |
| struct wq_device *wq_dev; |
| int ret; |
| |
| /* |
| * Adjusting max_active or creating new pwqs by applying |
| * attributes breaks ordering guarantee. Disallow exposing ordered |
| * workqueues. |
| */ |
| if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) |
| return -EINVAL; |
| |
| wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL); |
| if (!wq_dev) |
| return -ENOMEM; |
| |
| wq_dev->wq = wq; |
| wq_dev->dev.bus = &wq_subsys; |
| wq_dev->dev.release = wq_device_release; |
| dev_set_name(&wq_dev->dev, "%s", wq->name); |
| |
| /* |
| * unbound_attrs are created separately. Suppress uevent until |
| * everything is ready. |
| */ |
| dev_set_uevent_suppress(&wq_dev->dev, true); |
| |
| ret = device_register(&wq_dev->dev); |
| if (ret) { |
| put_device(&wq_dev->dev); |
| wq->wq_dev = NULL; |
| return ret; |
| } |
| |
| if (wq->flags & WQ_UNBOUND) { |
| struct device_attribute *attr; |
| |
| for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) { |
| ret = device_create_file(&wq_dev->dev, attr); |
| if (ret) { |
| device_unregister(&wq_dev->dev); |
| wq->wq_dev = NULL; |
| return ret; |
| } |
| } |
| } |
| |
| dev_set_uevent_suppress(&wq_dev->dev, false); |
| kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD); |
| return 0; |
| } |
| |
| /** |
| * workqueue_sysfs_unregister - undo workqueue_sysfs_register() |
| * @wq: the workqueue to unregister |
| * |
| * If @wq is registered to sysfs by workqueue_sysfs_register(), unregister. |
| */ |
| static void workqueue_sysfs_unregister(struct workqueue_struct *wq) |
| { |
| struct wq_device *wq_dev = wq->wq_dev; |
| |
| if (!wq->wq_dev) |
| return; |
| |
| wq->wq_dev = NULL; |
| device_unregister(&wq_dev->dev); |
| } |
| #else /* CONFIG_SYSFS */ |
| static void workqueue_sysfs_unregister(struct workqueue_struct *wq) { } |
| #endif /* CONFIG_SYSFS */ |
| |
| /* |
| * Workqueue watchdog. |
| * |
| * Stall may be caused by various bugs - missing WQ_MEM_RECLAIM, illegal |
| * flush dependency, a concurrency managed work item which stays RUNNING |
| * indefinitely. Workqueue stalls can be very difficult to debug as the |
| * usual warning mechanisms don't trigger and internal workqueue state is |
| * largely opaque. |
| * |
| * Workqueue watchdog monitors all worker pools periodically and dumps |
| * state if some pools failed to make forward progress for a while where |
| * forward progress is defined as the first item on ->worklist changing. |
| * |
| * This mechanism is controlled through the kernel parameter |
| * "workqueue.watchdog_thresh" which can be updated at runtime through the |
| * corresponding sysfs parameter file. |
| */ |
| #ifdef CONFIG_WQ_WATCHDOG |
| |
| static unsigned long wq_watchdog_thresh = 30; |
| static struct timer_list wq_watchdog_timer; |
| |
| static unsigned long wq_watchdog_touched = INITIAL_JIFFIES; |
| static DEFINE_PER_CPU(unsigned long, wq_watchdog_touched_cpu) = INITIAL_JIFFIES; |
| |
| /* |
| * Show workers that might prevent the processing of pending work items. |
| * The only candidates are CPU-bound workers in the running state. |
| * Pending work items should be handled by another idle worker |
| * in all other situations. |
| */ |
| static void show_cpu_pool_hog(struct worker_pool *pool) |
| { |
| struct worker *worker; |
| unsigned long flags; |
| int bkt; |
| |
| raw_spin_lock_irqsave(&pool->lock, flags); |
| |
| hash_for_each(pool->busy_hash, bkt, worker, hentry) { |
| if (task_is_running(worker->task)) { |
| /* |
| * Defer printing to avoid deadlocks in console |
| * drivers that queue work while holding locks |
| * also taken in their write paths. |
| */ |
| printk_deferred_enter(); |
| |
| pr_info("pool %d:\n", pool->id); |
| sched_show_task(worker->task); |
| |
| printk_deferred_exit(); |
| } |
| } |
| |
| raw_spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| static void show_cpu_pools_hogs(void) |
| { |
| struct worker_pool *pool; |
| int pi; |
| |
| pr_info("Showing backtraces of running workers in stalled CPU-bound worker pools:\n"); |
| |
| rcu_read_lock(); |
| |
| for_each_pool(pool, pi) { |
| if (pool->cpu_stall) |
| show_cpu_pool_hog(pool); |
| |
| } |
| |
| rcu_read_unlock(); |
| } |
| |
| static void wq_watchdog_reset_touched(void) |
| { |
| int cpu; |
| |
| wq_watchdog_touched = jiffies; |
| for_each_possible_cpu(cpu) |
| per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies; |
| } |
| |
| static void wq_watchdog_timer_fn(struct timer_list *unused) |
| { |
| unsigned long thresh = READ_ONCE(wq_watchdog_thresh) * HZ; |
| bool lockup_detected = false; |
| bool cpu_pool_stall = false; |
| unsigned long now = jiffies; |
| struct worker_pool *pool; |
| int pi; |
| |
| if (!thresh) |
| return; |
| |
| rcu_read_lock(); |
| |
| for_each_pool(pool, pi) { |
| unsigned long pool_ts, touched, ts; |
| |
| pool->cpu_stall = false; |
| if (list_empty(&pool->worklist)) |
| continue; |
| |
| /* |
| * If a virtual machine is stopped by the host it can look to |
| * the watchdog like a stall. |
| */ |
| kvm_check_and_clear_guest_paused(); |
| |
| /* get the latest of pool and touched timestamps */ |
| if (pool->cpu >= 0) |
| touched = READ_ONCE(per_cpu(wq_watchdog_touched_cpu, pool->cpu)); |
| else |
| touched = READ_ONCE(wq_watchdog_touched); |
| pool_ts = READ_ONCE(pool->watchdog_ts); |
| |
| if (time_after(pool_ts, touched)) |
| ts = pool_ts; |
| else |
| ts = touched; |
| |
| /* did we stall? */ |
| if (time_after(now, ts + thresh)) { |
| lockup_detected = true; |
| if (pool->cpu >= 0) { |
| pool->cpu_stall = true; |
| cpu_pool_stall = true; |
| } |
| pr_emerg("BUG: workqueue lockup - pool"); |
| pr_cont_pool_info(pool); |
| pr_cont(" stuck for %us!\n", |
| jiffies_to_msecs(now - pool_ts) / 1000); |
| trace_android_vh_wq_lockup_pool(pool->cpu, pool_ts); |
| } |
| |
| |
| } |
| |
| rcu_read_unlock(); |
| |
| if (lockup_detected) |
| show_all_workqueues(); |
| |
| if (cpu_pool_stall) |
| show_cpu_pools_hogs(); |
| |
| wq_watchdog_reset_touched(); |
| mod_timer(&wq_watchdog_timer, jiffies + thresh); |
| } |
| |
| notrace void wq_watchdog_touch(int cpu) |
| { |
| if (cpu >= 0) |
| per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies; |
| |
| wq_watchdog_touched = jiffies; |
| } |
| |
| static void wq_watchdog_set_thresh(unsigned long thresh) |
| { |
| wq_watchdog_thresh = 0; |
| del_timer_sync(&wq_watchdog_timer); |
| |
| if (thresh) { |
| wq_watchdog_thresh = thresh; |
| wq_watchdog_reset_touched(); |
| mod_timer(&wq_watchdog_timer, jiffies + thresh * HZ); |
| } |
| } |
| |
| static int wq_watchdog_param_set_thresh(const char *val, |
| const struct kernel_param *kp) |
| { |
| unsigned long thresh; |
| int ret; |
| |
| ret = kstrtoul(val, 0, &thresh); |
| if (ret) |
| return ret; |
| |
| if (system_wq) |
| wq_watchdog_set_thresh(thresh); |
| else |
| wq_watchdog_thresh = thresh; |
| |
| return 0; |
| } |
| |
| static const struct kernel_param_ops wq_watchdog_thresh_ops = { |
| .set = wq_watchdog_param_set_thresh, |
| .get = param_get_ulong, |
| }; |
| |
| module_param_cb(watchdog_thresh, &wq_watchdog_thresh_ops, &wq_watchdog_thresh, |
| 0644); |
| |
| static void wq_watchdog_init(void) |
| { |
| timer_setup(&wq_watchdog_timer, wq_watchdog_timer_fn, TIMER_DEFERRABLE); |
| wq_watchdog_set_thresh(wq_watchdog_thresh); |
| } |
| |
| #else /* CONFIG_WQ_WATCHDOG */ |
| |
| static inline void wq_watchdog_init(void) { } |
| |
| #endif /* CONFIG_WQ_WATCHDOG */ |
| |
| /** |
| * workqueue_init_early - early init for workqueue subsystem |
| * |
| * This is the first step of three-staged workqueue subsystem initialization and |
| * invoked as soon as the bare basics - memory allocation, cpumasks and idr are |
| * up. It sets up all the data structures and system workqueues and allows early |
| * boot code to create workqueues and queue/cancel work items. Actual work item |
| * execution starts only after kthreads can be created and scheduled right |
| * before early initcalls. |
| */ |
| void __init workqueue_init_early(void) |
| { |
| struct wq_pod_type *pt = &wq_pod_types[WQ_AFFN_SYSTEM]; |
| int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL }; |
| int i, cpu; |
| |
| BUILD_BUG_ON(__alignof__(struct pool_workqueue) < __alignof__(long long)); |
| |
| BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL)); |
| cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_WQ)); |
| cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN)); |
| |
| if (!cpumask_empty(&wq_cmdline_cpumask)) |
| cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, &wq_cmdline_cpumask); |
| |
| pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC); |
| |
| wq_update_pod_attrs_buf = alloc_workqueue_attrs(); |
| BUG_ON(!wq_update_pod_attrs_buf); |
| |
| /* initialize WQ_AFFN_SYSTEM pods */ |
| pt->pod_cpus = kcalloc(1, sizeof(pt->pod_cpus[0]), GFP_KERNEL); |
| pt->pod_node = kcalloc(1, sizeof(pt->pod_node[0]), GFP_KERNEL); |
| pt->cpu_pod = kcalloc(nr_cpu_ids, sizeof(pt->cpu_pod[0]), GFP_KERNEL); |
| BUG_ON(!pt->pod_cpus || !pt->pod_node || !pt->cpu_pod); |
| |
| BUG_ON(!zalloc_cpumask_var_node(&pt->pod_cpus[0], GFP_KERNEL, NUMA_NO_NODE)); |
| |
| pt->nr_pods = 1; |
| cpumask_copy(pt->pod_cpus[0], cpu_possible_mask); |
| pt->pod_node[0] = NUMA_NO_NODE; |
| pt->cpu_pod[0] = 0; |
| |
| /* initialize CPU pools */ |
| for_each_possible_cpu(cpu) { |
| struct worker_pool *pool; |
| |
| i = 0; |
| for_each_cpu_worker_pool(pool, cpu) { |
| BUG_ON(init_worker_pool(pool)); |
| pool->cpu = cpu; |
| cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu)); |
| cpumask_copy(pool->attrs->__pod_cpumask, cpumask_of(cpu)); |
| pool->attrs->nice = std_nice[i++]; |
| pool->attrs->affn_strict = true; |
| pool->node = cpu_to_node(cpu); |
| |
| /* alloc pool ID */ |
| mutex_lock(&wq_pool_mutex); |
| BUG_ON(worker_pool_assign_id(pool)); |
| mutex_unlock(&wq_pool_mutex); |
| } |
| } |
| |
| /* create default unbound and ordered wq attrs */ |
| for (i = 0; i < NR_STD_WORKER_POOLS; i++) { |
| struct workqueue_attrs *attrs; |
| |
| BUG_ON(!(attrs = alloc_workqueue_attrs())); |
| attrs->nice = std_nice[i]; |
| unbound_std_wq_attrs[i] = attrs; |
| |
| /* |
| * An ordered wq should have only one pwq as ordering is |
| * guaranteed by max_active which is enforced by pwqs. |
| */ |
| BUG_ON(!(attrs = alloc_workqueue_attrs())); |
| attrs->nice = std_nice[i]; |
| attrs->ordered = true; |
| ordered_wq_attrs[i] = attrs; |
| } |
| |
| system_wq = alloc_workqueue("events", 0, 0); |
| system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0); |
| system_long_wq = alloc_workqueue("events_long", 0, 0); |
| system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, |
| WQ_MAX_ACTIVE); |
| system_freezable_wq = alloc_workqueue("events_freezable", |
| WQ_FREEZABLE, 0); |
| system_power_efficient_wq = alloc_workqueue("events_power_efficient", |
| WQ_POWER_EFFICIENT, 0); |
| system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient", |
| WQ_FREEZABLE | WQ_POWER_EFFICIENT, |
| 0); |
| BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq || |
| !system_unbound_wq || !system_freezable_wq || |
| !system_power_efficient_wq || |
| !system_freezable_power_efficient_wq); |
| } |
| |
| static void __init wq_cpu_intensive_thresh_init(void) |
| { |
| unsigned long thresh; |
| unsigned long bogo; |
| |
| pwq_release_worker = kthread_create_worker(0, "pool_workqueue_release"); |
| BUG_ON(IS_ERR(pwq_release_worker)); |
| |
| /* if the user set it to a specific value, keep it */ |
| if (wq_cpu_intensive_thresh_us != ULONG_MAX) |
| return; |
| |
| /* |
| * The default of 10ms is derived from the fact that most modern (as of |
| * 2023) processors can do a lot in 10ms and that it's just below what |
| * most consider human-perceivable. However, the kernel also runs on a |
| * lot slower CPUs including microcontrollers where the threshold is way |
| * too low. |
| * |
| * Let's scale up the threshold upto 1 second if BogoMips is below 4000. |
| * This is by no means accurate but it doesn't have to be. The mechanism |
| * is still useful even when the threshold is fully scaled up. Also, as |
| * the reports would usually be applicable to everyone, some machines |
| * operating on longer thresholds won't significantly diminish their |
| * usefulness. |
| */ |
| thresh = 10 * USEC_PER_MSEC; |
| |
| /* see init/calibrate.c for lpj -> BogoMIPS calculation */ |
| bogo = max_t(unsigned long, loops_per_jiffy / 500000 * HZ, 1); |
| if (bogo < 4000) |
| thresh = min_t(unsigned long, thresh * 4000 / bogo, USEC_PER_SEC); |
| |
| pr_debug("wq_cpu_intensive_thresh: lpj=%lu BogoMIPS=%lu thresh_us=%lu\n", |
| loops_per_jiffy, bogo, thresh); |
| |
| wq_cpu_intensive_thresh_us = thresh; |
| } |
| |
| /** |
| * workqueue_init - bring workqueue subsystem fully online |
| * |
| * This is the second step of three-staged workqueue subsystem initialization |
| * and invoked as soon as kthreads can be created and scheduled. Workqueues have |
| * been created and work items queued on them, but there are no kworkers |
| * executing the work items yet. Populate the worker pools with the initial |
| * workers and enable future kworker creations. |
| */ |
| void __init workqueue_init(void) |
| { |
| struct workqueue_struct *wq; |
| struct worker_pool *pool; |
| int cpu, bkt; |
| |
| wq_cpu_intensive_thresh_init(); |
| |
| mutex_lock(&wq_pool_mutex); |
| |
| /* |
| * Per-cpu pools created earlier could be missing node hint. Fix them |
| * up. Also, create a rescuer for workqueues that requested it. |
| */ |
| for_each_possible_cpu(cpu) { |
| for_each_cpu_worker_pool(pool, cpu) { |
| pool->node = cpu_to_node(cpu); |
| } |
| } |
| |
| list_for_each_entry(wq, &workqueues, list) { |
| WARN(init_rescuer(wq), |
| "workqueue: failed to create early rescuer for %s", |
| wq->name); |
| } |
| |
| mutex_unlock(&wq_pool_mutex); |
| |
| /* create the initial workers */ |
| for_each_online_cpu(cpu) { |
| for_each_cpu_worker_pool(pool, cpu) { |
| pool->flags &= ~POOL_DISASSOCIATED; |
| BUG_ON(!create_worker(pool)); |
| } |
| } |
| |
| hash_for_each(unbound_pool_hash, bkt, pool, hash_node) |
| BUG_ON(!create_worker(pool)); |
| |
| wq_online = true; |
| wq_watchdog_init(); |
| } |
| |
| /* |
| * Initialize @pt by first initializing @pt->cpu_pod[] with pod IDs according to |
| * @cpu_shares_pod(). Each subset of CPUs that share a pod is assigned a unique |
| * and consecutive pod ID. The rest of @pt is initialized accordingly. |
| */ |
| static void __init init_pod_type(struct wq_pod_type *pt, |
| bool (*cpus_share_pod)(int, int)) |
| { |
| int cur, pre, cpu, pod; |
| |
| pt->nr_pods = 0; |
| |
| /* init @pt->cpu_pod[] according to @cpus_share_pod() */ |
| pt->cpu_pod = kcalloc(nr_cpu_ids, sizeof(pt->cpu_pod[0]), GFP_KERNEL); |
| BUG_ON(!pt->cpu_pod); |
| |
| for_each_possible_cpu(cur) { |
| for_each_possible_cpu(pre) { |
| if (pre >= cur) { |
| pt->cpu_pod[cur] = pt->nr_pods++; |
| break; |
| } |
| if (cpus_share_pod(cur, pre)) { |
| pt->cpu_pod[cur] = pt->cpu_pod[pre]; |
| break; |
| } |
| } |
| } |
| |
| /* init the rest to match @pt->cpu_pod[] */ |
| pt->pod_cpus = kcalloc(pt->nr_pods, sizeof(pt->pod_cpus[0]), GFP_KERNEL); |
| pt->pod_node = kcalloc(pt->nr_pods, sizeof(pt->pod_node[0]), GFP_KERNEL); |
| BUG_ON(!pt->pod_cpus || !pt->pod_node); |
| |
| for (pod = 0; pod < pt->nr_pods; pod++) |
| BUG_ON(!zalloc_cpumask_var(&pt->pod_cpus[pod], GFP_KERNEL)); |
| |
| for_each_possible_cpu(cpu) { |
| cpumask_set_cpu(cpu, pt->pod_cpus[pt->cpu_pod[cpu]]); |
| pt->pod_node[pt->cpu_pod[cpu]] = cpu_to_node(cpu); |
| } |
| } |
| |
| static bool __init cpus_dont_share(int cpu0, int cpu1) |
| { |
| return false; |
| } |
| |
| static bool __init cpus_share_smt(int cpu0, int cpu1) |
| { |
| #ifdef CONFIG_SCHED_SMT |
| return cpumask_test_cpu(cpu0, cpu_smt_mask(cpu1)); |
| #else |
| return false; |
| #endif |
| } |
| |
| static bool __init cpus_share_numa(int cpu0, int cpu1) |
| { |
| return cpu_to_node(cpu0) == cpu_to_node(cpu1); |
| } |
| |
| /** |
| * workqueue_init_topology - initialize CPU pods for unbound workqueues |
| * |
| * This is the third step of there-staged workqueue subsystem initialization and |
| * invoked after SMP and topology information are fully initialized. It |
| * initializes the unbound CPU pods accordingly. |
| */ |
| void __init workqueue_init_topology(void) |
| { |
| struct workqueue_struct *wq; |
| int cpu; |
| |
| init_pod_type(&wq_pod_types[WQ_AFFN_CPU], cpus_dont_share); |
| init_pod_type(&wq_pod_types[WQ_AFFN_SMT], cpus_share_smt); |
| init_pod_type(&wq_pod_types[WQ_AFFN_CACHE], cpus_share_cache); |
| init_pod_type(&wq_pod_types[WQ_AFFN_NUMA], cpus_share_numa); |
| |
| mutex_lock(&wq_pool_mutex); |
| |
| /* |
| * Workqueues allocated earlier would have all CPUs sharing the default |
| * worker pool. Explicitly call wq_update_pod() on all workqueue and CPU |
| * combinations to apply per-pod sharing. |
| */ |
| list_for_each_entry(wq, &workqueues, list) { |
| for_each_online_cpu(cpu) { |
| wq_update_pod(wq, cpu, cpu, true); |
| } |
| } |
| |
| mutex_unlock(&wq_pool_mutex); |
| } |
| |
| void __warn_flushing_systemwide_wq(void) |
| { |
| pr_warn("WARNING: Flushing system-wide workqueues will be prohibited in near future.\n"); |
| dump_stack(); |
| } |
| EXPORT_SYMBOL(__warn_flushing_systemwide_wq); |
| |
| static int __init workqueue_unbound_cpus_setup(char *str) |
| { |
| if (cpulist_parse(str, &wq_cmdline_cpumask) < 0) { |
| cpumask_clear(&wq_cmdline_cpumask); |
| pr_warn("workqueue.unbound_cpus: incorrect CPU range, using default\n"); |
| } |
| |
| return 1; |
| } |
| __setup("workqueue.unbound_cpus=", workqueue_unbound_cpus_setup); |