| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Jens Axboe | 4459 | 73.04% | 79 | 56.43% |
| Pavel Begunkov | 915 | 14.99% | 30 | 21.43% |
| Hao Xu | 249 | 4.08% | 9 | 6.43% |
| Gabriel Krisman Bertazi | 218 | 3.57% | 2 | 1.43% |
| Hillf Danton | 88 | 1.44% | 1 | 0.71% |
| Eugene Syromiatnikov | 39 | 0.64% | 1 | 0.71% |
| Beld Zhang | 29 | 0.48% | 1 | 0.71% |
| Dennis Zhou | 26 | 0.43% | 1 | 0.71% |
| Breno Leitão | 25 | 0.41% | 1 | 0.71% |
| Zhang Qiang | 15 | 0.25% | 1 | 0.71% |
| Jeff Moyer | 10 | 0.16% | 1 | 0.71% |
| Taehee Yoo | 6 | 0.10% | 1 | 0.71% |
| Simon Horman | 5 | 0.08% | 1 | 0.71% |
| Eric W. Biedermann | 4 | 0.07% | 2 | 1.43% |
| Paul Turner | 4 | 0.07% | 1 | 0.71% |
| Andrew Morton | 3 | 0.05% | 1 | 0.71% |
| Peter Zijlstra | 3 | 0.05% | 3 | 2.14% |
| Sebastian Andrzej Siewior | 2 | 0.03% | 1 | 0.71% |
| Yue haibing | 2 | 0.03% | 1 | 0.71% |
| yangerkun | 2 | 0.03% | 1 | 0.71% |
| Jann Horn | 1 | 0.02% | 1 | 0.71% |
| Total | 6105 | 140 |
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// SPDX-License-Identifier: GPL-2.0 /* * Basic worker thread pool for io_uring * * Copyright (C) 2019 Jens Axboe * */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/errno.h> #include <linux/sched/signal.h> #include <linux/percpu.h> #include <linux/slab.h> #include <linux/rculist_nulls.h> #include <linux/cpu.h> #include <linux/task_work.h> #include <linux/audit.h> #include <linux/mmu_context.h> #include <uapi/linux/io_uring.h> #include "io-wq.h" #include "slist.h" #include "io_uring.h" #define WORKER_IDLE_TIMEOUT (5 * HZ) enum { IO_WORKER_F_UP = 1, /* up and active */ IO_WORKER_F_RUNNING = 2, /* account as running */ IO_WORKER_F_FREE = 4, /* worker on free list */ IO_WORKER_F_BOUND = 8, /* is doing bounded work */ }; enum { IO_WQ_BIT_EXIT = 0, /* wq exiting */ }; enum { IO_ACCT_STALLED_BIT = 0, /* stalled on hash */ }; /* * One for each thread in a wq pool */ struct io_worker { refcount_t ref; unsigned flags; struct hlist_nulls_node nulls_node; struct list_head all_list; struct task_struct *task; struct io_wq *wq; struct io_wq_work *cur_work; struct io_wq_work *next_work; raw_spinlock_t lock; struct completion ref_done; unsigned long create_state; struct callback_head create_work; int create_index; union { struct rcu_head rcu; struct work_struct work; }; }; #if BITS_PER_LONG == 64 #define IO_WQ_HASH_ORDER 6 #else #define IO_WQ_HASH_ORDER 5 #endif #define IO_WQ_NR_HASH_BUCKETS (1u << IO_WQ_HASH_ORDER) struct io_wq_acct { unsigned nr_workers; unsigned max_workers; int index; atomic_t nr_running; raw_spinlock_t lock; struct io_wq_work_list work_list; unsigned long flags; }; enum { IO_WQ_ACCT_BOUND, IO_WQ_ACCT_UNBOUND, IO_WQ_ACCT_NR, }; /* * Per io_wq state */ struct io_wq { unsigned long state; free_work_fn *free_work; io_wq_work_fn *do_work; struct io_wq_hash *hash; atomic_t worker_refs; struct completion worker_done; struct hlist_node cpuhp_node; struct task_struct *task; struct io_wq_acct acct[IO_WQ_ACCT_NR]; /* lock protects access to elements below */ raw_spinlock_t lock; struct hlist_nulls_head free_list; struct list_head all_list; struct wait_queue_entry wait; struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS]; cpumask_var_t cpu_mask; }; static enum cpuhp_state io_wq_online; struct io_cb_cancel_data { work_cancel_fn *fn; void *data; int nr_running; int nr_pending; bool cancel_all; }; static bool create_io_worker(struct io_wq *wq, int index); static void io_wq_dec_running(struct io_worker *worker); static bool io_acct_cancel_pending_work(struct io_wq *wq, struct io_wq_acct *acct, struct io_cb_cancel_data *match); static void create_worker_cb(struct callback_head *cb); static void io_wq_cancel_tw_create(struct io_wq *wq); static bool io_worker_get(struct io_worker *worker) { return refcount_inc_not_zero(&worker->ref); } static void io_worker_release(struct io_worker *worker) { if (refcount_dec_and_test(&worker->ref)) complete(&worker->ref_done); } static inline struct io_wq_acct *io_get_acct(struct io_wq *wq, bool bound) { return &wq->acct[bound ? IO_WQ_ACCT_BOUND : IO_WQ_ACCT_UNBOUND]; } static inline struct io_wq_acct *io_work_get_acct(struct io_wq *wq, struct io_wq_work *work) { return io_get_acct(wq, !(work->flags & IO_WQ_WORK_UNBOUND)); } static inline struct io_wq_acct *io_wq_get_acct(struct io_worker *worker) { return io_get_acct(worker->wq, worker->flags & IO_WORKER_F_BOUND); } static void io_worker_ref_put(struct io_wq *wq) { if (atomic_dec_and_test(&wq->worker_refs)) complete(&wq->worker_done); } bool io_wq_worker_stopped(void) { struct io_worker *worker = current->worker_private; if (WARN_ON_ONCE(!io_wq_current_is_worker())) return true; return test_bit(IO_WQ_BIT_EXIT, &worker->wq->state); } static void io_worker_cancel_cb(struct io_worker *worker) { struct io_wq_acct *acct = io_wq_get_acct(worker); struct io_wq *wq = worker->wq; atomic_dec(&acct->nr_running); raw_spin_lock(&wq->lock); acct->nr_workers--; raw_spin_unlock(&wq->lock); io_worker_ref_put(wq); clear_bit_unlock(0, &worker->create_state); io_worker_release(worker); } static bool io_task_worker_match(struct callback_head *cb, void *data) { struct io_worker *worker; if (cb->func != create_worker_cb) return false; worker = container_of(cb, struct io_worker, create_work); return worker == data; } static void io_worker_exit(struct io_worker *worker) { struct io_wq *wq = worker->wq; while (1) { struct callback_head *cb = task_work_cancel_match(wq->task, io_task_worker_match, worker); if (!cb) break; io_worker_cancel_cb(worker); } io_worker_release(worker); wait_for_completion(&worker->ref_done); raw_spin_lock(&wq->lock); if (worker->flags & IO_WORKER_F_FREE) hlist_nulls_del_rcu(&worker->nulls_node); list_del_rcu(&worker->all_list); raw_spin_unlock(&wq->lock); io_wq_dec_running(worker); /* * this worker is a goner, clear ->worker_private to avoid any * inc/dec running calls that could happen as part of exit from * touching 'worker'. */ current->worker_private = NULL; kfree_rcu(worker, rcu); io_worker_ref_put(wq); do_exit(0); } static inline bool __io_acct_run_queue(struct io_wq_acct *acct) { return !test_bit(IO_ACCT_STALLED_BIT, &acct->flags) && !wq_list_empty(&acct->work_list); } /* * If there's work to do, returns true with acct->lock acquired. If not, * returns false with no lock held. */ static inline bool io_acct_run_queue(struct io_wq_acct *acct) __acquires(&acct->lock) { raw_spin_lock(&acct->lock); if (__io_acct_run_queue(acct)) return true; raw_spin_unlock(&acct->lock); return false; } /* * Check head of free list for an available worker. If one isn't available, * caller must create one. */ static bool io_wq_activate_free_worker(struct io_wq *wq, struct io_wq_acct *acct) __must_hold(RCU) { struct hlist_nulls_node *n; struct io_worker *worker; /* * Iterate free_list and see if we can find an idle worker to * activate. If a given worker is on the free_list but in the process * of exiting, keep trying. */ hlist_nulls_for_each_entry_rcu(worker, n, &wq->free_list, nulls_node) { if (!io_worker_get(worker)) continue; if (io_wq_get_acct(worker) != acct) { io_worker_release(worker); continue; } /* * If the worker is already running, it's either already * starting work or finishing work. In either case, if it does * to go sleep, we'll kick off a new task for this work anyway. */ wake_up_process(worker->task); io_worker_release(worker); return true; } return false; } /* * We need a worker. If we find a free one, we're good. If not, and we're * below the max number of workers, create one. */ static bool io_wq_create_worker(struct io_wq *wq, struct io_wq_acct *acct) { /* * Most likely an attempt to queue unbounded work on an io_wq that * wasn't setup with any unbounded workers. */ if (unlikely(!acct->max_workers)) pr_warn_once("io-wq is not configured for unbound workers"); raw_spin_lock(&wq->lock); if (acct->nr_workers >= acct->max_workers) { raw_spin_unlock(&wq->lock); return true; } acct->nr_workers++; raw_spin_unlock(&wq->lock); atomic_inc(&acct->nr_running); atomic_inc(&wq->worker_refs); return create_io_worker(wq, acct->index); } static void io_wq_inc_running(struct io_worker *worker) { struct io_wq_acct *acct = io_wq_get_acct(worker); atomic_inc(&acct->nr_running); } static void create_worker_cb(struct callback_head *cb) { struct io_worker *worker; struct io_wq *wq; struct io_wq_acct *acct; bool do_create = false; worker = container_of(cb, struct io_worker, create_work); wq = worker->wq; acct = &wq->acct[worker->create_index]; raw_spin_lock(&wq->lock); if (acct->nr_workers < acct->max_workers) { acct->nr_workers++; do_create = true; } raw_spin_unlock(&wq->lock); if (do_create) { create_io_worker(wq, worker->create_index); } else { atomic_dec(&acct->nr_running); io_worker_ref_put(wq); } clear_bit_unlock(0, &worker->create_state); io_worker_release(worker); } static bool io_queue_worker_create(struct io_worker *worker, struct io_wq_acct *acct, task_work_func_t func) { struct io_wq *wq = worker->wq; /* raced with exit, just ignore create call */ if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) goto fail; if (!io_worker_get(worker)) goto fail; /* * create_state manages ownership of create_work/index. We should * only need one entry per worker, as the worker going to sleep * will trigger the condition, and waking will clear it once it * runs the task_work. */ if (test_bit(0, &worker->create_state) || test_and_set_bit_lock(0, &worker->create_state)) goto fail_release; atomic_inc(&wq->worker_refs); init_task_work(&worker->create_work, func); worker->create_index = acct->index; if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL)) { /* * EXIT may have been set after checking it above, check after * adding the task_work and remove any creation item if it is * now set. wq exit does that too, but we can have added this * work item after we canceled in io_wq_exit_workers(). */ if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) io_wq_cancel_tw_create(wq); io_worker_ref_put(wq); return true; } io_worker_ref_put(wq); clear_bit_unlock(0, &worker->create_state); fail_release: io_worker_release(worker); fail: atomic_dec(&acct->nr_running); io_worker_ref_put(wq); return false; } static void io_wq_dec_running(struct io_worker *worker) { struct io_wq_acct *acct = io_wq_get_acct(worker); struct io_wq *wq = worker->wq; if (!(worker->flags & IO_WORKER_F_UP)) return; if (!atomic_dec_and_test(&acct->nr_running)) return; if (!io_acct_run_queue(acct)) return; raw_spin_unlock(&acct->lock); atomic_inc(&acct->nr_running); atomic_inc(&wq->worker_refs); io_queue_worker_create(worker, acct, create_worker_cb); } /* * Worker will start processing some work. Move it to the busy list, if * it's currently on the freelist */ static void __io_worker_busy(struct io_wq *wq, struct io_worker *worker) { if (worker->flags & IO_WORKER_F_FREE) { worker->flags &= ~IO_WORKER_F_FREE; raw_spin_lock(&wq->lock); hlist_nulls_del_init_rcu(&worker->nulls_node); raw_spin_unlock(&wq->lock); } } /* * No work, worker going to sleep. Move to freelist. */ static void __io_worker_idle(struct io_wq *wq, struct io_worker *worker) __must_hold(wq->lock) { if (!(worker->flags & IO_WORKER_F_FREE)) { worker->flags |= IO_WORKER_F_FREE; hlist_nulls_add_head_rcu(&worker->nulls_node, &wq->free_list); } } static inline unsigned int io_get_work_hash(struct io_wq_work *work) { return work->flags >> IO_WQ_HASH_SHIFT; } static bool io_wait_on_hash(struct io_wq *wq, unsigned int hash) { bool ret = false; spin_lock_irq(&wq->hash->wait.lock); if (list_empty(&wq->wait.entry)) { __add_wait_queue(&wq->hash->wait, &wq->wait); if (!test_bit(hash, &wq->hash->map)) { __set_current_state(TASK_RUNNING); list_del_init(&wq->wait.entry); ret = true; } } spin_unlock_irq(&wq->hash->wait.lock); return ret; } static struct io_wq_work *io_get_next_work(struct io_wq_acct *acct, struct io_worker *worker) __must_hold(acct->lock) { struct io_wq_work_node *node, *prev; struct io_wq_work *work, *tail; unsigned int stall_hash = -1U; struct io_wq *wq = worker->wq; wq_list_for_each(node, prev, &acct->work_list) { unsigned int hash; work = container_of(node, struct io_wq_work, list); /* not hashed, can run anytime */ if (!io_wq_is_hashed(work)) { wq_list_del(&acct->work_list, node, prev); return work; } hash = io_get_work_hash(work); /* all items with this hash lie in [work, tail] */ tail = wq->hash_tail[hash]; /* hashed, can run if not already running */ if (!test_and_set_bit(hash, &wq->hash->map)) { wq->hash_tail[hash] = NULL; wq_list_cut(&acct->work_list, &tail->list, prev); return work; } if (stall_hash == -1U) stall_hash = hash; /* fast forward to a next hash, for-each will fix up @prev */ node = &tail->list; } if (stall_hash != -1U) { bool unstalled; /* * Set this before dropping the lock to avoid racing with new * work being added and clearing the stalled bit. */ set_bit(IO_ACCT_STALLED_BIT, &acct->flags); raw_spin_unlock(&acct->lock); unstalled = io_wait_on_hash(wq, stall_hash); raw_spin_lock(&acct->lock); if (unstalled) { clear_bit(IO_ACCT_STALLED_BIT, &acct->flags); if (wq_has_sleeper(&wq->hash->wait)) wake_up(&wq->hash->wait); } } return NULL; } static void io_assign_current_work(struct io_worker *worker, struct io_wq_work *work) { if (work) { io_run_task_work(); cond_resched(); } raw_spin_lock(&worker->lock); worker->cur_work = work; worker->next_work = NULL; raw_spin_unlock(&worker->lock); } /* * Called with acct->lock held, drops it before returning */ static void io_worker_handle_work(struct io_wq_acct *acct, struct io_worker *worker) __releases(&acct->lock) { struct io_wq *wq = worker->wq; bool do_kill = test_bit(IO_WQ_BIT_EXIT, &wq->state); do { struct io_wq_work *work; /* * If we got some work, mark us as busy. If we didn't, but * the list isn't empty, it means we stalled on hashed work. * Mark us stalled so we don't keep looking for work when we * can't make progress, any work completion or insertion will * clear the stalled flag. */ work = io_get_next_work(acct, worker); raw_spin_unlock(&acct->lock); if (work) { __io_worker_busy(wq, worker); /* * Make sure cancelation can find this, even before * it becomes the active work. That avoids a window * where the work has been removed from our general * work list, but isn't yet discoverable as the * current work item for this worker. */ raw_spin_lock(&worker->lock); worker->next_work = work; raw_spin_unlock(&worker->lock); } else { break; } io_assign_current_work(worker, work); __set_current_state(TASK_RUNNING); /* handle a whole dependent link */ do { struct io_wq_work *next_hashed, *linked; unsigned int hash = io_get_work_hash(work); next_hashed = wq_next_work(work); if (unlikely(do_kill) && (work->flags & IO_WQ_WORK_UNBOUND)) work->flags |= IO_WQ_WORK_CANCEL; wq->do_work(work); io_assign_current_work(worker, NULL); linked = wq->free_work(work); work = next_hashed; if (!work && linked && !io_wq_is_hashed(linked)) { work = linked; linked = NULL; } io_assign_current_work(worker, work); if (linked) io_wq_enqueue(wq, linked); if (hash != -1U && !next_hashed) { /* serialize hash clear with wake_up() */ spin_lock_irq(&wq->hash->wait.lock); clear_bit(hash, &wq->hash->map); clear_bit(IO_ACCT_STALLED_BIT, &acct->flags); spin_unlock_irq(&wq->hash->wait.lock); if (wq_has_sleeper(&wq->hash->wait)) wake_up(&wq->hash->wait); } } while (work); if (!__io_acct_run_queue(acct)) break; raw_spin_lock(&acct->lock); } while (1); } static int io_wq_worker(void *data) { struct io_worker *worker = data; struct io_wq_acct *acct = io_wq_get_acct(worker); struct io_wq *wq = worker->wq; bool exit_mask = false, last_timeout = false; char buf[TASK_COMM_LEN]; worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING); snprintf(buf, sizeof(buf), "iou-wrk-%d", wq->task->pid); set_task_comm(current, buf); while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) { long ret; set_current_state(TASK_INTERRUPTIBLE); /* * If we have work to do, io_acct_run_queue() returns with * the acct->lock held. If not, it will drop it. */ while (io_acct_run_queue(acct)) io_worker_handle_work(acct, worker); raw_spin_lock(&wq->lock); /* * Last sleep timed out. Exit if we're not the last worker, * or if someone modified our affinity. */ if (last_timeout && (exit_mask || acct->nr_workers > 1)) { acct->nr_workers--; raw_spin_unlock(&wq->lock); __set_current_state(TASK_RUNNING); break; } last_timeout = false; __io_worker_idle(wq, worker); raw_spin_unlock(&wq->lock); if (io_run_task_work()) continue; ret = schedule_timeout(WORKER_IDLE_TIMEOUT); if (signal_pending(current)) { struct ksignal ksig; if (!get_signal(&ksig)) continue; break; } if (!ret) { last_timeout = true; exit_mask = !cpumask_test_cpu(raw_smp_processor_id(), wq->cpu_mask); } } if (test_bit(IO_WQ_BIT_EXIT, &wq->state) && io_acct_run_queue(acct)) io_worker_handle_work(acct, worker); io_worker_exit(worker); return 0; } /* * Called when a worker is scheduled in. Mark us as currently running. */ void io_wq_worker_running(struct task_struct *tsk) { struct io_worker *worker = tsk->worker_private; if (!worker) return; if (!(worker->flags & IO_WORKER_F_UP)) return; if (worker->flags & IO_WORKER_F_RUNNING) return; worker->flags |= IO_WORKER_F_RUNNING; io_wq_inc_running(worker); } /* * Called when worker is going to sleep. If there are no workers currently * running and we have work pending, wake up a free one or create a new one. */ void io_wq_worker_sleeping(struct task_struct *tsk) { struct io_worker *worker = tsk->worker_private; if (!worker) return; if (!(worker->flags & IO_WORKER_F_UP)) return; if (!(worker->flags & IO_WORKER_F_RUNNING)) return; worker->flags &= ~IO_WORKER_F_RUNNING; io_wq_dec_running(worker); } static void io_init_new_worker(struct io_wq *wq, struct io_worker *worker, struct task_struct *tsk) { tsk->worker_private = worker; worker->task = tsk; set_cpus_allowed_ptr(tsk, wq->cpu_mask); raw_spin_lock(&wq->lock); hlist_nulls_add_head_rcu(&worker->nulls_node, &wq->free_list); list_add_tail_rcu(&worker->all_list, &wq->all_list); worker->flags |= IO_WORKER_F_FREE; raw_spin_unlock(&wq->lock); wake_up_new_task(tsk); } static bool io_wq_work_match_all(struct io_wq_work *work, void *data) { return true; } static inline bool io_should_retry_thread(long err) { /* * Prevent perpetual task_work retry, if the task (or its group) is * exiting. */ if (fatal_signal_pending(current)) return false; switch (err) { case -EAGAIN: case -ERESTARTSYS: case -ERESTARTNOINTR: case -ERESTARTNOHAND: return true; default: return false; } } static void create_worker_cont(struct callback_head *cb) { struct io_worker *worker; struct task_struct *tsk; struct io_wq *wq; worker = container_of(cb, struct io_worker, create_work); clear_bit_unlock(0, &worker->create_state); wq = worker->wq; tsk = create_io_thread(io_wq_worker, worker, NUMA_NO_NODE); if (!IS_ERR(tsk)) { io_init_new_worker(wq, worker, tsk); io_worker_release(worker); return; } else if (!io_should_retry_thread(PTR_ERR(tsk))) { struct io_wq_acct *acct = io_wq_get_acct(worker); atomic_dec(&acct->nr_running); raw_spin_lock(&wq->lock); acct->nr_workers--; if (!acct->nr_workers) { struct io_cb_cancel_data match = { .fn = io_wq_work_match_all, .cancel_all = true, }; raw_spin_unlock(&wq->lock); while (io_acct_cancel_pending_work(wq, acct, &match)) ; } else { raw_spin_unlock(&wq->lock); } io_worker_ref_put(wq); kfree(worker); return; } /* re-create attempts grab a new worker ref, drop the existing one */ io_worker_release(worker); schedule_work(&worker->work); } static void io_workqueue_create(struct work_struct *work) { struct io_worker *worker = container_of(work, struct io_worker, work); struct io_wq_acct *acct = io_wq_get_acct(worker); if (!io_queue_worker_create(worker, acct, create_worker_cont)) kfree(worker); } static bool create_io_worker(struct io_wq *wq, int index) { struct io_wq_acct *acct = &wq->acct[index]; struct io_worker *worker; struct task_struct *tsk; __set_current_state(TASK_RUNNING); worker = kzalloc(sizeof(*worker), GFP_KERNEL); if (!worker) { fail: atomic_dec(&acct->nr_running); raw_spin_lock(&wq->lock); acct->nr_workers--; raw_spin_unlock(&wq->lock); io_worker_ref_put(wq); return false; } refcount_set(&worker->ref, 1); worker->wq = wq; raw_spin_lock_init(&worker->lock); init_completion(&worker->ref_done); if (index == IO_WQ_ACCT_BOUND) worker->flags |= IO_WORKER_F_BOUND; tsk = create_io_thread(io_wq_worker, worker, NUMA_NO_NODE); if (!IS_ERR(tsk)) { io_init_new_worker(wq, worker, tsk); } else if (!io_should_retry_thread(PTR_ERR(tsk))) { kfree(worker); goto fail; } else { INIT_WORK(&worker->work, io_workqueue_create); schedule_work(&worker->work); } return true; } /* * Iterate the passed in list and call the specific function for each * worker that isn't exiting */ static bool io_wq_for_each_worker(struct io_wq *wq, bool (*func)(struct io_worker *, void *), void *data) { struct io_worker *worker; bool ret = false; list_for_each_entry_rcu(worker, &wq->all_list, all_list) { if (io_worker_get(worker)) { /* no task if node is/was offline */ if (worker->task) ret = func(worker, data); io_worker_release(worker); if (ret) break; } } return ret; } static bool io_wq_worker_wake(struct io_worker *worker, void *data) { __set_notify_signal(worker->task); wake_up_process(worker->task); return false; } static void io_run_cancel(struct io_wq_work *work, struct io_wq *wq) { do { work->flags |= IO_WQ_WORK_CANCEL; wq->do_work(work); work = wq->free_work(work); } while (work); } static void io_wq_insert_work(struct io_wq *wq, struct io_wq_work *work) { struct io_wq_acct *acct = io_work_get_acct(wq, work); unsigned int hash; struct io_wq_work *tail; if (!io_wq_is_hashed(work)) { append: wq_list_add_tail(&work->list, &acct->work_list); return; } hash = io_get_work_hash(work); tail = wq->hash_tail[hash]; wq->hash_tail[hash] = work; if (!tail) goto append; wq_list_add_after(&work->list, &tail->list, &acct->work_list); } static bool io_wq_work_match_item(struct io_wq_work *work, void *data) { return work == data; } void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work) { struct io_wq_acct *acct = io_work_get_acct(wq, work); struct io_cb_cancel_data match; unsigned work_flags = work->flags; bool do_create; /* * If io-wq is exiting for this task, or if the request has explicitly * been marked as one that should not get executed, cancel it here. */ if (test_bit(IO_WQ_BIT_EXIT, &wq->state) || (work->flags & IO_WQ_WORK_CANCEL)) { io_run_cancel(work, wq); return; } raw_spin_lock(&acct->lock); io_wq_insert_work(wq, work); clear_bit(IO_ACCT_STALLED_BIT, &acct->flags); raw_spin_unlock(&acct->lock); rcu_read_lock(); do_create = !io_wq_activate_free_worker(wq, acct); rcu_read_unlock(); if (do_create && ((work_flags & IO_WQ_WORK_CONCURRENT) || !atomic_read(&acct->nr_running))) { bool did_create; did_create = io_wq_create_worker(wq, acct); if (likely(did_create)) return; raw_spin_lock(&wq->lock); if (acct->nr_workers) { raw_spin_unlock(&wq->lock); return; } raw_spin_unlock(&wq->lock); /* fatal condition, failed to create the first worker */ match.fn = io_wq_work_match_item, match.data = work, match.cancel_all = false, io_acct_cancel_pending_work(wq, acct, &match); } } /* * Work items that hash to the same value will not be done in parallel. * Used to limit concurrent writes, generally hashed by inode. */ void io_wq_hash_work(struct io_wq_work *work, void *val) { unsigned int bit; bit = hash_ptr(val, IO_WQ_HASH_ORDER); work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT)); } static bool __io_wq_worker_cancel(struct io_worker *worker, struct io_cb_cancel_data *match, struct io_wq_work *work) { if (work && match->fn(work, match->data)) { work->flags |= IO_WQ_WORK_CANCEL; __set_notify_signal(worker->task); return true; } return false; } static bool io_wq_worker_cancel(struct io_worker *worker, void *data) { struct io_cb_cancel_data *match = data; /* * Hold the lock to avoid ->cur_work going out of scope, caller * may dereference the passed in work. */ raw_spin_lock(&worker->lock); if (__io_wq_worker_cancel(worker, match, worker->cur_work) || __io_wq_worker_cancel(worker, match, worker->next_work)) match->nr_running++; raw_spin_unlock(&worker->lock); return match->nr_running && !match->cancel_all; } static inline void io_wq_remove_pending(struct io_wq *wq, struct io_wq_work *work, struct io_wq_work_node *prev) { struct io_wq_acct *acct = io_work_get_acct(wq, work); unsigned int hash = io_get_work_hash(work); struct io_wq_work *prev_work = NULL; if (io_wq_is_hashed(work) && work == wq->hash_tail[hash]) { if (prev) prev_work = container_of(prev, struct io_wq_work, list); if (prev_work && io_get_work_hash(prev_work) == hash) wq->hash_tail[hash] = prev_work; else wq->hash_tail[hash] = NULL; } wq_list_del(&acct->work_list, &work->list, prev); } static bool io_acct_cancel_pending_work(struct io_wq *wq, struct io_wq_acct *acct, struct io_cb_cancel_data *match) { struct io_wq_work_node *node, *prev; struct io_wq_work *work; raw_spin_lock(&acct->lock); wq_list_for_each(node, prev, &acct->work_list) { work = container_of(node, struct io_wq_work, list); if (!match->fn(work, match->data)) continue; io_wq_remove_pending(wq, work, prev); raw_spin_unlock(&acct->lock); io_run_cancel(work, wq); match->nr_pending++; /* not safe to continue after unlock */ return true; } raw_spin_unlock(&acct->lock); return false; } static void io_wq_cancel_pending_work(struct io_wq *wq, struct io_cb_cancel_data *match) { int i; retry: for (i = 0; i < IO_WQ_ACCT_NR; i++) { struct io_wq_acct *acct = io_get_acct(wq, i == 0); if (io_acct_cancel_pending_work(wq, acct, match)) { if (match->cancel_all) goto retry; break; } } } static void io_wq_cancel_running_work(struct io_wq *wq, struct io_cb_cancel_data *match) { rcu_read_lock(); io_wq_for_each_worker(wq, io_wq_worker_cancel, match); rcu_read_unlock(); } enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel, void *data, bool cancel_all) { struct io_cb_cancel_data match = { .fn = cancel, .data = data, .cancel_all = cancel_all, }; /* * First check pending list, if we're lucky we can just remove it * from there. CANCEL_OK means that the work is returned as-new, * no completion will be posted for it. * * Then check if a free (going busy) or busy worker has the work * currently running. If we find it there, we'll return CANCEL_RUNNING * as an indication that we attempt to signal cancellation. The * completion will run normally in this case. * * Do both of these while holding the wq->lock, to ensure that * we'll find a work item regardless of state. */ io_wq_cancel_pending_work(wq, &match); if (match.nr_pending && !match.cancel_all) return IO_WQ_CANCEL_OK; raw_spin_lock(&wq->lock); io_wq_cancel_running_work(wq, &match); raw_spin_unlock(&wq->lock); if (match.nr_running && !match.cancel_all) return IO_WQ_CANCEL_RUNNING; if (match.nr_running) return IO_WQ_CANCEL_RUNNING; if (match.nr_pending) return IO_WQ_CANCEL_OK; return IO_WQ_CANCEL_NOTFOUND; } static int io_wq_hash_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct io_wq *wq = container_of(wait, struct io_wq, wait); int i; list_del_init(&wait->entry); rcu_read_lock(); for (i = 0; i < IO_WQ_ACCT_NR; i++) { struct io_wq_acct *acct = &wq->acct[i]; if (test_and_clear_bit(IO_ACCT_STALLED_BIT, &acct->flags)) io_wq_activate_free_worker(wq, acct); } rcu_read_unlock(); return 1; } struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data) { int ret, i; struct io_wq *wq; if (WARN_ON_ONCE(!data->free_work || !data->do_work)) return ERR_PTR(-EINVAL); if (WARN_ON_ONCE(!bounded)) return ERR_PTR(-EINVAL); wq = kzalloc(sizeof(struct io_wq), GFP_KERNEL); if (!wq) return ERR_PTR(-ENOMEM); refcount_inc(&data->hash->refs); wq->hash = data->hash; wq->free_work = data->free_work; wq->do_work = data->do_work; ret = -ENOMEM; if (!alloc_cpumask_var(&wq->cpu_mask, GFP_KERNEL)) goto err; cpumask_copy(wq->cpu_mask, cpu_possible_mask); wq->acct[IO_WQ_ACCT_BOUND].max_workers = bounded; wq->acct[IO_WQ_ACCT_UNBOUND].max_workers = task_rlimit(current, RLIMIT_NPROC); INIT_LIST_HEAD(&wq->wait.entry); wq->wait.func = io_wq_hash_wake; for (i = 0; i < IO_WQ_ACCT_NR; i++) { struct io_wq_acct *acct = &wq->acct[i]; acct->index = i; atomic_set(&acct->nr_running, 0); INIT_WQ_LIST(&acct->work_list); raw_spin_lock_init(&acct->lock); } raw_spin_lock_init(&wq->lock); INIT_HLIST_NULLS_HEAD(&wq->free_list, 0); INIT_LIST_HEAD(&wq->all_list); wq->task = get_task_struct(data->task); atomic_set(&wq->worker_refs, 1); init_completion(&wq->worker_done); ret = cpuhp_state_add_instance_nocalls(io_wq_online, &wq->cpuhp_node); if (ret) goto err; return wq; err: io_wq_put_hash(data->hash); free_cpumask_var(wq->cpu_mask); kfree(wq); return ERR_PTR(ret); } static bool io_task_work_match(struct callback_head *cb, void *data) { struct io_worker *worker; if (cb->func != create_worker_cb && cb->func != create_worker_cont) return false; worker = container_of(cb, struct io_worker, create_work); return worker->wq == data; } void io_wq_exit_start(struct io_wq *wq) { set_bit(IO_WQ_BIT_EXIT, &wq->state); } static void io_wq_cancel_tw_create(struct io_wq *wq) { struct callback_head *cb; while ((cb = task_work_cancel_match(wq->task, io_task_work_match, wq)) != NULL) { struct io_worker *worker; worker = container_of(cb, struct io_worker, create_work); io_worker_cancel_cb(worker); /* * Only the worker continuation helper has worker allocated and * hence needs freeing. */ if (cb->func == create_worker_cont) kfree(worker); } } static void io_wq_exit_workers(struct io_wq *wq) { if (!wq->task) return; io_wq_cancel_tw_create(wq); rcu_read_lock(); io_wq_for_each_worker(wq, io_wq_worker_wake, NULL); rcu_read_unlock(); io_worker_ref_put(wq); wait_for_completion(&wq->worker_done); spin_lock_irq(&wq->hash->wait.lock); list_del_init(&wq->wait.entry); spin_unlock_irq(&wq->hash->wait.lock); put_task_struct(wq->task); wq->task = NULL; } static void io_wq_destroy(struct io_wq *wq) { struct io_cb_cancel_data match = { .fn = io_wq_work_match_all, .cancel_all = true, }; cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node); io_wq_cancel_pending_work(wq, &match); free_cpumask_var(wq->cpu_mask); io_wq_put_hash(wq->hash); kfree(wq); } void io_wq_put_and_exit(struct io_wq *wq) { WARN_ON_ONCE(!test_bit(IO_WQ_BIT_EXIT, &wq->state)); io_wq_exit_workers(wq); io_wq_destroy(wq); } struct online_data { unsigned int cpu; bool online; }; static bool io_wq_worker_affinity(struct io_worker *worker, void *data) { struct online_data *od = data; if (od->online) cpumask_set_cpu(od->cpu, worker->wq->cpu_mask); else cpumask_clear_cpu(od->cpu, worker->wq->cpu_mask); return false; } static int __io_wq_cpu_online(struct io_wq *wq, unsigned int cpu, bool online) { struct online_data od = { .cpu = cpu, .online = online }; rcu_read_lock(); io_wq_for_each_worker(wq, io_wq_worker_affinity, &od); rcu_read_unlock(); return 0; } static int io_wq_cpu_online(unsigned int cpu, struct hlist_node *node) { struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node); return __io_wq_cpu_online(wq, cpu, true); } static int io_wq_cpu_offline(unsigned int cpu, struct hlist_node *node) { struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node); return __io_wq_cpu_online(wq, cpu, false); } int io_wq_cpu_affinity(struct io_uring_task *tctx, cpumask_var_t mask) { if (!tctx || !tctx->io_wq) return -EINVAL; rcu_read_lock(); if (mask) cpumask_copy(tctx->io_wq->cpu_mask, mask); else cpumask_copy(tctx->io_wq->cpu_mask, cpu_possible_mask); rcu_read_unlock(); return 0; } /* * Set max number of unbounded workers, returns old value. If new_count is 0, * then just return the old value. */ int io_wq_max_workers(struct io_wq *wq, int *new_count) { struct io_wq_acct *acct; int prev[IO_WQ_ACCT_NR]; int i; BUILD_BUG_ON((int) IO_WQ_ACCT_BOUND != (int) IO_WQ_BOUND); BUILD_BUG_ON((int) IO_WQ_ACCT_UNBOUND != (int) IO_WQ_UNBOUND); BUILD_BUG_ON((int) IO_WQ_ACCT_NR != 2); for (i = 0; i < IO_WQ_ACCT_NR; i++) { if (new_count[i] > task_rlimit(current, RLIMIT_NPROC)) new_count[i] = task_rlimit(current, RLIMIT_NPROC); } for (i = 0; i < IO_WQ_ACCT_NR; i++) prev[i] = 0; rcu_read_lock(); raw_spin_lock(&wq->lock); for (i = 0; i < IO_WQ_ACCT_NR; i++) { acct = &wq->acct[i]; prev[i] = max_t(int, acct->max_workers, prev[i]); if (new_count[i]) acct->max_workers = new_count[i]; } raw_spin_unlock(&wq->lock); rcu_read_unlock(); for (i = 0; i < IO_WQ_ACCT_NR; i++) new_count[i] = prev[i]; return 0; } static __init int io_wq_init(void) { int ret; ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "io-wq/online", io_wq_cpu_online, io_wq_cpu_offline); if (ret < 0) return ret; io_wq_online = ret; return 0; } subsys_initcall(io_wq_init);
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