Merge tag 'probes-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes updates from Masami Hiramatsu:
"Cleanups:
- kprobes: Fixes typo in kprobes samples
- tracing/eprobes: Remove 'break' after return
kretprobe/fprobe performance improvements:
- lib: Introduce new `objpool`, which is a high performance lockless
object queue. This uses per-cpu ring array to allocate/release
objects from the pre-allocated object pool.
Since the index of ring array is a 32bit sequential counter, we can
retry to push/pop the object pointer from the ring without lock (as
seq-lock does)
- lib: Add an objpool test module to test the functionality and
evaluate the performance under some circumstances
- kprobes/fprobe: Improve kretprobe and rethook scalability
performance with objpool.
This improves both legacy kretprobe and fprobe exit handler (which
is based on rethook) to be scalable on SMP systems. Even with
8-threads parallel test, it shows a great scalability improvement
- Remove unneeded freelist.h which is replaced by objpool
- objpool: Add maintainers entry for the objpool
- objpool: Fix to remove unused include header lines"
* tag 'probes-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
kprobes: unused header files removed
MAINTAINERS: objpool added
kprobes: freelist.h removed
kprobes: kretprobe scalability improvement
lib: objpool test module added
lib: objpool added: ring-array based lockless MPMC
tracing/eprobe: drop unneeded breaks
samples: kprobes: Fixes a typo
diff --git a/MAINTAINERS b/MAINTAINERS
index 6f0dda0..14e1194 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15553,6 +15553,13 @@
F: lib/objagg.c
F: lib/test_objagg.c
+OBJPOOL
+M: Matt Wu <wuqiang.matt@bytedance.com>
+S: Supported
+F: include/linux/objpool.h
+F: lib/objpool.c
+F: lib/test_objpool.c
+
OBJTOOL
M: Josh Poimboeuf <jpoimboe@kernel.org>
M: Peter Zijlstra <peterz@infradead.org>
diff --git a/include/linux/freelist.h b/include/linux/freelist.h
deleted file mode 100644
index fc1842b..0000000
--- a/include/linux/freelist.h
+++ /dev/null
@@ -1,129 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
-#ifndef FREELIST_H
-#define FREELIST_H
-
-#include <linux/atomic.h>
-
-/*
- * Copyright: cameron@moodycamel.com
- *
- * A simple CAS-based lock-free free list. Not the fastest thing in the world
- * under heavy contention, but simple and correct (assuming nodes are never
- * freed until after the free list is destroyed), and fairly speedy under low
- * contention.
- *
- * Adapted from: https://moodycamel.com/blog/2014/solving-the-aba-problem-for-lock-free-free-lists
- */
-
-struct freelist_node {
- atomic_t refs;
- struct freelist_node *next;
-};
-
-struct freelist_head {
- struct freelist_node *head;
-};
-
-#define REFS_ON_FREELIST 0x80000000
-#define REFS_MASK 0x7FFFFFFF
-
-static inline void __freelist_add(struct freelist_node *node, struct freelist_head *list)
-{
- /*
- * Since the refcount is zero, and nobody can increase it once it's
- * zero (except us, and we run only one copy of this method per node at
- * a time, i.e. the single thread case), then we know we can safely
- * change the next pointer of the node; however, once the refcount is
- * back above zero, then other threads could increase it (happens under
- * heavy contention, when the refcount goes to zero in between a load
- * and a refcount increment of a node in try_get, then back up to
- * something non-zero, then the refcount increment is done by the other
- * thread) -- so if the CAS to add the node to the actual list fails,
- * decrese the refcount and leave the add operation to the next thread
- * who puts the refcount back to zero (which could be us, hence the
- * loop).
- */
- struct freelist_node *head = READ_ONCE(list->head);
-
- for (;;) {
- WRITE_ONCE(node->next, head);
- atomic_set_release(&node->refs, 1);
-
- if (!try_cmpxchg_release(&list->head, &head, node)) {
- /*
- * Hmm, the add failed, but we can only try again when
- * the refcount goes back to zero.
- */
- if (atomic_fetch_add_release(REFS_ON_FREELIST - 1, &node->refs) == 1)
- continue;
- }
- return;
- }
-}
-
-static inline void freelist_add(struct freelist_node *node, struct freelist_head *list)
-{
- /*
- * We know that the should-be-on-freelist bit is 0 at this point, so
- * it's safe to set it using a fetch_add.
- */
- if (!atomic_fetch_add_release(REFS_ON_FREELIST, &node->refs)) {
- /*
- * Oh look! We were the last ones referencing this node, and we
- * know we want to add it to the free list, so let's do it!
- */
- __freelist_add(node, list);
- }
-}
-
-static inline struct freelist_node *freelist_try_get(struct freelist_head *list)
-{
- struct freelist_node *prev, *next, *head = smp_load_acquire(&list->head);
- unsigned int refs;
-
- while (head) {
- prev = head;
- refs = atomic_read(&head->refs);
- if ((refs & REFS_MASK) == 0 ||
- !atomic_try_cmpxchg_acquire(&head->refs, &refs, refs+1)) {
- head = smp_load_acquire(&list->head);
- continue;
- }
-
- /*
- * Good, reference count has been incremented (it wasn't at
- * zero), which means we can read the next and not worry about
- * it changing between now and the time we do the CAS.
- */
- next = READ_ONCE(head->next);
- if (try_cmpxchg_acquire(&list->head, &head, next)) {
- /*
- * Yay, got the node. This means it was on the list,
- * which means should-be-on-freelist must be false no
- * matter the refcount (because nobody else knows it's
- * been taken off yet, it can't have been put back on).
- */
- WARN_ON_ONCE(atomic_read(&head->refs) & REFS_ON_FREELIST);
-
- /*
- * Decrease refcount twice, once for our ref, and once
- * for the list's ref.
- */
- atomic_fetch_add(-2, &head->refs);
-
- return head;
- }
-
- /*
- * OK, the head must have changed on us, but we still need to decrement
- * the refcount we increased.
- */
- refs = atomic_fetch_add(-1, &prev->refs);
- if (refs == REFS_ON_FREELIST + 1)
- __freelist_add(prev, list);
- }
-
- return NULL;
-}
-
-#endif /* FREELIST_H */
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 85a64cb..365eb09 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -26,8 +26,7 @@
#include <linux/rcupdate.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>
-#include <linux/refcount.h>
-#include <linux/freelist.h>
+#include <linux/objpool.h>
#include <linux/rethook.h>
#include <asm/kprobes.h>
@@ -141,7 +140,7 @@ static inline bool kprobe_ftrace(struct kprobe *p)
*/
struct kretprobe_holder {
struct kretprobe *rp;
- refcount_t ref;
+ struct objpool_head pool;
};
struct kretprobe {
@@ -154,7 +153,6 @@ struct kretprobe {
#ifdef CONFIG_KRETPROBE_ON_RETHOOK
struct rethook *rh;
#else
- struct freelist_head freelist;
struct kretprobe_holder *rph;
#endif
};
@@ -165,10 +163,7 @@ struct kretprobe_instance {
#ifdef CONFIG_KRETPROBE_ON_RETHOOK
struct rethook_node node;
#else
- union {
- struct freelist_node freelist;
- struct rcu_head rcu;
- };
+ struct rcu_head rcu;
struct llist_node llist;
struct kretprobe_holder *rph;
kprobe_opcode_t *ret_addr;
diff --git a/include/linux/objpool.h b/include/linux/objpool.h
new file mode 100644
index 0000000..15aff4a
--- /dev/null
+++ b/include/linux/objpool.h
@@ -0,0 +1,181 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_OBJPOOL_H
+#define _LINUX_OBJPOOL_H
+
+#include <linux/types.h>
+#include <linux/refcount.h>
+
+/*
+ * objpool: ring-array based lockless MPMC queue
+ *
+ * Copyright: wuqiang.matt@bytedance.com,mhiramat@kernel.org
+ *
+ * objpool is a scalable implementation of high performance queue for
+ * object allocation and reclamation, such as kretprobe instances.
+ *
+ * With leveraging percpu ring-array to mitigate hot spots of memory
+ * contention, it delivers near-linear scalability for high parallel
+ * scenarios. The objpool is best suited for the following cases:
+ * 1) Memory allocation or reclamation are prohibited or too expensive
+ * 2) Consumers are of different priorities, such as irqs and threads
+ *
+ * Limitations:
+ * 1) Maximum objects (capacity) is fixed after objpool creation
+ * 2) All pre-allocated objects are managed in percpu ring array,
+ * which consumes more memory than linked lists
+ */
+
+/**
+ * struct objpool_slot - percpu ring array of objpool
+ * @head: head sequence of the local ring array (to retrieve at)
+ * @tail: tail sequence of the local ring array (to append at)
+ * @last: the last sequence number marked as ready for retrieve
+ * @mask: bits mask for modulo capacity to compute array indexes
+ * @entries: object entries on this slot
+ *
+ * Represents a cpu-local array-based ring buffer, its size is specialized
+ * during initialization of object pool. The percpu objpool node is to be
+ * allocated from local memory for NUMA system, and to be kept compact in
+ * continuous memory: CPU assigned number of objects are stored just after
+ * the body of objpool_node.
+ *
+ * Real size of the ring array is far too smaller than the value range of
+ * head and tail, typed as uint32_t: [0, 2^32), so only lower bits (mask)
+ * of head and tail are used as the actual position in the ring array. In
+ * general the ring array is acting like a small sliding window, which is
+ * always moving forward in the loop of [0, 2^32).
+ */
+struct objpool_slot {
+ uint32_t head;
+ uint32_t tail;
+ uint32_t last;
+ uint32_t mask;
+ void *entries[];
+} __packed;
+
+struct objpool_head;
+
+/*
+ * caller-specified callback for object initial setup, it's only called
+ * once for each object (just after the memory allocation of the object)
+ */
+typedef int (*objpool_init_obj_cb)(void *obj, void *context);
+
+/* caller-specified cleanup callback for objpool destruction */
+typedef int (*objpool_fini_cb)(struct objpool_head *head, void *context);
+
+/**
+ * struct objpool_head - object pooling metadata
+ * @obj_size: object size, aligned to sizeof(void *)
+ * @nr_objs: total objs (to be pre-allocated with objpool)
+ * @nr_cpus: local copy of nr_cpu_ids
+ * @capacity: max objs can be managed by one objpool_slot
+ * @gfp: gfp flags for kmalloc & vmalloc
+ * @ref: refcount of objpool
+ * @flags: flags for objpool management
+ * @cpu_slots: pointer to the array of objpool_slot
+ * @release: resource cleanup callback
+ * @context: caller-provided context
+ */
+struct objpool_head {
+ int obj_size;
+ int nr_objs;
+ int nr_cpus;
+ int capacity;
+ gfp_t gfp;
+ refcount_t ref;
+ unsigned long flags;
+ struct objpool_slot **cpu_slots;
+ objpool_fini_cb release;
+ void *context;
+};
+
+#define OBJPOOL_NR_OBJECT_MAX (1UL << 24) /* maximum numbers of total objects */
+#define OBJPOOL_OBJECT_SIZE_MAX (1UL << 16) /* maximum size of an object */
+
+/**
+ * objpool_init() - initialize objpool and pre-allocated objects
+ * @pool: the object pool to be initialized, declared by caller
+ * @nr_objs: total objects to be pre-allocated by this object pool
+ * @object_size: size of an object (should be > 0)
+ * @gfp: flags for memory allocation (via kmalloc or vmalloc)
+ * @context: user context for object initialization callback
+ * @objinit: object initialization callback for extra setup
+ * @release: cleanup callback for extra cleanup task
+ *
+ * return value: 0 for success, otherwise error code
+ *
+ * All pre-allocated objects are to be zeroed after memory allocation.
+ * Caller could do extra initialization in objinit callback. objinit()
+ * will be called just after slot allocation and called only once for
+ * each object. After that the objpool won't touch any content of the
+ * objects. It's caller's duty to perform reinitialization after each
+ * pop (object allocation) or do clearance before each push (object
+ * reclamation).
+ */
+int objpool_init(struct objpool_head *pool, int nr_objs, int object_size,
+ gfp_t gfp, void *context, objpool_init_obj_cb objinit,
+ objpool_fini_cb release);
+
+/**
+ * objpool_pop() - allocate an object from objpool
+ * @pool: object pool
+ *
+ * return value: object ptr or NULL if failed
+ */
+void *objpool_pop(struct objpool_head *pool);
+
+/**
+ * objpool_push() - reclaim the object and return back to objpool
+ * @obj: object ptr to be pushed to objpool
+ * @pool: object pool
+ *
+ * return: 0 or error code (it fails only when user tries to push
+ * the same object multiple times or wrong "objects" into objpool)
+ */
+int objpool_push(void *obj, struct objpool_head *pool);
+
+/**
+ * objpool_drop() - discard the object and deref objpool
+ * @obj: object ptr to be discarded
+ * @pool: object pool
+ *
+ * return: 0 if objpool was released; -EAGAIN if there are still
+ * outstanding objects
+ *
+ * objpool_drop is normally for the release of outstanding objects
+ * after objpool cleanup (objpool_fini). Thinking of this example:
+ * kretprobe is unregistered and objpool_fini() is called to release
+ * all remained objects, but there are still objects being used by
+ * unfinished kretprobes (like blockable function: sys_accept). So
+ * only when the last outstanding object is dropped could the whole
+ * objpool be released along with the call of objpool_drop()
+ */
+int objpool_drop(void *obj, struct objpool_head *pool);
+
+/**
+ * objpool_free() - release objpool forcely (all objects to be freed)
+ * @pool: object pool to be released
+ */
+void objpool_free(struct objpool_head *pool);
+
+/**
+ * objpool_fini() - deref object pool (also releasing unused objects)
+ * @pool: object pool to be dereferenced
+ *
+ * objpool_fini() will try to release all remained free objects and
+ * then drop an extra reference of the objpool. If all objects are
+ * already returned to objpool (so called synchronous use cases),
+ * the objpool itself will be freed together. But if there are still
+ * outstanding objects (so called asynchronous use cases, such like
+ * blockable kretprobe), the objpool won't be released until all
+ * the outstanding objects are dropped, but the caller must assure
+ * there are no concurrent objpool_push() on the fly. Normally RCU
+ * is being required to make sure all ongoing objpool_push() must
+ * be finished before calling objpool_fini(), so does test_objpool,
+ * kretprobe or rethook
+ */
+void objpool_fini(struct objpool_head *pool);
+
+#endif /* _LINUX_OBJPOOL_H */
diff --git a/include/linux/rethook.h b/include/linux/rethook.h
index 26b6f3c..ce69b2b 100644
--- a/include/linux/rethook.h
+++ b/include/linux/rethook.h
@@ -6,11 +6,10 @@
#define _LINUX_RETHOOK_H
#include <linux/compiler.h>
-#include <linux/freelist.h>
+#include <linux/objpool.h>
#include <linux/kallsyms.h>
#include <linux/llist.h>
#include <linux/rcupdate.h>
-#include <linux/refcount.h>
struct rethook_node;
@@ -30,14 +29,12 @@ typedef void (*rethook_handler_t) (struct rethook_node *, void *, unsigned long,
struct rethook {
void *data;
rethook_handler_t handler;
- struct freelist_head pool;
- refcount_t ref;
+ struct objpool_head pool;
struct rcu_head rcu;
};
/**
* struct rethook_node - The rethook shadow-stack entry node.
- * @freelist: The freelist, linked to struct rethook::pool.
* @rcu: The rcu_head for deferred freeing.
* @llist: The llist, linked to a struct task_struct::rethooks.
* @rethook: The pointer to the struct rethook.
@@ -48,20 +45,16 @@ struct rethook {
* on each entry of the shadow stack.
*/
struct rethook_node {
- union {
- struct freelist_node freelist;
- struct rcu_head rcu;
- };
+ struct rcu_head rcu;
struct llist_node llist;
struct rethook *rethook;
unsigned long ret_addr;
unsigned long frame;
};
-struct rethook *rethook_alloc(void *data, rethook_handler_t handler);
+struct rethook *rethook_alloc(void *data, rethook_handler_t handler, int size, int num);
void rethook_stop(struct rethook *rh);
void rethook_free(struct rethook *rh);
-void rethook_add_node(struct rethook *rh, struct rethook_node *node);
struct rethook_node *rethook_try_get(struct rethook *rh);
void rethook_recycle(struct rethook_node *node);
void rethook_hook(struct rethook_node *node, struct pt_regs *regs, bool mcount);
@@ -98,4 +91,3 @@ void rethook_flush_task(struct task_struct *tk);
#endif
#endif
-
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 0c6185a..075a632 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1877,13 +1877,27 @@ static struct notifier_block kprobe_exceptions_nb = {
#ifdef CONFIG_KRETPROBES
#if !defined(CONFIG_KRETPROBE_ON_RETHOOK)
+
+/* callbacks for objpool of kretprobe instances */
+static int kretprobe_init_inst(void *nod, void *context)
+{
+ struct kretprobe_instance *ri = nod;
+
+ ri->rph = context;
+ return 0;
+}
+static int kretprobe_fini_pool(struct objpool_head *head, void *context)
+{
+ kfree(context);
+ return 0;
+}
+
static void free_rp_inst_rcu(struct rcu_head *head)
{
struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu);
+ struct kretprobe_holder *rph = ri->rph;
- if (refcount_dec_and_test(&ri->rph->ref))
- kfree(ri->rph);
- kfree(ri);
+ objpool_drop(ri, &rph->pool);
}
NOKPROBE_SYMBOL(free_rp_inst_rcu);
@@ -1892,7 +1906,7 @@ static void recycle_rp_inst(struct kretprobe_instance *ri)
struct kretprobe *rp = get_kretprobe(ri);
if (likely(rp))
- freelist_add(&ri->freelist, &rp->freelist);
+ objpool_push(ri, &rp->rph->pool);
else
call_rcu(&ri->rcu, free_rp_inst_rcu);
}
@@ -1929,23 +1943,12 @@ NOKPROBE_SYMBOL(kprobe_flush_task);
static inline void free_rp_inst(struct kretprobe *rp)
{
- struct kretprobe_instance *ri;
- struct freelist_node *node;
- int count = 0;
+ struct kretprobe_holder *rph = rp->rph;
- node = rp->freelist.head;
- while (node) {
- ri = container_of(node, struct kretprobe_instance, freelist);
- node = node->next;
-
- kfree(ri);
- count++;
- }
-
- if (refcount_sub_and_test(count, &rp->rph->ref)) {
- kfree(rp->rph);
- rp->rph = NULL;
- }
+ if (!rph)
+ return;
+ rp->rph = NULL;
+ objpool_fini(&rph->pool);
}
/* This assumes the 'tsk' is the current task or the is not running. */
@@ -2087,19 +2090,17 @@ NOKPROBE_SYMBOL(__kretprobe_trampoline_handler)
static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe *rp = container_of(p, struct kretprobe, kp);
+ struct kretprobe_holder *rph = rp->rph;
struct kretprobe_instance *ri;
- struct freelist_node *fn;
- fn = freelist_try_get(&rp->freelist);
- if (!fn) {
+ ri = objpool_pop(&rph->pool);
+ if (!ri) {
rp->nmissed++;
return 0;
}
- ri = container_of(fn, struct kretprobe_instance, freelist);
-
if (rp->entry_handler && rp->entry_handler(ri, regs)) {
- freelist_add(&ri->freelist, &rp->freelist);
+ objpool_push(ri, &rph->pool);
return 0;
}
@@ -2193,7 +2194,6 @@ int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long o
int register_kretprobe(struct kretprobe *rp)
{
int ret;
- struct kretprobe_instance *inst;
int i;
void *addr;
@@ -2227,19 +2227,12 @@ int register_kretprobe(struct kretprobe *rp)
rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
#ifdef CONFIG_KRETPROBE_ON_RETHOOK
- rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler);
- if (!rp->rh)
- return -ENOMEM;
+ rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler,
+ sizeof(struct kretprobe_instance) +
+ rp->data_size, rp->maxactive);
+ if (IS_ERR(rp->rh))
+ return PTR_ERR(rp->rh);
- for (i = 0; i < rp->maxactive; i++) {
- inst = kzalloc(struct_size(inst, data, rp->data_size), GFP_KERNEL);
- if (inst == NULL) {
- rethook_free(rp->rh);
- rp->rh = NULL;
- return -ENOMEM;
- }
- rethook_add_node(rp->rh, &inst->node);
- }
rp->nmissed = 0;
/* Establish function entry probe point */
ret = register_kprobe(&rp->kp);
@@ -2248,24 +2241,18 @@ int register_kretprobe(struct kretprobe *rp)
rp->rh = NULL;
}
#else /* !CONFIG_KRETPROBE_ON_RETHOOK */
- rp->freelist.head = NULL;
rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL);
if (!rp->rph)
return -ENOMEM;
- rp->rph->rp = rp;
- for (i = 0; i < rp->maxactive; i++) {
- inst = kzalloc(struct_size(inst, data, rp->data_size), GFP_KERNEL);
- if (inst == NULL) {
- refcount_set(&rp->rph->ref, i);
- free_rp_inst(rp);
- return -ENOMEM;
- }
- inst->rph = rp->rph;
- freelist_add(&inst->freelist, &rp->freelist);
+ if (objpool_init(&rp->rph->pool, rp->maxactive, rp->data_size +
+ sizeof(struct kretprobe_instance), GFP_KERNEL,
+ rp->rph, kretprobe_init_inst, kretprobe_fini_pool)) {
+ kfree(rp->rph);
+ rp->rph = NULL;
+ return -ENOMEM;
}
- refcount_set(&rp->rph->ref, i);
-
+ rp->rph->rp = rp;
rp->nmissed = 0;
/* Establish function entry probe point */
ret = register_kprobe(&rp->kp);
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 881f90f..6cd2a4e 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -187,7 +187,7 @@ static void fprobe_init(struct fprobe *fp)
static int fprobe_init_rethook(struct fprobe *fp, int num)
{
- int i, size;
+ int size;
if (num <= 0)
return -EINVAL;
@@ -205,26 +205,18 @@ static int fprobe_init_rethook(struct fprobe *fp, int num)
if (size <= 0)
return -EINVAL;
- fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler);
- if (!fp->rethook)
- return -ENOMEM;
- for (i = 0; i < size; i++) {
- struct fprobe_rethook_node *node;
+ /* Initialize rethook */
+ fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler,
+ sizeof(struct fprobe_rethook_node), size);
+ if (IS_ERR(fp->rethook))
+ return PTR_ERR(fp->rethook);
- node = kzalloc(sizeof(*node) + fp->entry_data_size, GFP_KERNEL);
- if (!node) {
- rethook_free(fp->rethook);
- fp->rethook = NULL;
- return -ENOMEM;
- }
- rethook_add_node(fp->rethook, &node->node);
- }
return 0;
}
static void fprobe_fail_cleanup(struct fprobe *fp)
{
- if (fp->rethook) {
+ if (!IS_ERR_OR_NULL(fp->rethook)) {
/* Don't need to cleanup rethook->handler because this is not used. */
rethook_free(fp->rethook);
fp->rethook = NULL;
@@ -379,14 +371,14 @@ int unregister_fprobe(struct fprobe *fp)
if (!fprobe_is_registered(fp))
return -EINVAL;
- if (fp->rethook)
+ if (!IS_ERR_OR_NULL(fp->rethook))
rethook_stop(fp->rethook);
ret = unregister_ftrace_function(&fp->ops);
if (ret < 0)
return ret;
- if (fp->rethook)
+ if (!IS_ERR_OR_NULL(fp->rethook))
rethook_free(fp->rethook);
ftrace_free_filter(&fp->ops);
diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c
index 5eb9b59..6fd7d4e 100644
--- a/kernel/trace/rethook.c
+++ b/kernel/trace/rethook.c
@@ -8,7 +8,6 @@
#include <linux/preempt.h>
#include <linux/rethook.h>
#include <linux/slab.h>
-#include <linux/sort.h>
/* Return hook list (shadow stack by list) */
@@ -36,21 +35,7 @@ void rethook_flush_task(struct task_struct *tk)
static void rethook_free_rcu(struct rcu_head *head)
{
struct rethook *rh = container_of(head, struct rethook, rcu);
- struct rethook_node *rhn;
- struct freelist_node *node;
- int count = 1;
-
- node = rh->pool.head;
- while (node) {
- rhn = container_of(node, struct rethook_node, freelist);
- node = node->next;
- kfree(rhn);
- count++;
- }
-
- /* The rh->ref is the number of pooled node + 1 */
- if (refcount_sub_and_test(count, &rh->ref))
- kfree(rh);
+ objpool_fini(&rh->pool);
}
/**
@@ -83,54 +68,62 @@ void rethook_free(struct rethook *rh)
call_rcu(&rh->rcu, rethook_free_rcu);
}
-/**
- * rethook_alloc() - Allocate struct rethook.
- * @data: a data to pass the @handler when hooking the return.
- * @handler: the return hook callback function.
- *
- * Allocate and initialize a new rethook with @data and @handler.
- * Return NULL if memory allocation fails or @handler is NULL.
- * Note that @handler == NULL means this rethook is going to be freed.
- */
-struct rethook *rethook_alloc(void *data, rethook_handler_t handler)
+static int rethook_init_node(void *nod, void *context)
{
- struct rethook *rh = kzalloc(sizeof(struct rethook), GFP_KERNEL);
+ struct rethook_node *node = nod;
- if (!rh || !handler) {
- kfree(rh);
- return NULL;
- }
+ node->rethook = context;
+ return 0;
+}
- rh->data = data;
- rh->handler = handler;
- rh->pool.head = NULL;
- refcount_set(&rh->ref, 1);
-
- return rh;
+static int rethook_fini_pool(struct objpool_head *head, void *context)
+{
+ kfree(context);
+ return 0;
}
/**
- * rethook_add_node() - Add a new node to the rethook.
- * @rh: the struct rethook.
- * @node: the struct rethook_node to be added.
+ * rethook_alloc() - Allocate struct rethook.
+ * @data: a data to pass the @handler when hooking the return.
+ * @handler: the return hook callback function, must NOT be NULL
+ * @size: node size: rethook node and additional data
+ * @num: number of rethook nodes to be preallocated
*
- * Add @node to @rh. User must allocate @node (as a part of user's
- * data structure.) The @node fields are initialized in this function.
+ * Allocate and initialize a new rethook with @data and @handler.
+ * Return pointer of new rethook, or error codes for failures.
+ *
+ * Note that @handler == NULL means this rethook is going to be freed.
*/
-void rethook_add_node(struct rethook *rh, struct rethook_node *node)
+struct rethook *rethook_alloc(void *data, rethook_handler_t handler,
+ int size, int num)
{
- node->rethook = rh;
- freelist_add(&node->freelist, &rh->pool);
- refcount_inc(&rh->ref);
+ struct rethook *rh;
+
+ if (!handler || num <= 0 || size < sizeof(struct rethook_node))
+ return ERR_PTR(-EINVAL);
+
+ rh = kzalloc(sizeof(struct rethook), GFP_KERNEL);
+ if (!rh)
+ return ERR_PTR(-ENOMEM);
+
+ rh->data = data;
+ rh->handler = handler;
+
+ /* initialize the objpool for rethook nodes */
+ if (objpool_init(&rh->pool, num, size, GFP_KERNEL, rh,
+ rethook_init_node, rethook_fini_pool)) {
+ kfree(rh);
+ return ERR_PTR(-ENOMEM);
+ }
+ return rh;
}
static void free_rethook_node_rcu(struct rcu_head *head)
{
struct rethook_node *node = container_of(head, struct rethook_node, rcu);
+ struct rethook *rh = node->rethook;
- if (refcount_dec_and_test(&node->rethook->ref))
- kfree(node->rethook);
- kfree(node);
+ objpool_drop(node, &rh->pool);
}
/**
@@ -145,7 +138,7 @@ void rethook_recycle(struct rethook_node *node)
lockdep_assert_preemption_disabled();
if (likely(READ_ONCE(node->rethook->handler)))
- freelist_add(&node->freelist, &node->rethook->pool);
+ objpool_push(node, &node->rethook->pool);
else
call_rcu(&node->rcu, free_rethook_node_rcu);
}
@@ -161,7 +154,6 @@ NOKPROBE_SYMBOL(rethook_recycle);
struct rethook_node *rethook_try_get(struct rethook *rh)
{
rethook_handler_t handler = READ_ONCE(rh->handler);
- struct freelist_node *fn;
lockdep_assert_preemption_disabled();
@@ -178,11 +170,7 @@ struct rethook_node *rethook_try_get(struct rethook *rh)
if (unlikely(!rcu_is_watching()))
return NULL;
- fn = freelist_try_get(&rh->pool);
- if (!fn)
- return NULL;
-
- return container_of(fn, struct rethook_node, freelist);
+ return (struct rethook_node *)objpool_pop(&rh->pool);
}
NOKPROBE_SYMBOL(rethook_try_get);
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 72714cb..03c851f 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -788,12 +788,9 @@ find_and_get_event(const char *system, const char *event_name)
name = trace_event_name(tp_event);
if (!name || strcmp(event_name, name))
continue;
- if (!trace_event_try_get_ref(tp_event)) {
+ if (!trace_event_try_get_ref(tp_event))
return NULL;
- break;
- }
return tp_event;
- break;
}
return NULL;
}
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 40b77c4..cc7d53d 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2954,6 +2954,17 @@
If unsure, say N.
+config TEST_OBJPOOL
+ tristate "Test module for correctness and stress of objpool"
+ default n
+ depends on m && DEBUG_KERNEL
+ help
+ This builds the "test_objpool" module that should be used for
+ correctness verification and concurrent testings of objects
+ allocation and reclamation.
+
+ If unsure, say N.
+
endif # RUNTIME_TESTING_MENU
config ARCH_USE_MEMTEST
diff --git a/lib/Makefile b/lib/Makefile
index 1b311c7..9e0972f 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -34,7 +34,7 @@
is_single_threaded.o plist.o decompress.o kobject_uevent.o \
earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
nmi_backtrace.o win_minmax.o memcat_p.o \
- buildid.o
+ buildid.o objpool.o
lib-$(CONFIG_PRINTK) += dump_stack.o
lib-$(CONFIG_SMP) += cpumask.o
@@ -107,6 +107,8 @@
obj-$(CONFIG_TEST_REF_TRACKER) += test_ref_tracker.o
CFLAGS_test_fprobe.o += $(CC_FLAGS_FTRACE)
obj-$(CONFIG_FPROBE_SANITY_TEST) += test_fprobe.o
+obj-$(CONFIG_TEST_OBJPOOL) += test_objpool.o
+
#
# CFLAGS for compiling floating point code inside the kernel. x86/Makefile turns
# off the generation of FPU/SSE* instructions for kernel proper but FPU_FLAGS
diff --git a/lib/objpool.c b/lib/objpool.c
new file mode 100644
index 0000000..ce0087f
--- /dev/null
+++ b/lib/objpool.c
@@ -0,0 +1,280 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/objpool.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/atomic.h>
+#include <linux/irqflags.h>
+#include <linux/cpumask.h>
+#include <linux/log2.h>
+
+/*
+ * objpool: ring-array based lockless MPMC/FIFO queues
+ *
+ * Copyright: wuqiang.matt@bytedance.com,mhiramat@kernel.org
+ */
+
+/* initialize percpu objpool_slot */
+static int
+objpool_init_percpu_slot(struct objpool_head *pool,
+ struct objpool_slot *slot,
+ int nodes, void *context,
+ objpool_init_obj_cb objinit)
+{
+ void *obj = (void *)&slot->entries[pool->capacity];
+ int i;
+
+ /* initialize elements of percpu objpool_slot */
+ slot->mask = pool->capacity - 1;
+
+ for (i = 0; i < nodes; i++) {
+ if (objinit) {
+ int rc = objinit(obj, context);
+ if (rc)
+ return rc;
+ }
+ slot->entries[slot->tail & slot->mask] = obj;
+ obj = obj + pool->obj_size;
+ slot->tail++;
+ slot->last = slot->tail;
+ pool->nr_objs++;
+ }
+
+ return 0;
+}
+
+/* allocate and initialize percpu slots */
+static int
+objpool_init_percpu_slots(struct objpool_head *pool, int nr_objs,
+ void *context, objpool_init_obj_cb objinit)
+{
+ int i, cpu_count = 0;
+
+ for (i = 0; i < pool->nr_cpus; i++) {
+
+ struct objpool_slot *slot;
+ int nodes, size, rc;
+
+ /* skip the cpu node which could never be present */
+ if (!cpu_possible(i))
+ continue;
+
+ /* compute how many objects to be allocated with this slot */
+ nodes = nr_objs / num_possible_cpus();
+ if (cpu_count < (nr_objs % num_possible_cpus()))
+ nodes++;
+ cpu_count++;
+
+ size = struct_size(slot, entries, pool->capacity) +
+ pool->obj_size * nodes;
+
+ /*
+ * here we allocate percpu-slot & objs together in a single
+ * allocation to make it more compact, taking advantage of
+ * warm caches and TLB hits. in default vmalloc is used to
+ * reduce the pressure of kernel slab system. as we know,
+ * mimimal size of vmalloc is one page since vmalloc would
+ * always align the requested size to page size
+ */
+ if (pool->gfp & GFP_ATOMIC)
+ slot = kmalloc_node(size, pool->gfp, cpu_to_node(i));
+ else
+ slot = __vmalloc_node(size, sizeof(void *), pool->gfp,
+ cpu_to_node(i), __builtin_return_address(0));
+ if (!slot)
+ return -ENOMEM;
+ memset(slot, 0, size);
+ pool->cpu_slots[i] = slot;
+
+ /* initialize the objpool_slot of cpu node i */
+ rc = objpool_init_percpu_slot(pool, slot, nodes, context, objinit);
+ if (rc)
+ return rc;
+ }
+
+ return 0;
+}
+
+/* cleanup all percpu slots of the object pool */
+static void objpool_fini_percpu_slots(struct objpool_head *pool)
+{
+ int i;
+
+ if (!pool->cpu_slots)
+ return;
+
+ for (i = 0; i < pool->nr_cpus; i++)
+ kvfree(pool->cpu_slots[i]);
+ kfree(pool->cpu_slots);
+}
+
+/* initialize object pool and pre-allocate objects */
+int objpool_init(struct objpool_head *pool, int nr_objs, int object_size,
+ gfp_t gfp, void *context, objpool_init_obj_cb objinit,
+ objpool_fini_cb release)
+{
+ int rc, capacity, slot_size;
+
+ /* check input parameters */
+ if (nr_objs <= 0 || nr_objs > OBJPOOL_NR_OBJECT_MAX ||
+ object_size <= 0 || object_size > OBJPOOL_OBJECT_SIZE_MAX)
+ return -EINVAL;
+
+ /* align up to unsigned long size */
+ object_size = ALIGN(object_size, sizeof(long));
+
+ /* calculate capacity of percpu objpool_slot */
+ capacity = roundup_pow_of_two(nr_objs);
+ if (!capacity)
+ return -EINVAL;
+
+ /* initialize objpool pool */
+ memset(pool, 0, sizeof(struct objpool_head));
+ pool->nr_cpus = nr_cpu_ids;
+ pool->obj_size = object_size;
+ pool->capacity = capacity;
+ pool->gfp = gfp & ~__GFP_ZERO;
+ pool->context = context;
+ pool->release = release;
+ slot_size = pool->nr_cpus * sizeof(struct objpool_slot);
+ pool->cpu_slots = kzalloc(slot_size, pool->gfp);
+ if (!pool->cpu_slots)
+ return -ENOMEM;
+
+ /* initialize per-cpu slots */
+ rc = objpool_init_percpu_slots(pool, nr_objs, context, objinit);
+ if (rc)
+ objpool_fini_percpu_slots(pool);
+ else
+ refcount_set(&pool->ref, pool->nr_objs + 1);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(objpool_init);
+
+/* adding object to slot, abort if the slot was already full */
+static inline int
+objpool_try_add_slot(void *obj, struct objpool_head *pool, int cpu)
+{
+ struct objpool_slot *slot = pool->cpu_slots[cpu];
+ uint32_t head, tail;
+
+ /* loading tail and head as a local snapshot, tail first */
+ tail = READ_ONCE(slot->tail);
+
+ do {
+ head = READ_ONCE(slot->head);
+ /* fault caught: something must be wrong */
+ WARN_ON_ONCE(tail - head > pool->nr_objs);
+ } while (!try_cmpxchg_acquire(&slot->tail, &tail, tail + 1));
+
+ /* now the tail position is reserved for the given obj */
+ WRITE_ONCE(slot->entries[tail & slot->mask], obj);
+ /* update sequence to make this obj available for pop() */
+ smp_store_release(&slot->last, tail + 1);
+
+ return 0;
+}
+
+/* reclaim an object to object pool */
+int objpool_push(void *obj, struct objpool_head *pool)
+{
+ unsigned long flags;
+ int rc;
+
+ /* disable local irq to avoid preemption & interruption */
+ raw_local_irq_save(flags);
+ rc = objpool_try_add_slot(obj, pool, raw_smp_processor_id());
+ raw_local_irq_restore(flags);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(objpool_push);
+
+/* try to retrieve object from slot */
+static inline void *objpool_try_get_slot(struct objpool_head *pool, int cpu)
+{
+ struct objpool_slot *slot = pool->cpu_slots[cpu];
+ /* load head snapshot, other cpus may change it */
+ uint32_t head = smp_load_acquire(&slot->head);
+
+ while (head != READ_ONCE(slot->last)) {
+ void *obj;
+
+ /* obj must be retrieved before moving forward head */
+ obj = READ_ONCE(slot->entries[head & slot->mask]);
+
+ /* move head forward to mark it's consumption */
+ if (try_cmpxchg_release(&slot->head, &head, head + 1))
+ return obj;
+ }
+
+ return NULL;
+}
+
+/* allocate an object from object pool */
+void *objpool_pop(struct objpool_head *pool)
+{
+ void *obj = NULL;
+ unsigned long flags;
+ int i, cpu;
+
+ /* disable local irq to avoid preemption & interruption */
+ raw_local_irq_save(flags);
+
+ cpu = raw_smp_processor_id();
+ for (i = 0; i < num_possible_cpus(); i++) {
+ obj = objpool_try_get_slot(pool, cpu);
+ if (obj)
+ break;
+ cpu = cpumask_next_wrap(cpu, cpu_possible_mask, -1, 1);
+ }
+ raw_local_irq_restore(flags);
+
+ return obj;
+}
+EXPORT_SYMBOL_GPL(objpool_pop);
+
+/* release whole objpool forcely */
+void objpool_free(struct objpool_head *pool)
+{
+ if (!pool->cpu_slots)
+ return;
+
+ /* release percpu slots */
+ objpool_fini_percpu_slots(pool);
+
+ /* call user's cleanup callback if provided */
+ if (pool->release)
+ pool->release(pool, pool->context);
+}
+EXPORT_SYMBOL_GPL(objpool_free);
+
+/* drop the allocated object, rather reclaim it to objpool */
+int objpool_drop(void *obj, struct objpool_head *pool)
+{
+ if (!obj || !pool)
+ return -EINVAL;
+
+ if (refcount_dec_and_test(&pool->ref)) {
+ objpool_free(pool);
+ return 0;
+ }
+
+ return -EAGAIN;
+}
+EXPORT_SYMBOL_GPL(objpool_drop);
+
+/* drop unused objects and defref objpool for releasing */
+void objpool_fini(struct objpool_head *pool)
+{
+ int count = 1; /* extra ref for objpool itself */
+
+ /* drop all remained objects from objpool */
+ while (objpool_pop(pool))
+ count++;
+
+ if (refcount_sub_and_test(count, &pool->ref))
+ objpool_free(pool);
+}
+EXPORT_SYMBOL_GPL(objpool_fini);
diff --git a/lib/test_objpool.c b/lib/test_objpool.c
new file mode 100644
index 0000000..a9407840
--- /dev/null
+++ b/lib/test_objpool.c
@@ -0,0 +1,690 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Test module for lockless object pool
+ *
+ * Copyright: wuqiang.matt@bytedance.com
+ */
+
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/completion.h>
+#include <linux/kthread.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/delay.h>
+#include <linux/hrtimer.h>
+#include <linux/objpool.h>
+
+#define OT_NR_MAX_BULK (16)
+
+/* memory usage */
+struct ot_mem_stat {
+ atomic_long_t alloc;
+ atomic_long_t free;
+};
+
+/* object allocation results */
+struct ot_obj_stat {
+ unsigned long nhits;
+ unsigned long nmiss;
+};
+
+/* control & results per testcase */
+struct ot_data {
+ struct rw_semaphore start;
+ struct completion wait;
+ struct completion rcu;
+ atomic_t nthreads ____cacheline_aligned_in_smp;
+ atomic_t stop ____cacheline_aligned_in_smp;
+ struct ot_mem_stat kmalloc;
+ struct ot_mem_stat vmalloc;
+ struct ot_obj_stat objects;
+ u64 duration;
+};
+
+/* testcase */
+struct ot_test {
+ int async; /* synchronous or asynchronous */
+ int mode; /* only mode 0 supported */
+ int objsz; /* object size */
+ int duration; /* ms */
+ int delay; /* ms */
+ int bulk_normal;
+ int bulk_irq;
+ unsigned long hrtimer; /* ms */
+ const char *name;
+ struct ot_data data;
+};
+
+/* per-cpu worker */
+struct ot_item {
+ struct objpool_head *pool; /* pool head */
+ struct ot_test *test; /* test parameters */
+
+ void (*worker)(struct ot_item *item, int irq);
+
+ /* hrtimer control */
+ ktime_t hrtcycle;
+ struct hrtimer hrtimer;
+
+ int bulk[2]; /* for thread and irq */
+ int delay;
+ u32 niters;
+
+ /* summary per thread */
+ struct ot_obj_stat stat[2]; /* thread and irq */
+ u64 duration;
+};
+
+/*
+ * memory leakage checking
+ */
+
+static void *ot_kzalloc(struct ot_test *test, long size)
+{
+ void *ptr = kzalloc(size, GFP_KERNEL);
+
+ if (ptr)
+ atomic_long_add(size, &test->data.kmalloc.alloc);
+ return ptr;
+}
+
+static void ot_kfree(struct ot_test *test, void *ptr, long size)
+{
+ if (!ptr)
+ return;
+ atomic_long_add(size, &test->data.kmalloc.free);
+ kfree(ptr);
+}
+
+static void ot_mem_report(struct ot_test *test)
+{
+ long alloc, free;
+
+ pr_info("memory allocation summary for %s\n", test->name);
+
+ alloc = atomic_long_read(&test->data.kmalloc.alloc);
+ free = atomic_long_read(&test->data.kmalloc.free);
+ pr_info(" kmalloc: %lu - %lu = %lu\n", alloc, free, alloc - free);
+
+ alloc = atomic_long_read(&test->data.vmalloc.alloc);
+ free = atomic_long_read(&test->data.vmalloc.free);
+ pr_info(" vmalloc: %lu - %lu = %lu\n", alloc, free, alloc - free);
+}
+
+/* user object instance */
+struct ot_node {
+ void *owner;
+ unsigned long data;
+ unsigned long refs;
+ unsigned long payload[32];
+};
+
+/* user objpool manager */
+struct ot_context {
+ struct objpool_head pool; /* objpool head */
+ struct ot_test *test; /* test parameters */
+ void *ptr; /* user pool buffer */
+ unsigned long size; /* buffer size */
+ struct rcu_head rcu;
+};
+
+static DEFINE_PER_CPU(struct ot_item, ot_pcup_items);
+
+static int ot_init_data(struct ot_data *data)
+{
+ memset(data, 0, sizeof(*data));
+ init_rwsem(&data->start);
+ init_completion(&data->wait);
+ init_completion(&data->rcu);
+ atomic_set(&data->nthreads, 1);
+
+ return 0;
+}
+
+static int ot_init_node(void *nod, void *context)
+{
+ struct ot_context *sop = context;
+ struct ot_node *on = nod;
+
+ on->owner = &sop->pool;
+ return 0;
+}
+
+static enum hrtimer_restart ot_hrtimer_handler(struct hrtimer *hrt)
+{
+ struct ot_item *item = container_of(hrt, struct ot_item, hrtimer);
+ struct ot_test *test = item->test;
+
+ if (atomic_read_acquire(&test->data.stop))
+ return HRTIMER_NORESTART;
+
+ /* do bulk-testings for objects pop/push */
+ item->worker(item, 1);
+
+ hrtimer_forward(hrt, hrt->base->get_time(), item->hrtcycle);
+ return HRTIMER_RESTART;
+}
+
+static void ot_start_hrtimer(struct ot_item *item)
+{
+ if (!item->test->hrtimer)
+ return;
+ hrtimer_start(&item->hrtimer, item->hrtcycle, HRTIMER_MODE_REL);
+}
+
+static void ot_stop_hrtimer(struct ot_item *item)
+{
+ if (!item->test->hrtimer)
+ return;
+ hrtimer_cancel(&item->hrtimer);
+}
+
+static int ot_init_hrtimer(struct ot_item *item, unsigned long hrtimer)
+{
+ struct hrtimer *hrt = &item->hrtimer;
+
+ if (!hrtimer)
+ return -ENOENT;
+
+ item->hrtcycle = ktime_set(0, hrtimer * 1000000UL);
+ hrtimer_init(hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hrt->function = ot_hrtimer_handler;
+ return 0;
+}
+
+static int ot_init_cpu_item(struct ot_item *item,
+ struct ot_test *test,
+ struct objpool_head *pool,
+ void (*worker)(struct ot_item *, int))
+{
+ memset(item, 0, sizeof(*item));
+ item->pool = pool;
+ item->test = test;
+ item->worker = worker;
+
+ item->bulk[0] = test->bulk_normal;
+ item->bulk[1] = test->bulk_irq;
+ item->delay = test->delay;
+
+ /* initialize hrtimer */
+ ot_init_hrtimer(item, item->test->hrtimer);
+ return 0;
+}
+
+static int ot_thread_worker(void *arg)
+{
+ struct ot_item *item = arg;
+ struct ot_test *test = item->test;
+ ktime_t start;
+
+ atomic_inc(&test->data.nthreads);
+ down_read(&test->data.start);
+ up_read(&test->data.start);
+ start = ktime_get();
+ ot_start_hrtimer(item);
+ do {
+ if (atomic_read_acquire(&test->data.stop))
+ break;
+ /* do bulk-testings for objects pop/push */
+ item->worker(item, 0);
+ } while (!kthread_should_stop());
+ ot_stop_hrtimer(item);
+ item->duration = (u64) ktime_us_delta(ktime_get(), start);
+ if (atomic_dec_and_test(&test->data.nthreads))
+ complete(&test->data.wait);
+
+ return 0;
+}
+
+static void ot_perf_report(struct ot_test *test, u64 duration)
+{
+ struct ot_obj_stat total, normal = {0}, irq = {0};
+ int cpu, nthreads = 0;
+
+ pr_info("\n");
+ pr_info("Testing summary for %s\n", test->name);
+
+ for_each_possible_cpu(cpu) {
+ struct ot_item *item = per_cpu_ptr(&ot_pcup_items, cpu);
+ if (!item->duration)
+ continue;
+ normal.nhits += item->stat[0].nhits;
+ normal.nmiss += item->stat[0].nmiss;
+ irq.nhits += item->stat[1].nhits;
+ irq.nmiss += item->stat[1].nmiss;
+ pr_info("CPU: %d duration: %lluus\n", cpu, item->duration);
+ pr_info("\tthread:\t%16lu hits \t%16lu miss\n",
+ item->stat[0].nhits, item->stat[0].nmiss);
+ pr_info("\tirq: \t%16lu hits \t%16lu miss\n",
+ item->stat[1].nhits, item->stat[1].nmiss);
+ pr_info("\ttotal: \t%16lu hits \t%16lu miss\n",
+ item->stat[0].nhits + item->stat[1].nhits,
+ item->stat[0].nmiss + item->stat[1].nmiss);
+ nthreads++;
+ }
+
+ total.nhits = normal.nhits + irq.nhits;
+ total.nmiss = normal.nmiss + irq.nmiss;
+
+ pr_info("ALL: \tnthreads: %d duration: %lluus\n", nthreads, duration);
+ pr_info("SUM: \t%16lu hits \t%16lu miss\n",
+ total.nhits, total.nmiss);
+
+ test->data.objects = total;
+ test->data.duration = duration;
+}
+
+/*
+ * synchronous test cases for objpool manipulation
+ */
+
+/* objpool manipulation for synchronous mode (percpu objpool) */
+static struct ot_context *ot_init_sync_m0(struct ot_test *test)
+{
+ struct ot_context *sop = NULL;
+ int max = num_possible_cpus() << 3;
+ gfp_t gfp = GFP_KERNEL;
+
+ sop = (struct ot_context *)ot_kzalloc(test, sizeof(*sop));
+ if (!sop)
+ return NULL;
+ sop->test = test;
+ if (test->objsz < 512)
+ gfp = GFP_ATOMIC;
+
+ if (objpool_init(&sop->pool, max, test->objsz,
+ gfp, sop, ot_init_node, NULL)) {
+ ot_kfree(test, sop, sizeof(*sop));
+ return NULL;
+ }
+ WARN_ON(max != sop->pool.nr_objs);
+
+ return sop;
+}
+
+static void ot_fini_sync(struct ot_context *sop)
+{
+ objpool_fini(&sop->pool);
+ ot_kfree(sop->test, sop, sizeof(*sop));
+}
+
+struct {
+ struct ot_context * (*init)(struct ot_test *oc);
+ void (*fini)(struct ot_context *sop);
+} g_ot_sync_ops[] = {
+ {.init = ot_init_sync_m0, .fini = ot_fini_sync},
+};
+
+/*
+ * synchronous test cases: performance mode
+ */
+
+static void ot_bulk_sync(struct ot_item *item, int irq)
+{
+ struct ot_node *nods[OT_NR_MAX_BULK];
+ int i;
+
+ for (i = 0; i < item->bulk[irq]; i++)
+ nods[i] = objpool_pop(item->pool);
+
+ if (!irq && (item->delay || !(++(item->niters) & 0x7FFF)))
+ msleep(item->delay);
+
+ while (i-- > 0) {
+ struct ot_node *on = nods[i];
+ if (on) {
+ on->refs++;
+ objpool_push(on, item->pool);
+ item->stat[irq].nhits++;
+ } else {
+ item->stat[irq].nmiss++;
+ }
+ }
+}
+
+static int ot_start_sync(struct ot_test *test)
+{
+ struct ot_context *sop;
+ ktime_t start;
+ u64 duration;
+ unsigned long timeout;
+ int cpu;
+
+ /* initialize objpool for syncrhonous testcase */
+ sop = g_ot_sync_ops[test->mode].init(test);
+ if (!sop)
+ return -ENOMEM;
+
+ /* grab rwsem to block testing threads */
+ down_write(&test->data.start);
+
+ for_each_possible_cpu(cpu) {
+ struct ot_item *item = per_cpu_ptr(&ot_pcup_items, cpu);
+ struct task_struct *work;
+
+ ot_init_cpu_item(item, test, &sop->pool, ot_bulk_sync);
+
+ /* skip offline cpus */
+ if (!cpu_online(cpu))
+ continue;
+
+ work = kthread_create_on_node(ot_thread_worker, item,
+ cpu_to_node(cpu), "ot_worker_%d", cpu);
+ if (IS_ERR(work)) {
+ pr_err("failed to create thread for cpu %d\n", cpu);
+ } else {
+ kthread_bind(work, cpu);
+ wake_up_process(work);
+ }
+ }
+
+ /* wait a while to make sure all threads waiting at start line */
+ msleep(20);
+
+ /* in case no threads were created: memory insufficient ? */
+ if (atomic_dec_and_test(&test->data.nthreads))
+ complete(&test->data.wait);
+
+ // sched_set_fifo_low(current);
+
+ /* start objpool testing threads */
+ start = ktime_get();
+ up_write(&test->data.start);
+
+ /* yeild cpu to worker threads for duration ms */
+ timeout = msecs_to_jiffies(test->duration);
+ schedule_timeout_interruptible(timeout);
+
+ /* tell workers threads to quit */
+ atomic_set_release(&test->data.stop, 1);
+
+ /* wait all workers threads finish and quit */
+ wait_for_completion(&test->data.wait);
+ duration = (u64) ktime_us_delta(ktime_get(), start);
+
+ /* cleanup objpool */
+ g_ot_sync_ops[test->mode].fini(sop);
+
+ /* report testing summary and performance results */
+ ot_perf_report(test, duration);
+
+ /* report memory allocation summary */
+ ot_mem_report(test);
+
+ return 0;
+}
+
+/*
+ * asynchronous test cases: pool lifecycle controlled by refcount
+ */
+
+static void ot_fini_async_rcu(struct rcu_head *rcu)
+{
+ struct ot_context *sop = container_of(rcu, struct ot_context, rcu);
+ struct ot_test *test = sop->test;
+
+ /* here all cpus are aware of the stop event: test->data.stop = 1 */
+ WARN_ON(!atomic_read_acquire(&test->data.stop));
+
+ objpool_fini(&sop->pool);
+ complete(&test->data.rcu);
+}
+
+static void ot_fini_async(struct ot_context *sop)
+{
+ /* make sure the stop event is acknowledged by all cores */
+ call_rcu(&sop->rcu, ot_fini_async_rcu);
+}
+
+static int ot_objpool_release(struct objpool_head *head, void *context)
+{
+ struct ot_context *sop = context;
+
+ WARN_ON(!head || !sop || head != &sop->pool);
+
+ /* do context cleaning if needed */
+ if (sop)
+ ot_kfree(sop->test, sop, sizeof(*sop));
+
+ return 0;
+}
+
+static struct ot_context *ot_init_async_m0(struct ot_test *test)
+{
+ struct ot_context *sop = NULL;
+ int max = num_possible_cpus() << 3;
+ gfp_t gfp = GFP_KERNEL;
+
+ sop = (struct ot_context *)ot_kzalloc(test, sizeof(*sop));
+ if (!sop)
+ return NULL;
+ sop->test = test;
+ if (test->objsz < 512)
+ gfp = GFP_ATOMIC;
+
+ if (objpool_init(&sop->pool, max, test->objsz, gfp, sop,
+ ot_init_node, ot_objpool_release)) {
+ ot_kfree(test, sop, sizeof(*sop));
+ return NULL;
+ }
+ WARN_ON(max != sop->pool.nr_objs);
+
+ return sop;
+}
+
+struct {
+ struct ot_context * (*init)(struct ot_test *oc);
+ void (*fini)(struct ot_context *sop);
+} g_ot_async_ops[] = {
+ {.init = ot_init_async_m0, .fini = ot_fini_async},
+};
+
+static void ot_nod_recycle(struct ot_node *on, struct objpool_head *pool,
+ int release)
+{
+ struct ot_context *sop;
+
+ on->refs++;
+
+ if (!release) {
+ /* push object back to opjpool for reuse */
+ objpool_push(on, pool);
+ return;
+ }
+
+ sop = container_of(pool, struct ot_context, pool);
+ WARN_ON(sop != pool->context);
+
+ /* unref objpool with nod removed forever */
+ objpool_drop(on, pool);
+}
+
+static void ot_bulk_async(struct ot_item *item, int irq)
+{
+ struct ot_test *test = item->test;
+ struct ot_node *nods[OT_NR_MAX_BULK];
+ int i, stop;
+
+ for (i = 0; i < item->bulk[irq]; i++)
+ nods[i] = objpool_pop(item->pool);
+
+ if (!irq) {
+ if (item->delay || !(++(item->niters) & 0x7FFF))
+ msleep(item->delay);
+ get_cpu();
+ }
+
+ stop = atomic_read_acquire(&test->data.stop);
+
+ /* drop all objects and deref objpool */
+ while (i-- > 0) {
+ struct ot_node *on = nods[i];
+
+ if (on) {
+ on->refs++;
+ ot_nod_recycle(on, item->pool, stop);
+ item->stat[irq].nhits++;
+ } else {
+ item->stat[irq].nmiss++;
+ }
+ }
+
+ if (!irq)
+ put_cpu();
+}
+
+static int ot_start_async(struct ot_test *test)
+{
+ struct ot_context *sop;
+ ktime_t start;
+ u64 duration;
+ unsigned long timeout;
+ int cpu;
+
+ /* initialize objpool for syncrhonous testcase */
+ sop = g_ot_async_ops[test->mode].init(test);
+ if (!sop)
+ return -ENOMEM;
+
+ /* grab rwsem to block testing threads */
+ down_write(&test->data.start);
+
+ for_each_possible_cpu(cpu) {
+ struct ot_item *item = per_cpu_ptr(&ot_pcup_items, cpu);
+ struct task_struct *work;
+
+ ot_init_cpu_item(item, test, &sop->pool, ot_bulk_async);
+
+ /* skip offline cpus */
+ if (!cpu_online(cpu))
+ continue;
+
+ work = kthread_create_on_node(ot_thread_worker, item,
+ cpu_to_node(cpu), "ot_worker_%d", cpu);
+ if (IS_ERR(work)) {
+ pr_err("failed to create thread for cpu %d\n", cpu);
+ } else {
+ kthread_bind(work, cpu);
+ wake_up_process(work);
+ }
+ }
+
+ /* wait a while to make sure all threads waiting at start line */
+ msleep(20);
+
+ /* in case no threads were created: memory insufficient ? */
+ if (atomic_dec_and_test(&test->data.nthreads))
+ complete(&test->data.wait);
+
+ /* start objpool testing threads */
+ start = ktime_get();
+ up_write(&test->data.start);
+
+ /* yeild cpu to worker threads for duration ms */
+ timeout = msecs_to_jiffies(test->duration);
+ schedule_timeout_interruptible(timeout);
+
+ /* tell workers threads to quit */
+ atomic_set_release(&test->data.stop, 1);
+
+ /* do async-finalization */
+ g_ot_async_ops[test->mode].fini(sop);
+
+ /* wait all workers threads finish and quit */
+ wait_for_completion(&test->data.wait);
+ duration = (u64) ktime_us_delta(ktime_get(), start);
+
+ /* assure rcu callback is triggered */
+ wait_for_completion(&test->data.rcu);
+
+ /*
+ * now we are sure that objpool is finalized either
+ * by rcu callback or by worker threads
+ */
+
+ /* report testing summary and performance results */
+ ot_perf_report(test, duration);
+
+ /* report memory allocation summary */
+ ot_mem_report(test);
+
+ return 0;
+}
+
+/*
+ * predefined testing cases:
+ * synchronous case / overrun case / async case
+ *
+ * async: synchronous or asynchronous testing
+ * mode: only mode 0 supported
+ * objsz: object size
+ * duration: int, total test time in ms
+ * delay: int, delay (in ms) between each iteration
+ * bulk_normal: int, repeat times for thread worker
+ * bulk_irq: int, repeat times for irq consumer
+ * hrtimer: unsigned long, hrtimer intervnal in ms
+ * name: char *, tag for current test ot_item
+ */
+
+#define NODE_COMPACT sizeof(struct ot_node)
+#define NODE_VMALLOC (512)
+
+struct ot_test g_testcases[] = {
+
+ /* sync & normal */
+ {0, 0, NODE_COMPACT, 1000, 0, 1, 0, 0, "sync: percpu objpool"},
+ {0, 0, NODE_VMALLOC, 1000, 0, 1, 0, 0, "sync: percpu objpool from vmalloc"},
+
+ /* sync & hrtimer */
+ {0, 0, NODE_COMPACT, 1000, 0, 1, 1, 4, "sync & hrtimer: percpu objpool"},
+ {0, 0, NODE_VMALLOC, 1000, 0, 1, 1, 4, "sync & hrtimer: percpu objpool from vmalloc"},
+
+ /* sync & overrun */
+ {0, 0, NODE_COMPACT, 1000, 0, 16, 0, 0, "sync overrun: percpu objpool"},
+ {0, 0, NODE_VMALLOC, 1000, 0, 16, 0, 0, "sync overrun: percpu objpool from vmalloc"},
+
+ /* async mode */
+ {1, 0, NODE_COMPACT, 1000, 100, 1, 0, 0, "async: percpu objpool"},
+ {1, 0, NODE_VMALLOC, 1000, 100, 1, 0, 0, "async: percpu objpool from vmalloc"},
+
+ /* async + hrtimer mode */
+ {1, 0, NODE_COMPACT, 1000, 0, 4, 4, 4, "async & hrtimer: percpu objpool"},
+ {1, 0, NODE_VMALLOC, 1000, 0, 4, 4, 4, "async & hrtimer: percpu objpool from vmalloc"},
+};
+
+static int __init ot_mod_init(void)
+{
+ int i;
+
+ /* perform testings */
+ for (i = 0; i < ARRAY_SIZE(g_testcases); i++) {
+ ot_init_data(&g_testcases[i].data);
+ if (g_testcases[i].async)
+ ot_start_async(&g_testcases[i]);
+ else
+ ot_start_sync(&g_testcases[i]);
+ }
+
+ /* show tests summary */
+ pr_info("\n");
+ pr_info("Summary of testcases:\n");
+ for (i = 0; i < ARRAY_SIZE(g_testcases); i++) {
+ pr_info(" duration: %lluus \thits: %10lu \tmiss: %10lu \t%s\n",
+ g_testcases[i].data.duration, g_testcases[i].data.objects.nhits,
+ g_testcases[i].data.objects.nmiss, g_testcases[i].name);
+ }
+
+ return -EAGAIN;
+}
+
+static void __exit ot_mod_exit(void)
+{
+}
+
+module_init(ot_mod_init);
+module_exit(ot_mod_exit);
+
+MODULE_LICENSE("GPL");
\ No newline at end of file
diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c
index cbf1654..ed79fd3 100644
--- a/samples/kprobes/kretprobe_example.c
+++ b/samples/kprobes/kretprobe_example.c
@@ -35,7 +35,7 @@ struct my_data {
ktime_t entry_stamp;
};
-/* Here we use the entry_hanlder to timestamp function entry */
+/* Here we use the entry_handler to timestamp function entry */
static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
struct my_data *data;
