io_uring: move to using create_io_thread()
This allows us to do task creation and setup without needing to use
completions to try and synchronize with the starting thread. Get rid of
the old io_wq_fork_thread() wrapper, and the 'wq' and 'worker' startup
completion events - we can now do setup before the task is running.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 19f1838..d7cfe8f 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -54,7 +54,6 @@ struct io_worker {
spinlock_t lock;
struct completion ref_done;
- struct completion started;
struct rcu_head rcu;
};
@@ -116,7 +115,6 @@ struct io_wq {
struct io_wq_hash *hash;
refcount_t refs;
- struct completion started;
struct completion exited;
atomic_t worker_refs;
@@ -199,6 +197,7 @@ static void io_worker_exit(struct io_worker *worker)
kfree_rcu(worker, rcu);
if (atomic_dec_and_test(&wqe->wq->worker_refs))
complete(&wqe->wq->worker_done);
+ do_exit(0);
}
static inline bool io_wqe_run_queue(struct io_wqe *wqe)
@@ -273,14 +272,6 @@ static void io_wqe_dec_running(struct io_worker *worker)
io_wqe_wake_worker(wqe, acct);
}
-static void io_worker_start(struct io_worker *worker)
-{
- current->flags |= PF_NOFREEZE;
- worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
- io_wqe_inc_running(worker);
- complete(&worker->started);
-}
-
/*
* Worker will start processing some work. Move it to the busy list, if
* it's currently on the freelist
@@ -489,8 +480,13 @@ static int io_wqe_worker(void *data)
struct io_worker *worker = data;
struct io_wqe *wqe = worker->wqe;
struct io_wq *wq = wqe->wq;
+ char buf[TASK_COMM_LEN];
- io_worker_start(worker);
+ worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
+ io_wqe_inc_running(worker);
+
+ sprintf(buf, "iou-wrk-%d", wq->task_pid);
+ set_task_comm(current, buf);
while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
set_current_state(TASK_INTERRUPTIBLE);
@@ -565,67 +561,11 @@ void io_wq_worker_sleeping(struct task_struct *tsk)
raw_spin_unlock_irq(&worker->wqe->lock);
}
-static int task_thread(void *data, int index)
-{
- struct io_worker *worker = data;
- struct io_wqe *wqe = worker->wqe;
- struct io_wqe_acct *acct = &wqe->acct[index];
- struct io_wq *wq = wqe->wq;
- char buf[TASK_COMM_LEN];
-
- sprintf(buf, "iou-wrk-%d", wq->task_pid);
- set_task_comm(current, buf);
-
- current->pf_io_worker = worker;
- worker->task = current;
-
- set_cpus_allowed_ptr(current, cpumask_of_node(wqe->node));
- current->flags |= PF_NO_SETAFFINITY;
-
- raw_spin_lock_irq(&wqe->lock);
- hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
- list_add_tail_rcu(&worker->all_list, &wqe->all_list);
- worker->flags |= IO_WORKER_F_FREE;
- if (index == IO_WQ_ACCT_BOUND)
- worker->flags |= IO_WORKER_F_BOUND;
- if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND))
- worker->flags |= IO_WORKER_F_FIXED;
- acct->nr_workers++;
- raw_spin_unlock_irq(&wqe->lock);
-
- io_wqe_worker(data);
- do_exit(0);
-}
-
-static int task_thread_bound(void *data)
-{
- return task_thread(data, IO_WQ_ACCT_BOUND);
-}
-
-static int task_thread_unbound(void *data)
-{
- return task_thread(data, IO_WQ_ACCT_UNBOUND);
-}
-
-pid_t io_wq_fork_thread(int (*fn)(void *), void *arg)
-{
- unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|
- CLONE_IO|SIGCHLD;
- struct kernel_clone_args args = {
- .flags = ((lower_32_bits(flags) | CLONE_VM |
- CLONE_UNTRACED) & ~CSIGNAL),
- .exit_signal = (lower_32_bits(flags) & CSIGNAL),
- .stack = (unsigned long)fn,
- .stack_size = (unsigned long)arg,
- };
-
- return kernel_clone(&args);
-}
-
static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
{
+ struct io_wqe_acct *acct = &wqe->acct[index];
struct io_worker *worker;
- pid_t pid;
+ struct task_struct *tsk;
__set_current_state(TASK_RUNNING);
@@ -638,21 +578,33 @@ static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
worker->wqe = wqe;
spin_lock_init(&worker->lock);
init_completion(&worker->ref_done);
- init_completion(&worker->started);
atomic_inc(&wq->worker_refs);
- if (index == IO_WQ_ACCT_BOUND)
- pid = io_wq_fork_thread(task_thread_bound, worker);
- else
- pid = io_wq_fork_thread(task_thread_unbound, worker);
- if (pid < 0) {
+ tsk = create_io_thread(io_wqe_worker, worker, wqe->node);
+ if (IS_ERR(tsk)) {
if (atomic_dec_and_test(&wq->worker_refs))
complete(&wq->worker_done);
kfree(worker);
return false;
}
- wait_for_completion(&worker->started);
+
+ tsk->pf_io_worker = worker;
+ worker->task = tsk;
+ set_cpus_allowed_ptr(tsk, cpumask_of_node(wqe->node));
+ tsk->flags |= PF_NOFREEZE | PF_NO_SETAFFINITY;
+
+ raw_spin_lock_irq(&wqe->lock);
+ hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
+ list_add_tail_rcu(&worker->all_list, &wqe->all_list);
+ worker->flags |= IO_WORKER_F_FREE;
+ if (index == IO_WQ_ACCT_BOUND)
+ worker->flags |= IO_WORKER_F_BOUND;
+ if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND))
+ worker->flags |= IO_WORKER_F_FIXED;
+ acct->nr_workers++;
+ raw_spin_unlock_irq(&wqe->lock);
+ wake_up_new_task(tsk);
return true;
}
@@ -696,6 +648,7 @@ static bool io_wq_for_each_worker(struct io_wqe *wqe,
static bool io_wq_worker_wake(struct io_worker *worker, void *data)
{
+ set_notify_signal(worker->task);
wake_up_process(worker->task);
return false;
}
@@ -752,10 +705,6 @@ static int io_wq_manager(void *data)
sprintf(buf, "iou-mgr-%d", wq->task_pid);
set_task_comm(current, buf);
- current->flags |= PF_IO_WORKER;
- wq->manager = get_task_struct(current);
-
- complete(&wq->started);
do {
set_current_state(TASK_INTERRUPTIBLE);
@@ -815,21 +764,20 @@ static void io_wqe_insert_work(struct io_wqe *wqe, struct io_wq_work *work)
static int io_wq_fork_manager(struct io_wq *wq)
{
- int ret;
+ struct task_struct *tsk;
if (wq->manager)
return 0;
reinit_completion(&wq->worker_done);
- current->flags |= PF_IO_WORKER;
- ret = io_wq_fork_thread(io_wq_manager, wq);
- current->flags &= ~PF_IO_WORKER;
- if (ret >= 0) {
- wait_for_completion(&wq->started);
+ tsk = create_io_thread(io_wq_manager, wq, NUMA_NO_NODE);
+ if (!IS_ERR(tsk)) {
+ wq->manager = get_task_struct(tsk);
+ wake_up_new_task(tsk);
return 0;
}
- return ret;
+ return PTR_ERR(tsk);
}
static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
@@ -1062,7 +1010,6 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
}
wq->task_pid = current->pid;
- init_completion(&wq->started);
init_completion(&wq->exited);
refcount_set(&wq->refs, 1);
diff --git a/fs/io-wq.h b/fs/io-wq.h
index 42f0be6..5fbf799 100644
--- a/fs/io-wq.h
+++ b/fs/io-wq.h
@@ -119,8 +119,6 @@ void io_wq_put_and_exit(struct io_wq *wq);
void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work);
void io_wq_hash_work(struct io_wq_work *work, void *val);
-pid_t io_wq_fork_thread(int (*fn)(void *), void *arg);
-
static inline bool io_wq_is_hashed(struct io_wq_work *work)
{
return work->flags & IO_WQ_WORK_HASHED;
diff --git a/fs/io_uring.c b/fs/io_uring.c
index e553695..76e243c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6668,7 +6668,6 @@ static int io_sq_thread(void *data)
sprintf(buf, "iou-sqp-%d", sqd->task_pid);
set_task_comm(current, buf);
- sqd->thread = current;
current->pf_io_worker = NULL;
if (sqd->sq_cpu != -1)
@@ -6677,8 +6676,6 @@ static int io_sq_thread(void *data)
set_cpus_allowed_ptr(current, cpu_online_mask);
current->flags |= PF_NO_SETAFFINITY;
- complete(&sqd->completion);
-
wait_for_completion(&sqd->startup);
while (!io_sq_thread_should_stop(sqd)) {
@@ -7818,21 +7815,22 @@ void __io_uring_free(struct task_struct *tsk)
static int io_sq_thread_fork(struct io_sq_data *sqd, struct io_ring_ctx *ctx)
{
+ struct task_struct *tsk;
int ret;
clear_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
reinit_completion(&sqd->completion);
ctx->sqo_exec = 0;
sqd->task_pid = current->pid;
- current->flags |= PF_IO_WORKER;
- ret = io_wq_fork_thread(io_sq_thread, sqd);
- current->flags &= ~PF_IO_WORKER;
- if (ret < 0) {
- sqd->thread = NULL;
- return ret;
- }
- wait_for_completion(&sqd->completion);
- return io_uring_alloc_task_context(sqd->thread, ctx);
+ tsk = create_io_thread(io_sq_thread, sqd, NUMA_NO_NODE);
+ if (IS_ERR(tsk))
+ return PTR_ERR(tsk);
+ ret = io_uring_alloc_task_context(tsk, ctx);
+ if (ret)
+ set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
+ sqd->thread = tsk;
+ wake_up_new_task(tsk);
+ return ret;
}
static int io_sq_offload_create(struct io_ring_ctx *ctx,
@@ -7855,6 +7853,7 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx,
fdput(f);
}
if (ctx->flags & IORING_SETUP_SQPOLL) {
+ struct task_struct *tsk;
struct io_sq_data *sqd;
ret = -EPERM;
@@ -7896,15 +7895,16 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx,
}
sqd->task_pid = current->pid;
- current->flags |= PF_IO_WORKER;
- ret = io_wq_fork_thread(io_sq_thread, sqd);
- current->flags &= ~PF_IO_WORKER;
- if (ret < 0) {
- sqd->thread = NULL;
+ tsk = create_io_thread(io_sq_thread, sqd, NUMA_NO_NODE);
+ if (IS_ERR(tsk)) {
+ ret = PTR_ERR(tsk);
goto err;
}
- wait_for_completion(&sqd->completion);
- ret = io_uring_alloc_task_context(sqd->thread, ctx);
+ ret = io_uring_alloc_task_context(tsk, ctx);
+ if (ret)
+ set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
+ sqd->thread = tsk;
+ wake_up_new_task(tsk);
if (ret)
goto err;
} else if (p->flags & IORING_SETUP_SQ_AFF) {
