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fs/io-wq.c
26.7 KB
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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/mm.h> #include <linux/mmu_context.h> #include <linux/sched/mm.h> #include <linux/percpu.h> #include <linux/slab.h> #include <linux/kthread.h> #include <linux/rculist_nulls.h> |
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#include <linux/fs_struct.h> |
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#include "io-wq.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_EXITING = 8, /* worker exiting */ IO_WORKER_F_FIXED = 16, /* static idle worker */ |
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IO_WORKER_F_BOUND = 32, /* is doing bounded work */ |
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}; enum { IO_WQ_BIT_EXIT = 0, /* wq exiting */ IO_WQ_BIT_CANCEL = 1, /* cancel work on list */ |
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IO_WQ_BIT_ERROR = 2, /* error on setup */ |
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}; enum { IO_WQE_FLAG_STALLED = 1, /* stalled on hash */ }; /* * One for each thread in a wqe pool */ struct io_worker { refcount_t ref; unsigned flags; struct hlist_nulls_node nulls_node; |
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struct list_head all_list; |
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struct task_struct *task; |
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struct io_wqe *wqe; |
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struct io_wq_work *cur_work; |
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spinlock_t lock; |
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struct rcu_head rcu; struct mm_struct *mm; |
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const struct cred *cur_creds; const struct cred *saved_creds; |
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struct files_struct *restore_files; |
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struct fs_struct *restore_fs; |
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}; |
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#if BITS_PER_LONG == 64 #define IO_WQ_HASH_ORDER 6 #else #define IO_WQ_HASH_ORDER 5 #endif |
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#define IO_WQ_NR_HASH_BUCKETS (1u << IO_WQ_HASH_ORDER) |
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struct io_wqe_acct { unsigned nr_workers; unsigned max_workers; atomic_t nr_running; }; enum { IO_WQ_ACCT_BOUND, IO_WQ_ACCT_UNBOUND, }; |
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/* * Per-node worker thread pool */ struct io_wqe { struct { spinlock_t lock; |
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struct io_wq_work_list work_list; |
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unsigned long hash_map; unsigned flags; } ____cacheline_aligned_in_smp; int node; |
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struct io_wqe_acct acct[2]; |
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struct hlist_nulls_head free_list; |
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struct list_head all_list; |
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struct io_wq *wq; |
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struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS]; |
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}; /* * Per io_wq state */ struct io_wq { struct io_wqe **wqes; unsigned long state; |
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free_work_fn *free_work; |
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struct task_struct *manager; |
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struct user_struct *user; |
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refcount_t refs; struct completion done; |
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refcount_t use_refs; |
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}; |
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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)) wake_up_process(worker->task); } /* * Note: drops the wqe->lock if returning true! The caller must re-acquire * the lock in that case. Some callers need to restart handling if this * happens, so we can't just re-acquire the lock on behalf of the caller. */ static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker) { |
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bool dropped_lock = false; |
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if (worker->saved_creds) { revert_creds(worker->saved_creds); worker->cur_creds = worker->saved_creds = NULL; |
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} |
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if (current->files != worker->restore_files) { __acquire(&wqe->lock); spin_unlock_irq(&wqe->lock); dropped_lock = true; task_lock(current); current->files = worker->restore_files; task_unlock(current); } |
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if (current->fs != worker->restore_fs) current->fs = worker->restore_fs; |
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/* * If we have an active mm, we need to drop the wq lock before unusing * it. If we do, return true and let the caller retry the idle loop. */ if (worker->mm) { |
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if (!dropped_lock) { __acquire(&wqe->lock); spin_unlock_irq(&wqe->lock); dropped_lock = true; } |
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__set_current_state(TASK_RUNNING); set_fs(KERNEL_DS); unuse_mm(worker->mm); mmput(worker->mm); worker->mm = NULL; |
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} |
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return dropped_lock; |
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} |
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static inline struct io_wqe_acct *io_work_get_acct(struct io_wqe *wqe, struct io_wq_work *work) { if (work->flags & IO_WQ_WORK_UNBOUND) return &wqe->acct[IO_WQ_ACCT_UNBOUND]; return &wqe->acct[IO_WQ_ACCT_BOUND]; } static inline struct io_wqe_acct *io_wqe_get_acct(struct io_wqe *wqe, struct io_worker *worker) { if (worker->flags & IO_WORKER_F_BOUND) return &wqe->acct[IO_WQ_ACCT_BOUND]; return &wqe->acct[IO_WQ_ACCT_UNBOUND]; } |
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static void io_worker_exit(struct io_worker *worker) { struct io_wqe *wqe = worker->wqe; |
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struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker); unsigned nr_workers; |
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/* * If we're not at zero, someone else is holding a brief reference * to the worker. Wait for that to go away. */ set_current_state(TASK_INTERRUPTIBLE); if (!refcount_dec_and_test(&worker->ref)) schedule(); __set_current_state(TASK_RUNNING); preempt_disable(); current->flags &= ~PF_IO_WORKER; if (worker->flags & IO_WORKER_F_RUNNING) |
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atomic_dec(&acct->nr_running); if (!(worker->flags & IO_WORKER_F_BOUND)) atomic_dec(&wqe->wq->user->processes); |
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worker->flags = 0; preempt_enable(); spin_lock_irq(&wqe->lock); hlist_nulls_del_rcu(&worker->nulls_node); |
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list_del_rcu(&worker->all_list); |
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if (__io_worker_unuse(wqe, worker)) { __release(&wqe->lock); spin_lock_irq(&wqe->lock); } |
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acct->nr_workers--; nr_workers = wqe->acct[IO_WQ_ACCT_BOUND].nr_workers + wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers; |
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spin_unlock_irq(&wqe->lock); /* all workers gone, wq exit can proceed */ |
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if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs)) |
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complete(&wqe->wq->done); |
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kfree_rcu(worker, rcu); |
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} |
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static inline bool io_wqe_run_queue(struct io_wqe *wqe) __must_hold(wqe->lock) { |
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if (!wq_list_empty(&wqe->work_list) && !(wqe->flags & IO_WQE_FLAG_STALLED)) |
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return true; return false; } /* * Check head of free list for an available worker. If one isn't available, * caller must wake up the wq manager to create one. */ static bool io_wqe_activate_free_worker(struct io_wqe *wqe) __must_hold(RCU) { struct hlist_nulls_node *n; struct io_worker *worker; |
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n = rcu_dereference(hlist_nulls_first_rcu(&wqe->free_list)); |
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if (is_a_nulls(n)) return false; worker = hlist_nulls_entry(n, struct io_worker, nulls_node); if (io_worker_get(worker)) { |
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wake_up_process(worker->task); |
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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, wake up the manager to create one. */ static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct) { bool ret; /* * Most likely an attempt to queue unbounded work on an io_wq that * wasn't setup with any unbounded workers. */ WARN_ON_ONCE(!acct->max_workers); rcu_read_lock(); ret = io_wqe_activate_free_worker(wqe); rcu_read_unlock(); if (!ret && acct->nr_workers < acct->max_workers) wake_up_process(wqe->wq->manager); } static void io_wqe_inc_running(struct io_wqe *wqe, struct io_worker *worker) { struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker); atomic_inc(&acct->nr_running); } static void io_wqe_dec_running(struct io_wqe *wqe, struct io_worker *worker) __must_hold(wqe->lock) { struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker); if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe)) io_wqe_wake_worker(wqe, acct); } |
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static void io_worker_start(struct io_wqe *wqe, struct io_worker *worker) { allow_kernel_signal(SIGINT); current->flags |= PF_IO_WORKER; worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING); |
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worker->restore_files = current->files; |
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worker->restore_fs = current->fs; |
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io_wqe_inc_running(wqe, worker); |
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} /* * 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_wqe *wqe, struct io_worker *worker, struct io_wq_work *work) __must_hold(wqe->lock) { |
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bool worker_bound, work_bound; |
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if (worker->flags & IO_WORKER_F_FREE) { worker->flags &= ~IO_WORKER_F_FREE; hlist_nulls_del_init_rcu(&worker->nulls_node); |
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} |
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/* * If worker is moving from bound to unbound (or vice versa), then * ensure we update the running accounting. */ |
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worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0; work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0; if (worker_bound != work_bound) { |
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io_wqe_dec_running(wqe, worker); if (work_bound) { worker->flags |= IO_WORKER_F_BOUND; wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--; wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++; atomic_dec(&wqe->wq->user->processes); } else { worker->flags &= ~IO_WORKER_F_BOUND; wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++; wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--; atomic_inc(&wqe->wq->user->processes); } io_wqe_inc_running(wqe, worker); } |
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} /* * No work, worker going to sleep. Move to freelist, and unuse mm if we * have one attached. Dropping the mm may potentially sleep, so we drop * the lock in that case and return success. Since the caller has to * retry the loop in that case (we changed task state), we don't regrab * the lock if we return success. */ static bool __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker) __must_hold(wqe->lock) { if (!(worker->flags & IO_WORKER_F_FREE)) { worker->flags |= IO_WORKER_F_FREE; |
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hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list); |
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} return __io_worker_unuse(wqe, worker); } |
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static inline unsigned int io_get_work_hash(struct io_wq_work *work) { return work->flags >> IO_WQ_HASH_SHIFT; } static struct io_wq_work *io_get_next_work(struct io_wqe *wqe) |
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__must_hold(wqe->lock) { |
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struct io_wq_work_node *node, *prev; |
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struct io_wq_work *work, *tail; |
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unsigned int hash; |
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wq_list_for_each(node, prev, &wqe->work_list) { work = container_of(node, struct io_wq_work, list); |
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/* not hashed, can run anytime */ |
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if (!io_wq_is_hashed(work)) { |
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wq_list_del(&wqe->work_list, node, prev); |
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return work; } /* hashed, can run if not already running */ |
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hash = io_get_work_hash(work); if (!(wqe->hash_map & BIT(hash))) { wqe->hash_map |= BIT(hash); |
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/* all items with this hash lie in [work, tail] */ tail = wqe->hash_tail[hash]; wqe->hash_tail[hash] = NULL; wq_list_cut(&wqe->work_list, &tail->list, prev); |
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return work; } } return NULL; } |
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static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work) { if (worker->mm) { unuse_mm(worker->mm); mmput(worker->mm); worker->mm = NULL; } if (!work->mm) { set_fs(KERNEL_DS); return; } if (mmget_not_zero(work->mm)) { use_mm(work->mm); if (!worker->mm) set_fs(USER_DS); worker->mm = work->mm; /* hang on to this mm */ work->mm = NULL; return; } /* failed grabbing mm, ensure work gets cancelled */ work->flags |= IO_WQ_WORK_CANCEL; } static void io_wq_switch_creds(struct io_worker *worker, struct io_wq_work *work) { const struct cred *old_creds = override_creds(work->creds); worker->cur_creds = work->creds; if (worker->saved_creds) put_cred(old_creds); /* creds set by previous switch */ else worker->saved_creds = old_creds; } |
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static void io_impersonate_work(struct io_worker *worker, struct io_wq_work *work) { if (work->files && current->files != work->files) { task_lock(current); current->files = work->files; task_unlock(current); } if (work->fs && current->fs != work->fs) current->fs = work->fs; if (work->mm != worker->mm) io_wq_switch_mm(worker, work); if (worker->cur_creds != work->creds) io_wq_switch_creds(worker, work); } static void io_assign_current_work(struct io_worker *worker, struct io_wq_work *work) { |
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if (work) { /* flush pending signals before assigning new work */ if (signal_pending(current)) flush_signals(current); cond_resched(); } |
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spin_lock_irq(&worker->lock); worker->cur_work = work; spin_unlock_irq(&worker->lock); } |
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static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work); |
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static void io_worker_handle_work(struct io_worker *worker) __releases(wqe->lock) { |
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struct io_wqe *wqe = worker->wqe; struct io_wq *wq = wqe->wq; do { |
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struct io_wq_work *work; |
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unsigned int hash; |
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get_next: |
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/* |
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* 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. */ |
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work = io_get_next_work(wqe); |
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if (work) __io_worker_busy(wqe, worker, work); |
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else if (!wq_list_empty(&wqe->work_list)) |
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wqe->flags |= IO_WQE_FLAG_STALLED; spin_unlock_irq(&wqe->lock); if (!work) break; |
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io_assign_current_work(worker, work); |
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/* handle a whole dependent link */ do { |
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struct io_wq_work *old_work, *next_hashed, *linked; |
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next_hashed = wq_next_work(work); |
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io_impersonate_work(worker, work); |
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/* * OK to set IO_WQ_WORK_CANCEL even for uncancellable * work, the worker function will do the right thing. */ if (test_bit(IO_WQ_BIT_CANCEL, &wq->state)) work->flags |= IO_WQ_WORK_CANCEL; |
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hash = io_get_work_hash(work); |
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linked = old_work = work; linked->func(&linked); linked = (old_work == linked) ? NULL : linked; work = next_hashed; if (!work && linked && !io_wq_is_hashed(linked)) { work = linked; linked = NULL; } io_assign_current_work(worker, work); |
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wq->free_work(old_work); |
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if (linked) io_wqe_enqueue(wqe, linked); if (hash != -1U && !next_hashed) { |
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spin_lock_irq(&wqe->lock); wqe->hash_map &= ~BIT_ULL(hash); wqe->flags &= ~IO_WQE_FLAG_STALLED; |
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/* dependent work is not hashed */ hash = -1U; |
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/* skip unnecessary unlock-lock wqe->lock */ if (!work) goto get_next; spin_unlock_irq(&wqe->lock); |
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} |
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} while (work); |
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spin_lock_irq(&wqe->lock); |
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} while (1); } |
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static int io_wqe_worker(void *data) { struct io_worker *worker = data; struct io_wqe *wqe = worker->wqe; struct io_wq *wq = wqe->wq; |
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io_worker_start(wqe, worker); while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) { |
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set_current_state(TASK_INTERRUPTIBLE); |
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loop: |
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spin_lock_irq(&wqe->lock); if (io_wqe_run_queue(wqe)) { __set_current_state(TASK_RUNNING); io_worker_handle_work(worker); |
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goto loop; |
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} /* drops the lock on success, retry */ if (__io_worker_idle(wqe, worker)) { __release(&wqe->lock); |
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goto loop; |
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} spin_unlock_irq(&wqe->lock); if (signal_pending(current)) flush_signals(current); if (schedule_timeout(WORKER_IDLE_TIMEOUT)) continue; /* timed out, exit unless we're the fixed worker */ if (test_bit(IO_WQ_BIT_EXIT, &wq->state) || !(worker->flags & IO_WORKER_F_FIXED)) break; } |
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if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) { spin_lock_irq(&wqe->lock); |
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if (!wq_list_empty(&wqe->work_list)) |
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io_worker_handle_work(worker); else spin_unlock_irq(&wqe->lock); } io_worker_exit(worker); return 0; } /* |
771b53d03
|
581 582 583 584 585 586 587 588 589 590 591 592 |
* 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 = kthread_data(tsk); struct io_wqe *wqe = worker->wqe; if (!(worker->flags & IO_WORKER_F_UP)) return; if (worker->flags & IO_WORKER_F_RUNNING) return; worker->flags |= IO_WORKER_F_RUNNING; |
c5def4ab8
|
593 |
io_wqe_inc_running(wqe, worker); |
771b53d03
|
594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 |
} /* * 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 have the manager * set one up. */ void io_wq_worker_sleeping(struct task_struct *tsk) { struct io_worker *worker = kthread_data(tsk); struct io_wqe *wqe = worker->wqe; if (!(worker->flags & IO_WORKER_F_UP)) return; if (!(worker->flags & IO_WORKER_F_RUNNING)) return; worker->flags &= ~IO_WORKER_F_RUNNING; spin_lock_irq(&wqe->lock); |
c5def4ab8
|
614 |
io_wqe_dec_running(wqe, worker); |
771b53d03
|
615 616 |
spin_unlock_irq(&wqe->lock); } |
b60fda600
|
617 |
static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index) |
771b53d03
|
618 |
{ |
c5def4ab8
|
619 |
struct io_wqe_acct *acct =&wqe->acct[index]; |
771b53d03
|
620 |
struct io_worker *worker; |
ad6e005ca
|
621 |
worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, wqe->node); |
771b53d03
|
622 |
if (!worker) |
b60fda600
|
623 |
return false; |
771b53d03
|
624 625 626 |
refcount_set(&worker->ref, 1); worker->nulls_node.pprev = NULL; |
771b53d03
|
627 |
worker->wqe = wqe; |
36c2f9223
|
628 |
spin_lock_init(&worker->lock); |
771b53d03
|
629 630 |
worker->task = kthread_create_on_node(io_wqe_worker, worker, wqe->node, |
c5def4ab8
|
631 |
"io_wqe_worker-%d/%d", index, wqe->node); |
771b53d03
|
632 633 |
if (IS_ERR(worker->task)) { kfree(worker); |
b60fda600
|
634 |
return false; |
771b53d03
|
635 636 637 |
} spin_lock_irq(&wqe->lock); |
021d1cdda
|
638 |
hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list); |
e61df66c6
|
639 |
list_add_tail_rcu(&worker->all_list, &wqe->all_list); |
771b53d03
|
640 |
worker->flags |= IO_WORKER_F_FREE; |
c5def4ab8
|
641 642 643 |
if (index == IO_WQ_ACCT_BOUND) worker->flags |= IO_WORKER_F_BOUND; if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND)) |
771b53d03
|
644 |
worker->flags |= IO_WORKER_F_FIXED; |
c5def4ab8
|
645 |
acct->nr_workers++; |
771b53d03
|
646 |
spin_unlock_irq(&wqe->lock); |
c5def4ab8
|
647 648 |
if (index == IO_WQ_ACCT_UNBOUND) atomic_inc(&wq->user->processes); |
771b53d03
|
649 |
wake_up_process(worker->task); |
b60fda600
|
650 |
return true; |
771b53d03
|
651 |
} |
c5def4ab8
|
652 |
static inline bool io_wqe_need_worker(struct io_wqe *wqe, int index) |
771b53d03
|
653 654 |
__must_hold(wqe->lock) { |
c5def4ab8
|
655 |
struct io_wqe_acct *acct = &wqe->acct[index]; |
771b53d03
|
656 |
|
c5def4ab8
|
657 |
/* if we have available workers or no work, no need */ |
021d1cdda
|
658 |
if (!hlist_nulls_empty(&wqe->free_list) || !io_wqe_run_queue(wqe)) |
c5def4ab8
|
659 660 |
return false; return acct->nr_workers < acct->max_workers; |
771b53d03
|
661 662 663 664 665 666 667 668 |
} /* * Manager thread. Tasked with creating new workers, if we need them. */ static int io_wq_manager(void *data) { struct io_wq *wq = data; |
3fc50ab55
|
669 670 |
int workers_to_create = num_possible_nodes(); int node; |
771b53d03
|
671 |
|
b60fda600
|
672 |
/* create fixed workers */ |
3fc50ab55
|
673 674 |
refcount_set(&wq->refs, workers_to_create); for_each_node(node) { |
7563439ad
|
675 676 |
if (!node_online(node)) continue; |
3fc50ab55
|
677 678 679 |
if (!create_io_worker(wq, wq->wqes[node], IO_WQ_ACCT_BOUND)) goto err; workers_to_create--; |
b60fda600
|
680 |
} |
771b53d03
|
681 |
|
7563439ad
|
682 683 |
while (workers_to_create--) refcount_dec(&wq->refs); |
b60fda600
|
684 685 686 |
complete(&wq->done); while (!kthread_should_stop()) { |
3fc50ab55
|
687 688 |
for_each_node(node) { struct io_wqe *wqe = wq->wqes[node]; |
c5def4ab8
|
689 |
bool fork_worker[2] = { false, false }; |
771b53d03
|
690 |
|
7563439ad
|
691 692 |
if (!node_online(node)) continue; |
771b53d03
|
693 |
spin_lock_irq(&wqe->lock); |
c5def4ab8
|
694 695 696 697 |
if (io_wqe_need_worker(wqe, IO_WQ_ACCT_BOUND)) fork_worker[IO_WQ_ACCT_BOUND] = true; if (io_wqe_need_worker(wqe, IO_WQ_ACCT_UNBOUND)) fork_worker[IO_WQ_ACCT_UNBOUND] = true; |
771b53d03
|
698 |
spin_unlock_irq(&wqe->lock); |
c5def4ab8
|
699 700 701 702 |
if (fork_worker[IO_WQ_ACCT_BOUND]) create_io_worker(wq, wqe, IO_WQ_ACCT_BOUND); if (fork_worker[IO_WQ_ACCT_UNBOUND]) create_io_worker(wq, wqe, IO_WQ_ACCT_UNBOUND); |
771b53d03
|
703 704 705 706 707 708 |
} set_current_state(TASK_INTERRUPTIBLE); schedule_timeout(HZ); } return 0; |
b60fda600
|
709 710 711 |
err: set_bit(IO_WQ_BIT_ERROR, &wq->state); set_bit(IO_WQ_BIT_EXIT, &wq->state); |
3fc50ab55
|
712 |
if (refcount_sub_and_test(workers_to_create, &wq->refs)) |
b60fda600
|
713 714 |
complete(&wq->done); return 0; |
771b53d03
|
715 |
} |
c5def4ab8
|
716 717 718 719 720 721 722 723 724 725 726 |
static bool io_wq_can_queue(struct io_wqe *wqe, struct io_wqe_acct *acct, struct io_wq_work *work) { bool free_worker; if (!(work->flags & IO_WQ_WORK_UNBOUND)) return true; if (atomic_read(&acct->nr_running)) return true; rcu_read_lock(); |
021d1cdda
|
727 |
free_worker = !hlist_nulls_empty(&wqe->free_list); |
c5def4ab8
|
728 729 730 731 732 733 734 735 736 737 |
rcu_read_unlock(); if (free_worker) return true; if (atomic_read(&wqe->wq->user->processes) >= acct->max_workers && !(capable(CAP_SYS_RESOURCE) || capable(CAP_SYS_ADMIN))) return false; return true; } |
e9fd93965
|
738 |
static void io_run_cancel(struct io_wq_work *work, struct io_wqe *wqe) |
fc04c39ba
|
739 |
{ |
e9fd93965
|
740 |
struct io_wq *wq = wqe->wq; |
fc04c39ba
|
741 742 743 744 745 746 |
do { struct io_wq_work *old_work = work; work->flags |= IO_WQ_WORK_CANCEL; work->func(&work); work = (work == old_work) ? NULL : work; |
e9fd93965
|
747 |
wq->free_work(old_work); |
fc04c39ba
|
748 749 |
} while (work); } |
86f3cd1b5
|
750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 |
static void io_wqe_insert_work(struct io_wqe *wqe, struct io_wq_work *work) { unsigned int hash; struct io_wq_work *tail; if (!io_wq_is_hashed(work)) { append: wq_list_add_tail(&work->list, &wqe->work_list); return; } hash = io_get_work_hash(work); tail = wqe->hash_tail[hash]; wqe->hash_tail[hash] = work; if (!tail) goto append; wq_list_add_after(&work->list, &tail->list, &wqe->work_list); } |
771b53d03
|
769 770 |
static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work) { |
c5def4ab8
|
771 |
struct io_wqe_acct *acct = io_work_get_acct(wqe, work); |
895e2ca0f
|
772 |
int work_flags; |
771b53d03
|
773 |
unsigned long flags; |
c5def4ab8
|
774 775 776 777 778 779 780 |
/* * Do early check to see if we need a new unbound worker, and if we do, * if we're allowed to do so. This isn't 100% accurate as there's a * gap between this check and incrementing the value, but that's OK. * It's close enough to not be an issue, fork() has the same delay. */ if (unlikely(!io_wq_can_queue(wqe, acct, work))) { |
e9fd93965
|
781 |
io_run_cancel(work, wqe); |
c5def4ab8
|
782 783 |
return; } |
895e2ca0f
|
784 |
work_flags = work->flags; |
771b53d03
|
785 |
spin_lock_irqsave(&wqe->lock, flags); |
86f3cd1b5
|
786 |
io_wqe_insert_work(wqe, work); |
771b53d03
|
787 788 |
wqe->flags &= ~IO_WQE_FLAG_STALLED; spin_unlock_irqrestore(&wqe->lock, flags); |
895e2ca0f
|
789 790 |
if ((work_flags & IO_WQ_WORK_CONCURRENT) || !atomic_read(&acct->nr_running)) |
c5def4ab8
|
791 |
io_wqe_wake_worker(wqe, acct); |
771b53d03
|
792 793 794 795 796 797 798 799 800 801 |
} void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work) { struct io_wqe *wqe = wq->wqes[numa_node_id()]; io_wqe_enqueue(wqe, work); } /* |
8766dd516
|
802 803 |
* Work items that hash to the same value will not be done in parallel. * Used to limit concurrent writes, generally hashed by inode. |
771b53d03
|
804 |
*/ |
8766dd516
|
805 |
void io_wq_hash_work(struct io_wq_work *work, void *val) |
771b53d03
|
806 |
{ |
8766dd516
|
807 |
unsigned int bit; |
771b53d03
|
808 809 810 |
bit = hash_ptr(val, IO_WQ_HASH_ORDER); work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT)); |
771b53d03
|
811 812 813 814 815 816 817 818 819 820 821 822 823 |
} static bool io_wqe_worker_send_sig(struct io_worker *worker, void *data) { send_sig(SIGINT, worker->task, 1); return false; } /* * 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_wqe *wqe, |
771b53d03
|
824 825 826 |
bool (*func)(struct io_worker *, void *), void *data) { |
771b53d03
|
827 828 |
struct io_worker *worker; bool ret = false; |
e61df66c6
|
829 |
list_for_each_entry_rcu(worker, &wqe->all_list, all_list) { |
771b53d03
|
830 |
if (io_worker_get(worker)) { |
7563439ad
|
831 832 833 |
/* no task if node is/was offline */ if (worker->task) ret = func(worker, data); |
771b53d03
|
834 835 836 837 838 |
io_worker_release(worker); if (ret) break; } } |
e61df66c6
|
839 |
|
771b53d03
|
840 841 842 843 844 |
return ret; } void io_wq_cancel_all(struct io_wq *wq) { |
3fc50ab55
|
845 |
int node; |
771b53d03
|
846 847 |
set_bit(IO_WQ_BIT_CANCEL, &wq->state); |
771b53d03
|
848 |
rcu_read_lock(); |
3fc50ab55
|
849 850 |
for_each_node(node) { struct io_wqe *wqe = wq->wqes[node]; |
771b53d03
|
851 |
|
e61df66c6
|
852 |
io_wq_for_each_worker(wqe, io_wqe_worker_send_sig, NULL); |
771b53d03
|
853 854 855 |
} rcu_read_unlock(); } |
62755e35d
|
856 |
struct io_cb_cancel_data { |
2293b4195
|
857 858 |
work_cancel_fn *fn; void *data; |
62755e35d
|
859 |
}; |
2293b4195
|
860 |
static bool io_wq_worker_cancel(struct io_worker *worker, void *data) |
62755e35d
|
861 |
{ |
2293b4195
|
862 |
struct io_cb_cancel_data *match = data; |
6f72653e7
|
863 |
unsigned long flags; |
62755e35d
|
864 865 866 867 |
bool ret = false; /* * Hold the lock to avoid ->cur_work going out of scope, caller |
36c2f9223
|
868 |
* may dereference the passed in work. |
62755e35d
|
869 |
*/ |
36c2f9223
|
870 |
spin_lock_irqsave(&worker->lock, flags); |
62755e35d
|
871 |
if (worker->cur_work && |
0c9d5ccd2
|
872 |
!(worker->cur_work->flags & IO_WQ_WORK_NO_CANCEL) && |
2293b4195
|
873 |
match->fn(worker->cur_work, match->data)) { |
771b53d03
|
874 |
send_sig(SIGINT, worker->task, 1); |
36c2f9223
|
875 |
ret = true; |
771b53d03
|
876 |
} |
36c2f9223
|
877 |
spin_unlock_irqrestore(&worker->lock, flags); |
771b53d03
|
878 |
|
36c2f9223
|
879 |
return ret; |
771b53d03
|
880 881 882 |
} static enum io_wq_cancel io_wqe_cancel_work(struct io_wqe *wqe, |
2293b4195
|
883 |
struct io_cb_cancel_data *match) |
771b53d03
|
884 |
{ |
6206f0e18
|
885 |
struct io_wq_work_node *node, *prev; |
771b53d03
|
886 |
struct io_wq_work *work; |
6f72653e7
|
887 |
unsigned long flags; |
771b53d03
|
888 |
bool found = false; |
771b53d03
|
889 890 891 892 893 |
/* * 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. */ |
6f72653e7
|
894 |
spin_lock_irqsave(&wqe->lock, flags); |
6206f0e18
|
895 896 |
wq_list_for_each(node, prev, &wqe->work_list) { work = container_of(node, struct io_wq_work, list); |
00bcda13d
|
897 |
if (match->fn(work, match->data)) { |
86f3cd1b5
|
898 |
wq_list_del(&wqe->work_list, node, prev); |
771b53d03
|
899 900 901 902 |
found = true; break; } } |
6f72653e7
|
903 |
spin_unlock_irqrestore(&wqe->lock, flags); |
771b53d03
|
904 905 |
if (found) { |
e9fd93965
|
906 |
io_run_cancel(work, wqe); |
771b53d03
|
907 908 909 910 911 912 |
return IO_WQ_CANCEL_OK; } /* * Now check if a free (going busy) or busy worker has the work * currently running. If we find it there, we'll return CANCEL_RUNNING |
d195a66e3
|
913 |
* as an indication that we attempt to signal cancellation. The |
771b53d03
|
914 915 916 |
* completion will run normally in this case. */ rcu_read_lock(); |
00bcda13d
|
917 |
found = io_wq_for_each_worker(wqe, io_wq_worker_cancel, match); |
771b53d03
|
918 919 920 |
rcu_read_unlock(); return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND; } |
2293b4195
|
921 922 |
enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel, void *data) |
771b53d03
|
923 |
{ |
2293b4195
|
924 925 926 |
struct io_cb_cancel_data match = { .fn = cancel, .data = data, |
00bcda13d
|
927 |
}; |
771b53d03
|
928 |
enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND; |
3fc50ab55
|
929 |
int node; |
771b53d03
|
930 |
|
3fc50ab55
|
931 932 |
for_each_node(node) { struct io_wqe *wqe = wq->wqes[node]; |
771b53d03
|
933 |
|
00bcda13d
|
934 |
ret = io_wqe_cancel_work(wqe, &match); |
771b53d03
|
935 936 937 938 939 940 |
if (ret != IO_WQ_CANCEL_NOTFOUND) break; } return ret; } |
2293b4195
|
941 942 943 944 945 946 947 948 949 |
static bool io_wq_io_cb_cancel_data(struct io_wq_work *work, void *data) { return work == data; } enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork) { return io_wq_cancel_cb(wq, io_wq_io_cb_cancel_data, (void *)cwork); } |
36282881a
|
950 951 952 |
static bool io_wq_pid_match(struct io_wq_work *work, void *data) { pid_t pid = (pid_t) (unsigned long) data; |
2293b4195
|
953 |
return work->task_pid == pid; |
36282881a
|
954 955 956 957 |
} enum io_wq_cancel io_wq_cancel_pid(struct io_wq *wq, pid_t pid) { |
2293b4195
|
958 |
void *data = (void *) (unsigned long) pid; |
36282881a
|
959 |
|
2293b4195
|
960 |
return io_wq_cancel_cb(wq, io_wq_pid_match, data); |
36282881a
|
961 |
} |
576a347b7
|
962 |
struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data) |
771b53d03
|
963 |
{ |
3fc50ab55
|
964 |
int ret = -ENOMEM, node; |
771b53d03
|
965 |
struct io_wq *wq; |
e9fd93965
|
966 967 |
if (WARN_ON_ONCE(!data->free_work)) return ERR_PTR(-EINVAL); |
ad6e005ca
|
968 |
wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
771b53d03
|
969 970 |
if (!wq) return ERR_PTR(-ENOMEM); |
3fc50ab55
|
971 |
wq->wqes = kcalloc(nr_node_ids, sizeof(struct io_wqe *), GFP_KERNEL); |
771b53d03
|
972 973 974 975 |
if (!wq->wqes) { kfree(wq); return ERR_PTR(-ENOMEM); } |
e9fd93965
|
976 |
wq->free_work = data->free_work; |
7d7230652
|
977 |
|
c5def4ab8
|
978 |
/* caller must already hold a reference to this */ |
576a347b7
|
979 |
wq->user = data->user; |
c5def4ab8
|
980 |
|
3fc50ab55
|
981 |
for_each_node(node) { |
771b53d03
|
982 |
struct io_wqe *wqe; |
7563439ad
|
983 |
int alloc_node = node; |
771b53d03
|
984 |
|
7563439ad
|
985 986 987 |
if (!node_online(alloc_node)) alloc_node = NUMA_NO_NODE; wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node); |
771b53d03
|
988 |
if (!wqe) |
3fc50ab55
|
989 990 |
goto err; wq->wqes[node] = wqe; |
7563439ad
|
991 |
wqe->node = alloc_node; |
c5def4ab8
|
992 993 |
wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded; atomic_set(&wqe->acct[IO_WQ_ACCT_BOUND].nr_running, 0); |
576a347b7
|
994 |
if (wq->user) { |
c5def4ab8
|
995 996 997 998 |
wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers = task_rlimit(current, RLIMIT_NPROC); } atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0); |
771b53d03
|
999 1000 |
wqe->wq = wq; spin_lock_init(&wqe->lock); |
6206f0e18
|
1001 |
INIT_WQ_LIST(&wqe->work_list); |
021d1cdda
|
1002 |
INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0); |
e61df66c6
|
1003 |
INIT_LIST_HEAD(&wqe->all_list); |
771b53d03
|
1004 1005 1006 |
} init_completion(&wq->done); |
771b53d03
|
1007 1008 1009 |
wq->manager = kthread_create(io_wq_manager, wq, "io_wq_manager"); if (!IS_ERR(wq->manager)) { wake_up_process(wq->manager); |
b60fda600
|
1010 1011 1012 1013 1014 |
wait_for_completion(&wq->done); if (test_bit(IO_WQ_BIT_ERROR, &wq->state)) { ret = -ENOMEM; goto err; } |
848f7e188
|
1015 |
refcount_set(&wq->use_refs, 1); |
b60fda600
|
1016 |
reinit_completion(&wq->done); |
771b53d03
|
1017 1018 1019 1020 |
return wq; } ret = PTR_ERR(wq->manager); |
771b53d03
|
1021 |
complete(&wq->done); |
b60fda600
|
1022 |
err: |
3fc50ab55
|
1023 1024 |
for_each_node(node) kfree(wq->wqes[node]); |
b60fda600
|
1025 1026 |
kfree(wq->wqes); kfree(wq); |
771b53d03
|
1027 1028 |
return ERR_PTR(ret); } |
eba6f5a33
|
1029 1030 |
bool io_wq_get(struct io_wq *wq, struct io_wq_data *data) { |
e9fd93965
|
1031 |
if (data->free_work != wq->free_work) |
eba6f5a33
|
1032 1033 1034 1035 |
return false; return refcount_inc_not_zero(&wq->use_refs); } |
771b53d03
|
1036 1037 1038 1039 1040 |
static bool io_wq_worker_wake(struct io_worker *worker, void *data) { wake_up_process(worker->task); return false; } |
848f7e188
|
1041 |
static void __io_wq_destroy(struct io_wq *wq) |
771b53d03
|
1042 |
{ |
3fc50ab55
|
1043 |
int node; |
771b53d03
|
1044 |
|
b60fda600
|
1045 1046 |
set_bit(IO_WQ_BIT_EXIT, &wq->state); if (wq->manager) |
771b53d03
|
1047 |
kthread_stop(wq->manager); |
771b53d03
|
1048 1049 |
rcu_read_lock(); |
3fc50ab55
|
1050 1051 |
for_each_node(node) io_wq_for_each_worker(wq->wqes[node], io_wq_worker_wake, NULL); |
771b53d03
|
1052 1053 1054 |
rcu_read_unlock(); wait_for_completion(&wq->done); |
3fc50ab55
|
1055 1056 |
for_each_node(node) kfree(wq->wqes[node]); |
771b53d03
|
1057 1058 1059 |
kfree(wq->wqes); kfree(wq); } |
848f7e188
|
1060 1061 1062 1063 1064 1065 |
void io_wq_destroy(struct io_wq *wq) { if (refcount_dec_and_test(&wq->use_refs)) __io_wq_destroy(wq); } |