1 // SPDX-License-Identifier: GPL-2.0
3 * Basic worker thread pool for io_uring
5 * Copyright (C) 2019 Jens Axboe
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/errno.h>
11 #include <linux/sched/signal.h>
12 #include <linux/percpu.h>
13 #include <linux/slab.h>
14 #include <linux/rculist_nulls.h>
15 #include <linux/cpu.h>
16 #include <linux/tracehook.h>
20 #define WORKER_IDLE_TIMEOUT (5 * HZ)
23 IO_WORKER_F_UP = 1, /* up and active */
24 IO_WORKER_F_RUNNING = 2, /* account as running */
25 IO_WORKER_F_FREE = 4, /* worker on free list */
26 IO_WORKER_F_FIXED = 8, /* static idle worker */
27 IO_WORKER_F_BOUND = 16, /* is doing bounded work */
31 IO_WQ_BIT_EXIT = 0, /* wq exiting */
35 IO_WQE_FLAG_STALLED = 1, /* stalled on hash */
39 * One for each thread in a wqe pool
44 struct hlist_nulls_node nulls_node;
45 struct list_head all_list;
46 struct task_struct *task;
49 struct io_wq_work *cur_work;
52 struct completion ref_done;
57 #if BITS_PER_LONG == 64
58 #define IO_WQ_HASH_ORDER 6
60 #define IO_WQ_HASH_ORDER 5
63 #define IO_WQ_NR_HASH_BUCKETS (1u << IO_WQ_HASH_ORDER)
78 * Per-node worker thread pool
83 struct io_wq_work_list work_list;
85 } ____cacheline_aligned_in_smp;
88 struct io_wqe_acct acct[2];
90 struct hlist_nulls_head free_list;
91 struct list_head all_list;
93 struct wait_queue_entry wait;
96 struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS];
98 cpumask_var_t cpu_mask;
107 free_work_fn *free_work;
108 io_wq_work_fn *do_work;
110 struct io_wq_hash *hash;
112 atomic_t worker_refs;
113 struct completion worker_done;
115 struct hlist_node cpuhp_node;
117 struct task_struct *task;
119 struct io_wqe *wqes[];
122 static enum cpuhp_state io_wq_online;
124 struct io_cb_cancel_data {
132 static void create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index);
134 static bool io_worker_get(struct io_worker *worker)
136 return refcount_inc_not_zero(&worker->ref);
139 static void io_worker_release(struct io_worker *worker)
141 if (refcount_dec_and_test(&worker->ref))
142 complete(&worker->ref_done);
145 static inline struct io_wqe_acct *io_get_acct(struct io_wqe *wqe, bool bound)
147 return &wqe->acct[bound ? IO_WQ_ACCT_BOUND : IO_WQ_ACCT_UNBOUND];
150 static inline struct io_wqe_acct *io_work_get_acct(struct io_wqe *wqe,
151 struct io_wq_work *work)
153 return io_get_acct(wqe, !(work->flags & IO_WQ_WORK_UNBOUND));
156 static inline struct io_wqe_acct *io_wqe_get_acct(struct io_worker *worker)
158 return io_get_acct(worker->wqe, worker->flags & IO_WORKER_F_BOUND);
161 static void io_worker_ref_put(struct io_wq *wq)
163 if (atomic_dec_and_test(&wq->worker_refs))
164 complete(&wq->worker_done);
167 static void io_worker_exit(struct io_worker *worker)
169 struct io_wqe *wqe = worker->wqe;
170 struct io_wqe_acct *acct = io_wqe_get_acct(worker);
173 if (refcount_dec_and_test(&worker->ref))
174 complete(&worker->ref_done);
175 wait_for_completion(&worker->ref_done);
178 current->flags &= ~PF_IO_WORKER;
179 flags = worker->flags;
181 if (flags & IO_WORKER_F_RUNNING)
182 atomic_dec(&acct->nr_running);
186 raw_spin_lock_irq(&wqe->lock);
187 if (flags & IO_WORKER_F_FREE)
188 hlist_nulls_del_rcu(&worker->nulls_node);
189 list_del_rcu(&worker->all_list);
191 raw_spin_unlock_irq(&wqe->lock);
193 kfree_rcu(worker, rcu);
194 io_worker_ref_put(wqe->wq);
198 static inline bool io_wqe_run_queue(struct io_wqe *wqe)
199 __must_hold(wqe->lock)
201 if (!wq_list_empty(&wqe->work_list) &&
202 !(wqe->flags & IO_WQE_FLAG_STALLED))
208 * Check head of free list for an available worker. If one isn't available,
209 * caller must create one.
211 static bool io_wqe_activate_free_worker(struct io_wqe *wqe)
214 struct hlist_nulls_node *n;
215 struct io_worker *worker;
217 n = rcu_dereference(hlist_nulls_first_rcu(&wqe->free_list));
221 worker = hlist_nulls_entry(n, struct io_worker, nulls_node);
222 if (io_worker_get(worker)) {
223 wake_up_process(worker->task);
224 io_worker_release(worker);
232 * We need a worker. If we find a free one, we're good. If not, and we're
233 * below the max number of workers, create one.
235 static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
240 * Most likely an attempt to queue unbounded work on an io_wq that
241 * wasn't setup with any unbounded workers.
243 if (unlikely(!acct->max_workers))
244 pr_warn_once("io-wq is not configured for unbound workers");
247 ret = io_wqe_activate_free_worker(wqe);
250 if (!ret && acct->nr_workers < acct->max_workers) {
251 atomic_inc(&acct->nr_running);
252 atomic_inc(&wqe->wq->worker_refs);
253 create_io_worker(wqe->wq, wqe, acct->index);
257 static void io_wqe_inc_running(struct io_worker *worker)
259 struct io_wqe_acct *acct = io_wqe_get_acct(worker);
261 atomic_inc(&acct->nr_running);
264 struct create_worker_data {
265 struct callback_head work;
270 static void create_worker_cb(struct callback_head *cb)
272 struct create_worker_data *cwd;
275 cwd = container_of(cb, struct create_worker_data, work);
277 create_io_worker(wq, cwd->wqe, cwd->index);
281 static void io_queue_worker_create(struct io_wqe *wqe, struct io_wqe_acct *acct)
283 struct create_worker_data *cwd;
284 struct io_wq *wq = wqe->wq;
286 /* raced with exit, just ignore create call */
287 if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
290 cwd = kmalloc(sizeof(*cwd), GFP_ATOMIC);
292 init_task_work(&cwd->work, create_worker_cb);
294 cwd->index = acct->index;
295 if (!task_work_add(wq->task, &cwd->work, TWA_SIGNAL))
301 atomic_dec(&acct->nr_running);
302 io_worker_ref_put(wq);
305 static void io_wqe_dec_running(struct io_worker *worker)
306 __must_hold(wqe->lock)
308 struct io_wqe_acct *acct = io_wqe_get_acct(worker);
309 struct io_wqe *wqe = worker->wqe;
311 if (!(worker->flags & IO_WORKER_F_UP))
314 if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe)) {
315 atomic_inc(&acct->nr_running);
316 atomic_inc(&wqe->wq->worker_refs);
317 io_queue_worker_create(wqe, acct);
322 * Worker will start processing some work. Move it to the busy list, if
323 * it's currently on the freelist
325 static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
326 struct io_wq_work *work)
327 __must_hold(wqe->lock)
329 bool worker_bound, work_bound;
331 BUILD_BUG_ON((IO_WQ_ACCT_UNBOUND ^ IO_WQ_ACCT_BOUND) != 1);
333 if (worker->flags & IO_WORKER_F_FREE) {
334 worker->flags &= ~IO_WORKER_F_FREE;
335 hlist_nulls_del_init_rcu(&worker->nulls_node);
339 * If worker is moving from bound to unbound (or vice versa), then
340 * ensure we update the running accounting.
342 worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
343 work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
344 if (worker_bound != work_bound) {
345 int index = work_bound ? IO_WQ_ACCT_UNBOUND : IO_WQ_ACCT_BOUND;
346 io_wqe_dec_running(worker);
347 worker->flags ^= IO_WORKER_F_BOUND;
348 wqe->acct[index].nr_workers--;
349 wqe->acct[index ^ 1].nr_workers++;
350 io_wqe_inc_running(worker);
355 * No work, worker going to sleep. Move to freelist, and unuse mm if we
356 * have one attached. Dropping the mm may potentially sleep, so we drop
357 * the lock in that case and return success. Since the caller has to
358 * retry the loop in that case (we changed task state), we don't regrab
359 * the lock if we return success.
361 static void __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker)
362 __must_hold(wqe->lock)
364 if (!(worker->flags & IO_WORKER_F_FREE)) {
365 worker->flags |= IO_WORKER_F_FREE;
366 hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
370 static inline unsigned int io_get_work_hash(struct io_wq_work *work)
372 return work->flags >> IO_WQ_HASH_SHIFT;
375 static void io_wait_on_hash(struct io_wqe *wqe, unsigned int hash)
377 struct io_wq *wq = wqe->wq;
379 spin_lock(&wq->hash->wait.lock);
380 if (list_empty(&wqe->wait.entry)) {
381 __add_wait_queue(&wq->hash->wait, &wqe->wait);
382 if (!test_bit(hash, &wq->hash->map)) {
383 __set_current_state(TASK_RUNNING);
384 list_del_init(&wqe->wait.entry);
387 spin_unlock(&wq->hash->wait.lock);
390 static struct io_wq_work *io_get_next_work(struct io_wqe *wqe)
391 __must_hold(wqe->lock)
393 struct io_wq_work_node *node, *prev;
394 struct io_wq_work *work, *tail;
395 unsigned int stall_hash = -1U;
397 wq_list_for_each(node, prev, &wqe->work_list) {
400 work = container_of(node, struct io_wq_work, list);
402 /* not hashed, can run anytime */
403 if (!io_wq_is_hashed(work)) {
404 wq_list_del(&wqe->work_list, node, prev);
408 hash = io_get_work_hash(work);
409 /* all items with this hash lie in [work, tail] */
410 tail = wqe->hash_tail[hash];
412 /* hashed, can run if not already running */
413 if (!test_and_set_bit(hash, &wqe->wq->hash->map)) {
414 wqe->hash_tail[hash] = NULL;
415 wq_list_cut(&wqe->work_list, &tail->list, prev);
418 if (stall_hash == -1U)
420 /* fast forward to a next hash, for-each will fix up @prev */
424 if (stall_hash != -1U) {
425 raw_spin_unlock(&wqe->lock);
426 io_wait_on_hash(wqe, stall_hash);
427 raw_spin_lock(&wqe->lock);
433 static bool io_flush_signals(void)
435 if (unlikely(test_thread_flag(TIF_NOTIFY_SIGNAL))) {
436 __set_current_state(TASK_RUNNING);
437 tracehook_notify_signal();
443 static void io_assign_current_work(struct io_worker *worker,
444 struct io_wq_work *work)
451 spin_lock_irq(&worker->lock);
452 worker->cur_work = work;
453 spin_unlock_irq(&worker->lock);
456 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work);
458 static void io_worker_handle_work(struct io_worker *worker)
459 __releases(wqe->lock)
461 struct io_wqe *wqe = worker->wqe;
462 struct io_wq *wq = wqe->wq;
463 bool do_kill = test_bit(IO_WQ_BIT_EXIT, &wq->state);
466 struct io_wq_work *work;
469 * If we got some work, mark us as busy. If we didn't, but
470 * the list isn't empty, it means we stalled on hashed work.
471 * Mark us stalled so we don't keep looking for work when we
472 * can't make progress, any work completion or insertion will
473 * clear the stalled flag.
475 work = io_get_next_work(wqe);
477 __io_worker_busy(wqe, worker, work);
478 else if (!wq_list_empty(&wqe->work_list))
479 wqe->flags |= IO_WQE_FLAG_STALLED;
481 raw_spin_unlock_irq(&wqe->lock);
484 io_assign_current_work(worker, work);
485 __set_current_state(TASK_RUNNING);
487 /* handle a whole dependent link */
489 struct io_wq_work *next_hashed, *linked;
490 unsigned int hash = io_get_work_hash(work);
492 next_hashed = wq_next_work(work);
494 if (unlikely(do_kill) && (work->flags & IO_WQ_WORK_UNBOUND))
495 work->flags |= IO_WQ_WORK_CANCEL;
497 io_assign_current_work(worker, NULL);
499 linked = wq->free_work(work);
501 if (!work && linked && !io_wq_is_hashed(linked)) {
505 io_assign_current_work(worker, work);
507 io_wqe_enqueue(wqe, linked);
509 if (hash != -1U && !next_hashed) {
510 clear_bit(hash, &wq->hash->map);
511 if (wq_has_sleeper(&wq->hash->wait))
512 wake_up(&wq->hash->wait);
513 raw_spin_lock_irq(&wqe->lock);
514 wqe->flags &= ~IO_WQE_FLAG_STALLED;
515 /* skip unnecessary unlock-lock wqe->lock */
518 raw_spin_unlock_irq(&wqe->lock);
522 raw_spin_lock_irq(&wqe->lock);
526 static int io_wqe_worker(void *data)
528 struct io_worker *worker = data;
529 struct io_wqe *wqe = worker->wqe;
530 struct io_wq *wq = wqe->wq;
531 char buf[TASK_COMM_LEN];
533 worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
535 snprintf(buf, sizeof(buf), "iou-wrk-%d", wq->task->pid);
536 set_task_comm(current, buf);
538 while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
541 set_current_state(TASK_INTERRUPTIBLE);
543 raw_spin_lock_irq(&wqe->lock);
544 if (io_wqe_run_queue(wqe)) {
545 io_worker_handle_work(worker);
548 __io_worker_idle(wqe, worker);
549 raw_spin_unlock_irq(&wqe->lock);
550 if (io_flush_signals())
552 ret = schedule_timeout(WORKER_IDLE_TIMEOUT);
553 if (signal_pending(current)) {
556 if (!get_signal(&ksig))
562 /* timed out, exit unless we're the fixed worker */
563 if (!(worker->flags & IO_WORKER_F_FIXED))
567 if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
568 raw_spin_lock_irq(&wqe->lock);
569 io_worker_handle_work(worker);
572 io_worker_exit(worker);
577 * Called when a worker is scheduled in. Mark us as currently running.
579 void io_wq_worker_running(struct task_struct *tsk)
581 struct io_worker *worker = tsk->pf_io_worker;
585 if (!(worker->flags & IO_WORKER_F_UP))
587 if (worker->flags & IO_WORKER_F_RUNNING)
589 worker->flags |= IO_WORKER_F_RUNNING;
590 io_wqe_inc_running(worker);
594 * Called when worker is going to sleep. If there are no workers currently
595 * running and we have work pending, wake up a free one or create a new one.
597 void io_wq_worker_sleeping(struct task_struct *tsk)
599 struct io_worker *worker = tsk->pf_io_worker;
603 if (!(worker->flags & IO_WORKER_F_UP))
605 if (!(worker->flags & IO_WORKER_F_RUNNING))
608 worker->flags &= ~IO_WORKER_F_RUNNING;
610 raw_spin_lock_irq(&worker->wqe->lock);
611 io_wqe_dec_running(worker);
612 raw_spin_unlock_irq(&worker->wqe->lock);
615 static void create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
617 struct io_wqe_acct *acct = &wqe->acct[index];
618 struct io_worker *worker;
619 struct task_struct *tsk;
621 __set_current_state(TASK_RUNNING);
623 worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, wqe->node);
627 refcount_set(&worker->ref, 1);
628 worker->nulls_node.pprev = NULL;
630 spin_lock_init(&worker->lock);
631 init_completion(&worker->ref_done);
633 tsk = create_io_thread(io_wqe_worker, worker, wqe->node);
637 atomic_dec(&acct->nr_running);
638 io_worker_ref_put(wq);
642 tsk->pf_io_worker = worker;
644 set_cpus_allowed_ptr(tsk, wqe->cpu_mask);
645 tsk->flags |= PF_NO_SETAFFINITY;
647 raw_spin_lock_irq(&wqe->lock);
648 hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
649 list_add_tail_rcu(&worker->all_list, &wqe->all_list);
650 worker->flags |= IO_WORKER_F_FREE;
651 if (index == IO_WQ_ACCT_BOUND)
652 worker->flags |= IO_WORKER_F_BOUND;
653 if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND))
654 worker->flags |= IO_WORKER_F_FIXED;
656 raw_spin_unlock_irq(&wqe->lock);
657 wake_up_new_task(tsk);
661 * Iterate the passed in list and call the specific function for each
662 * worker that isn't exiting
664 static bool io_wq_for_each_worker(struct io_wqe *wqe,
665 bool (*func)(struct io_worker *, void *),
668 struct io_worker *worker;
671 list_for_each_entry_rcu(worker, &wqe->all_list, all_list) {
672 if (io_worker_get(worker)) {
673 /* no task if node is/was offline */
675 ret = func(worker, data);
676 io_worker_release(worker);
685 static bool io_wq_worker_wake(struct io_worker *worker, void *data)
687 set_notify_signal(worker->task);
688 wake_up_process(worker->task);
692 static bool io_wq_work_match_all(struct io_wq_work *work, void *data)
697 static void io_run_cancel(struct io_wq_work *work, struct io_wqe *wqe)
699 struct io_wq *wq = wqe->wq;
702 work->flags |= IO_WQ_WORK_CANCEL;
704 work = wq->free_work(work);
708 static void io_wqe_insert_work(struct io_wqe *wqe, struct io_wq_work *work)
711 struct io_wq_work *tail;
713 if (!io_wq_is_hashed(work)) {
715 wq_list_add_tail(&work->list, &wqe->work_list);
719 hash = io_get_work_hash(work);
720 tail = wqe->hash_tail[hash];
721 wqe->hash_tail[hash] = work;
725 wq_list_add_after(&work->list, &tail->list, &wqe->work_list);
728 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
730 struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
735 * If io-wq is exiting for this task, or if the request has explicitly
736 * been marked as one that should not get executed, cancel it here.
738 if (test_bit(IO_WQ_BIT_EXIT, &wqe->wq->state) ||
739 (work->flags & IO_WQ_WORK_CANCEL)) {
740 io_run_cancel(work, wqe);
744 work_flags = work->flags;
745 raw_spin_lock_irqsave(&wqe->lock, flags);
746 io_wqe_insert_work(wqe, work);
747 wqe->flags &= ~IO_WQE_FLAG_STALLED;
748 raw_spin_unlock_irqrestore(&wqe->lock, flags);
750 if ((work_flags & IO_WQ_WORK_CONCURRENT) ||
751 !atomic_read(&acct->nr_running))
752 io_wqe_wake_worker(wqe, acct);
755 void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
757 struct io_wqe *wqe = wq->wqes[numa_node_id()];
759 io_wqe_enqueue(wqe, work);
763 * Work items that hash to the same value will not be done in parallel.
764 * Used to limit concurrent writes, generally hashed by inode.
766 void io_wq_hash_work(struct io_wq_work *work, void *val)
770 bit = hash_ptr(val, IO_WQ_HASH_ORDER);
771 work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
774 static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
776 struct io_cb_cancel_data *match = data;
780 * Hold the lock to avoid ->cur_work going out of scope, caller
781 * may dereference the passed in work.
783 spin_lock_irqsave(&worker->lock, flags);
784 if (worker->cur_work &&
785 match->fn(worker->cur_work, match->data)) {
786 set_notify_signal(worker->task);
789 spin_unlock_irqrestore(&worker->lock, flags);
791 return match->nr_running && !match->cancel_all;
794 static inline void io_wqe_remove_pending(struct io_wqe *wqe,
795 struct io_wq_work *work,
796 struct io_wq_work_node *prev)
798 unsigned int hash = io_get_work_hash(work);
799 struct io_wq_work *prev_work = NULL;
801 if (io_wq_is_hashed(work) && work == wqe->hash_tail[hash]) {
803 prev_work = container_of(prev, struct io_wq_work, list);
804 if (prev_work && io_get_work_hash(prev_work) == hash)
805 wqe->hash_tail[hash] = prev_work;
807 wqe->hash_tail[hash] = NULL;
809 wq_list_del(&wqe->work_list, &work->list, prev);
812 static void io_wqe_cancel_pending_work(struct io_wqe *wqe,
813 struct io_cb_cancel_data *match)
815 struct io_wq_work_node *node, *prev;
816 struct io_wq_work *work;
820 raw_spin_lock_irqsave(&wqe->lock, flags);
821 wq_list_for_each(node, prev, &wqe->work_list) {
822 work = container_of(node, struct io_wq_work, list);
823 if (!match->fn(work, match->data))
825 io_wqe_remove_pending(wqe, work, prev);
826 raw_spin_unlock_irqrestore(&wqe->lock, flags);
827 io_run_cancel(work, wqe);
829 if (!match->cancel_all)
832 /* not safe to continue after unlock */
835 raw_spin_unlock_irqrestore(&wqe->lock, flags);
838 static void io_wqe_cancel_running_work(struct io_wqe *wqe,
839 struct io_cb_cancel_data *match)
842 io_wq_for_each_worker(wqe, io_wq_worker_cancel, match);
846 enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
847 void *data, bool cancel_all)
849 struct io_cb_cancel_data match = {
852 .cancel_all = cancel_all,
857 * First check pending list, if we're lucky we can just remove it
858 * from there. CANCEL_OK means that the work is returned as-new,
859 * no completion will be posted for it.
861 for_each_node(node) {
862 struct io_wqe *wqe = wq->wqes[node];
864 io_wqe_cancel_pending_work(wqe, &match);
865 if (match.nr_pending && !match.cancel_all)
866 return IO_WQ_CANCEL_OK;
870 * Now check if a free (going busy) or busy worker has the work
871 * currently running. If we find it there, we'll return CANCEL_RUNNING
872 * as an indication that we attempt to signal cancellation. The
873 * completion will run normally in this case.
875 for_each_node(node) {
876 struct io_wqe *wqe = wq->wqes[node];
878 io_wqe_cancel_running_work(wqe, &match);
879 if (match.nr_running && !match.cancel_all)
880 return IO_WQ_CANCEL_RUNNING;
883 if (match.nr_running)
884 return IO_WQ_CANCEL_RUNNING;
885 if (match.nr_pending)
886 return IO_WQ_CANCEL_OK;
887 return IO_WQ_CANCEL_NOTFOUND;
890 static int io_wqe_hash_wake(struct wait_queue_entry *wait, unsigned mode,
893 struct io_wqe *wqe = container_of(wait, struct io_wqe, wait);
895 list_del_init(&wait->entry);
898 io_wqe_activate_free_worker(wqe);
903 struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
908 if (WARN_ON_ONCE(!data->free_work || !data->do_work))
909 return ERR_PTR(-EINVAL);
910 if (WARN_ON_ONCE(!bounded))
911 return ERR_PTR(-EINVAL);
913 wq = kzalloc(struct_size(wq, wqes, nr_node_ids), GFP_KERNEL);
915 return ERR_PTR(-ENOMEM);
916 ret = cpuhp_state_add_instance_nocalls(io_wq_online, &wq->cpuhp_node);
920 refcount_inc(&data->hash->refs);
921 wq->hash = data->hash;
922 wq->free_work = data->free_work;
923 wq->do_work = data->do_work;
926 for_each_node(node) {
928 int alloc_node = node;
930 if (!node_online(alloc_node))
931 alloc_node = NUMA_NO_NODE;
932 wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node);
935 if (!alloc_cpumask_var(&wqe->cpu_mask, GFP_KERNEL))
937 cpumask_copy(wqe->cpu_mask, cpumask_of_node(node));
938 wq->wqes[node] = wqe;
939 wqe->node = alloc_node;
940 wqe->acct[IO_WQ_ACCT_BOUND].index = IO_WQ_ACCT_BOUND;
941 wqe->acct[IO_WQ_ACCT_UNBOUND].index = IO_WQ_ACCT_UNBOUND;
942 wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
943 atomic_set(&wqe->acct[IO_WQ_ACCT_BOUND].nr_running, 0);
944 wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
945 task_rlimit(current, RLIMIT_NPROC);
946 atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0);
947 wqe->wait.func = io_wqe_hash_wake;
948 INIT_LIST_HEAD(&wqe->wait.entry);
950 raw_spin_lock_init(&wqe->lock);
951 INIT_WQ_LIST(&wqe->work_list);
952 INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0);
953 INIT_LIST_HEAD(&wqe->all_list);
956 wq->task = get_task_struct(data->task);
957 atomic_set(&wq->worker_refs, 1);
958 init_completion(&wq->worker_done);
961 io_wq_put_hash(data->hash);
962 cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node);
963 for_each_node(node) {
966 free_cpumask_var(wq->wqes[node]->cpu_mask);
967 kfree(wq->wqes[node]);
974 static bool io_task_work_match(struct callback_head *cb, void *data)
976 struct create_worker_data *cwd;
978 if (cb->func != create_worker_cb)
980 cwd = container_of(cb, struct create_worker_data, work);
981 return cwd->wqe->wq == data;
984 void io_wq_exit_start(struct io_wq *wq)
986 set_bit(IO_WQ_BIT_EXIT, &wq->state);
989 static void io_wq_exit_workers(struct io_wq *wq)
991 struct callback_head *cb;
997 while ((cb = task_work_cancel_match(wq->task, io_task_work_match, wq)) != NULL) {
998 struct create_worker_data *cwd;
1000 cwd = container_of(cb, struct create_worker_data, work);
1001 atomic_dec(&cwd->wqe->acct[cwd->index].nr_running);
1002 io_worker_ref_put(wq);
1007 for_each_node(node) {
1008 struct io_wqe *wqe = wq->wqes[node];
1010 io_wq_for_each_worker(wqe, io_wq_worker_wake, NULL);
1013 io_worker_ref_put(wq);
1014 wait_for_completion(&wq->worker_done);
1016 for_each_node(node) {
1017 spin_lock_irq(&wq->hash->wait.lock);
1018 list_del_init(&wq->wqes[node]->wait.entry);
1019 spin_unlock_irq(&wq->hash->wait.lock);
1021 put_task_struct(wq->task);
1025 static void io_wq_destroy(struct io_wq *wq)
1029 cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node);
1031 for_each_node(node) {
1032 struct io_wqe *wqe = wq->wqes[node];
1033 struct io_cb_cancel_data match = {
1034 .fn = io_wq_work_match_all,
1037 io_wqe_cancel_pending_work(wqe, &match);
1038 free_cpumask_var(wqe->cpu_mask);
1041 io_wq_put_hash(wq->hash);
1045 void io_wq_put_and_exit(struct io_wq *wq)
1047 WARN_ON_ONCE(!test_bit(IO_WQ_BIT_EXIT, &wq->state));
1049 io_wq_exit_workers(wq);
1053 struct online_data {
1058 static bool io_wq_worker_affinity(struct io_worker *worker, void *data)
1060 struct online_data *od = data;
1063 cpumask_set_cpu(od->cpu, worker->wqe->cpu_mask);
1065 cpumask_clear_cpu(od->cpu, worker->wqe->cpu_mask);
1069 static int __io_wq_cpu_online(struct io_wq *wq, unsigned int cpu, bool online)
1071 struct online_data od = {
1079 io_wq_for_each_worker(wq->wqes[i], io_wq_worker_affinity, &od);
1084 static int io_wq_cpu_online(unsigned int cpu, struct hlist_node *node)
1086 struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node);
1088 return __io_wq_cpu_online(wq, cpu, true);
1091 static int io_wq_cpu_offline(unsigned int cpu, struct hlist_node *node)
1093 struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node);
1095 return __io_wq_cpu_online(wq, cpu, false);
1098 int io_wq_cpu_affinity(struct io_wq *wq, cpumask_var_t mask)
1104 struct io_wqe *wqe = wq->wqes[i];
1107 cpumask_copy(wqe->cpu_mask, mask);
1109 cpumask_copy(wqe->cpu_mask, cpumask_of_node(i));
1115 static __init int io_wq_init(void)
1119 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "io-wq/online",
1120 io_wq_cpu_online, io_wq_cpu_offline);
1126 subsys_initcall(io_wq_init);