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1242 lines
30 KiB
1242 lines
30 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Basic worker thread pool for io_uring |
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* |
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* Copyright (C) 2019 Jens Axboe |
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* |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/init.h> |
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#include <linux/errno.h> |
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#include <linux/sched/signal.h> |
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#include <linux/mm.h> |
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#include <linux/sched/mm.h> |
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#include <linux/percpu.h> |
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#include <linux/slab.h> |
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#include <linux/kthread.h> |
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#include <linux/rculist_nulls.h> |
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#include <linux/fs_struct.h> |
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#include <linux/task_work.h> |
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#include <linux/blk-cgroup.h> |
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#include <linux/audit.h> |
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#include <linux/cpu.h> |
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#include "../kernel/sched/sched.h" |
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#include "io-wq.h" |
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#define WORKER_IDLE_TIMEOUT (5 * HZ) |
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enum { |
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IO_WORKER_F_UP = 1, /* up and active */ |
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IO_WORKER_F_RUNNING = 2, /* account as running */ |
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IO_WORKER_F_FREE = 4, /* worker on free list */ |
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IO_WORKER_F_FIXED = 8, /* static idle worker */ |
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IO_WORKER_F_BOUND = 16, /* is doing bounded work */ |
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}; |
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enum { |
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IO_WQ_BIT_EXIT = 0, /* wq exiting */ |
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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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}; |
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enum { |
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IO_WQE_FLAG_STALLED = 1, /* stalled on hash */ |
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}; |
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/* |
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* One for each thread in a wqe pool |
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*/ |
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struct io_worker { |
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refcount_t ref; |
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unsigned flags; |
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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; |
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struct mm_struct *mm; |
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#ifdef CONFIG_BLK_CGROUP |
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struct cgroup_subsys_state *blkcg_css; |
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#endif |
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const struct cred *cur_creds; |
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const struct cred *saved_creds; |
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struct files_struct *restore_files; |
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struct nsproxy *restore_nsproxy; |
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struct fs_struct *restore_fs; |
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}; |
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#if BITS_PER_LONG == 64 |
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#define IO_WQ_HASH_ORDER 6 |
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#else |
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#define IO_WQ_HASH_ORDER 5 |
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#endif |
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#define IO_WQ_NR_HASH_BUCKETS (1u << IO_WQ_HASH_ORDER) |
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struct io_wqe_acct { |
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unsigned nr_workers; |
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unsigned max_workers; |
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atomic_t nr_running; |
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}; |
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enum { |
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IO_WQ_ACCT_BOUND, |
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IO_WQ_ACCT_UNBOUND, |
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}; |
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/* |
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* Per-node worker thread pool |
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*/ |
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struct io_wqe { |
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struct { |
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raw_spinlock_t lock; |
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struct io_wq_work_list work_list; |
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unsigned long hash_map; |
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unsigned flags; |
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} ____cacheline_aligned_in_smp; |
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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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}; |
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/* |
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* Per io_wq state |
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*/ |
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struct io_wq { |
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struct io_wqe **wqes; |
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unsigned long state; |
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free_work_fn *free_work; |
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io_wq_work_fn *do_work; |
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struct task_struct *manager; |
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struct user_struct *user; |
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refcount_t refs; |
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struct completion done; |
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struct hlist_node cpuhp_node; |
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refcount_t use_refs; |
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}; |
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static enum cpuhp_state io_wq_online; |
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static bool io_worker_get(struct io_worker *worker) |
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{ |
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return refcount_inc_not_zero(&worker->ref); |
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} |
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static void io_worker_release(struct io_worker *worker) |
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{ |
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if (refcount_dec_and_test(&worker->ref)) |
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wake_up_process(worker->task); |
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} |
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/* |
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* Note: drops the wqe->lock if returning true! The caller must re-acquire |
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* the lock in that case. Some callers need to restart handling if this |
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* happens, so we can't just re-acquire the lock on behalf of the caller. |
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*/ |
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static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker) |
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{ |
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bool dropped_lock = false; |
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if (worker->saved_creds) { |
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revert_creds(worker->saved_creds); |
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worker->cur_creds = worker->saved_creds = NULL; |
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} |
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if (current->files != worker->restore_files) { |
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__acquire(&wqe->lock); |
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raw_spin_unlock_irq(&wqe->lock); |
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dropped_lock = true; |
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task_lock(current); |
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current->files = worker->restore_files; |
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current->nsproxy = worker->restore_nsproxy; |
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task_unlock(current); |
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} |
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if (current->fs != worker->restore_fs) |
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current->fs = worker->restore_fs; |
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/* |
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* If we have an active mm, we need to drop the wq lock before unusing |
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* it. If we do, return true and let the caller retry the idle loop. |
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*/ |
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if (worker->mm) { |
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if (!dropped_lock) { |
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__acquire(&wqe->lock); |
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raw_spin_unlock_irq(&wqe->lock); |
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dropped_lock = true; |
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} |
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__set_current_state(TASK_RUNNING); |
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kthread_unuse_mm(worker->mm); |
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mmput(worker->mm); |
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worker->mm = NULL; |
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} |
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#ifdef CONFIG_BLK_CGROUP |
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if (worker->blkcg_css) { |
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kthread_associate_blkcg(NULL); |
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worker->blkcg_css = NULL; |
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} |
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#endif |
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if (current->signal->rlim[RLIMIT_FSIZE].rlim_cur != RLIM_INFINITY) |
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current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; |
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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, |
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struct io_wq_work *work) |
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{ |
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if (work->flags & IO_WQ_WORK_UNBOUND) |
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return &wqe->acct[IO_WQ_ACCT_UNBOUND]; |
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return &wqe->acct[IO_WQ_ACCT_BOUND]; |
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} |
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static inline struct io_wqe_acct *io_wqe_get_acct(struct io_wqe *wqe, |
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struct io_worker *worker) |
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{ |
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if (worker->flags & IO_WORKER_F_BOUND) |
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return &wqe->acct[IO_WQ_ACCT_BOUND]; |
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return &wqe->acct[IO_WQ_ACCT_UNBOUND]; |
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} |
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static void io_worker_exit(struct io_worker *worker) |
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{ |
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struct io_wqe *wqe = worker->wqe; |
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struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker); |
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/* |
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* If we're not at zero, someone else is holding a brief reference |
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* to the worker. Wait for that to go away. |
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*/ |
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set_current_state(TASK_INTERRUPTIBLE); |
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if (!refcount_dec_and_test(&worker->ref)) |
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schedule(); |
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__set_current_state(TASK_RUNNING); |
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preempt_disable(); |
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current->flags &= ~PF_IO_WORKER; |
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if (worker->flags & IO_WORKER_F_RUNNING) |
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atomic_dec(&acct->nr_running); |
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if (!(worker->flags & IO_WORKER_F_BOUND)) |
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atomic_dec(&wqe->wq->user->processes); |
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worker->flags = 0; |
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preempt_enable(); |
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raw_spin_lock_irq(&wqe->lock); |
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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)) { |
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__release(&wqe->lock); |
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raw_spin_lock_irq(&wqe->lock); |
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} |
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acct->nr_workers--; |
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raw_spin_unlock_irq(&wqe->lock); |
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kfree_rcu(worker, rcu); |
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if (refcount_dec_and_test(&wqe->wq->refs)) |
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complete(&wqe->wq->done); |
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} |
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static inline bool io_wqe_run_queue(struct io_wqe *wqe) |
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__must_hold(wqe->lock) |
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{ |
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if (!wq_list_empty(&wqe->work_list) && |
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!(wqe->flags & IO_WQE_FLAG_STALLED)) |
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return true; |
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return false; |
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} |
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/* |
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* Check head of free list for an available worker. If one isn't available, |
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* caller must wake up the wq manager to create one. |
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*/ |
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static bool io_wqe_activate_free_worker(struct io_wqe *wqe) |
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__must_hold(RCU) |
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{ |
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struct hlist_nulls_node *n; |
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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)) |
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return false; |
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worker = hlist_nulls_entry(n, struct io_worker, nulls_node); |
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if (io_worker_get(worker)) { |
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wake_up_process(worker->task); |
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io_worker_release(worker); |
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return true; |
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} |
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return false; |
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} |
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/* |
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* We need a worker. If we find a free one, we're good. If not, and we're |
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* below the max number of workers, wake up the manager to create one. |
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*/ |
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static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct) |
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{ |
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bool ret; |
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/* |
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* Most likely an attempt to queue unbounded work on an io_wq that |
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* wasn't setup with any unbounded workers. |
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*/ |
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if (unlikely(!acct->max_workers)) |
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pr_warn_once("io-wq is not configured for unbound workers"); |
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rcu_read_lock(); |
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ret = io_wqe_activate_free_worker(wqe); |
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rcu_read_unlock(); |
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if (!ret && acct->nr_workers < acct->max_workers) |
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wake_up_process(wqe->wq->manager); |
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} |
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static void io_wqe_inc_running(struct io_wqe *wqe, struct io_worker *worker) |
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{ |
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struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker); |
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atomic_inc(&acct->nr_running); |
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} |
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static void io_wqe_dec_running(struct io_wqe *wqe, struct io_worker *worker) |
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__must_hold(wqe->lock) |
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{ |
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struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker); |
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if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe)) |
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io_wqe_wake_worker(wqe, acct); |
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} |
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static void io_worker_start(struct io_wqe *wqe, struct io_worker *worker) |
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{ |
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allow_kernel_signal(SIGINT); |
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current->flags |= PF_IO_WORKER; |
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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_nsproxy = current->nsproxy; |
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worker->restore_fs = current->fs; |
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io_wqe_inc_running(wqe, worker); |
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} |
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/* |
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* Worker will start processing some work. Move it to the busy list, if |
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* it's currently on the freelist |
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*/ |
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static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker, |
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struct io_wq_work *work) |
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__must_hold(wqe->lock) |
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{ |
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bool worker_bound, work_bound; |
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if (worker->flags & IO_WORKER_F_FREE) { |
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worker->flags &= ~IO_WORKER_F_FREE; |
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hlist_nulls_del_init_rcu(&worker->nulls_node); |
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} |
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/* |
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* If worker is moving from bound to unbound (or vice versa), then |
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* ensure we update the running accounting. |
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*/ |
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worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0; |
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work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0; |
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if (worker_bound != work_bound) { |
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io_wqe_dec_running(wqe, worker); |
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if (work_bound) { |
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worker->flags |= IO_WORKER_F_BOUND; |
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wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--; |
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wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++; |
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atomic_dec(&wqe->wq->user->processes); |
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} else { |
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worker->flags &= ~IO_WORKER_F_BOUND; |
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wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++; |
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wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--; |
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atomic_inc(&wqe->wq->user->processes); |
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} |
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io_wqe_inc_running(wqe, worker); |
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} |
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} |
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/* |
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* No work, worker going to sleep. Move to freelist, and unuse mm if we |
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* have one attached. Dropping the mm may potentially sleep, so we drop |
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* the lock in that case and return success. Since the caller has to |
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* retry the loop in that case (we changed task state), we don't regrab |
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* the lock if we return success. |
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*/ |
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static bool __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker) |
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__must_hold(wqe->lock) |
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{ |
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if (!(worker->flags & IO_WORKER_F_FREE)) { |
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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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} |
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return __io_worker_unuse(wqe, worker); |
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} |
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static inline unsigned int io_get_work_hash(struct io_wq_work *work) |
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{ |
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return work->flags >> IO_WQ_HASH_SHIFT; |
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} |
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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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{ |
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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) { |
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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; |
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} |
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/* hashed, can run if not already running */ |
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hash = io_get_work_hash(work); |
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if (!(wqe->hash_map & BIT(hash))) { |
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wqe->hash_map |= BIT(hash); |
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/* all items with this hash lie in [work, tail] */ |
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tail = wqe->hash_tail[hash]; |
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wqe->hash_tail[hash] = NULL; |
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wq_list_cut(&wqe->work_list, &tail->list, prev); |
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return work; |
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} |
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} |
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return NULL; |
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} |
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static void io_wq_switch_mm(struct io_worker *worker, struct io_wq_work *work) |
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{ |
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if (worker->mm) { |
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kthread_unuse_mm(worker->mm); |
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mmput(worker->mm); |
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worker->mm = NULL; |
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} |
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if (mmget_not_zero(work->identity->mm)) { |
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kthread_use_mm(work->identity->mm); |
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worker->mm = work->identity->mm; |
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return; |
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} |
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|
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/* failed grabbing mm, ensure work gets cancelled */ |
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work->flags |= IO_WQ_WORK_CANCEL; |
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} |
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static inline void io_wq_switch_blkcg(struct io_worker *worker, |
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struct io_wq_work *work) |
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{ |
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#ifdef CONFIG_BLK_CGROUP |
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if (!(work->flags & IO_WQ_WORK_BLKCG)) |
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return; |
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if (work->identity->blkcg_css != worker->blkcg_css) { |
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kthread_associate_blkcg(work->identity->blkcg_css); |
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worker->blkcg_css = work->identity->blkcg_css; |
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} |
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#endif |
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} |
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static void io_wq_switch_creds(struct io_worker *worker, |
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struct io_wq_work *work) |
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{ |
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const struct cred *old_creds = override_creds(work->identity->creds); |
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|
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worker->cur_creds = work->identity->creds; |
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if (worker->saved_creds) |
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put_cred(old_creds); /* creds set by previous switch */ |
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else |
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worker->saved_creds = old_creds; |
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} |
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|
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static void io_impersonate_work(struct io_worker *worker, |
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struct io_wq_work *work) |
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{ |
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if ((work->flags & IO_WQ_WORK_FILES) && |
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current->files != work->identity->files) { |
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task_lock(current); |
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current->files = work->identity->files; |
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current->nsproxy = work->identity->nsproxy; |
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task_unlock(current); |
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if (!work->identity->files) { |
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/* failed grabbing files, ensure work gets cancelled */ |
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work->flags |= IO_WQ_WORK_CANCEL; |
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} |
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} |
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if ((work->flags & IO_WQ_WORK_FS) && current->fs != work->identity->fs) |
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current->fs = work->identity->fs; |
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if ((work->flags & IO_WQ_WORK_MM) && work->identity->mm != worker->mm) |
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io_wq_switch_mm(worker, work); |
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if ((work->flags & IO_WQ_WORK_CREDS) && |
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worker->cur_creds != work->identity->creds) |
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io_wq_switch_creds(worker, work); |
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if (work->flags & IO_WQ_WORK_FSIZE) |
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current->signal->rlim[RLIMIT_FSIZE].rlim_cur = work->identity->fsize; |
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else if (current->signal->rlim[RLIMIT_FSIZE].rlim_cur != RLIM_INFINITY) |
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current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; |
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io_wq_switch_blkcg(worker, work); |
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#ifdef CONFIG_AUDIT |
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current->loginuid = work->identity->loginuid; |
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current->sessionid = work->identity->sessionid; |
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#endif |
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} |
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|
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static void io_assign_current_work(struct io_worker *worker, |
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struct io_wq_work *work) |
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{ |
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if (work) { |
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/* flush pending signals before assigning new work */ |
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if (signal_pending(current)) |
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flush_signals(current); |
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cond_resched(); |
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} |
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|
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#ifdef CONFIG_AUDIT |
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current->loginuid = KUIDT_INIT(AUDIT_UID_UNSET); |
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current->sessionid = AUDIT_SID_UNSET; |
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#endif |
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|
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spin_lock_irq(&worker->lock); |
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worker->cur_work = work; |
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spin_unlock_irq(&worker->lock); |
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} |
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|
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static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work); |
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|
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static void io_worker_handle_work(struct io_worker *worker) |
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__releases(wqe->lock) |
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{ |
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struct io_wqe *wqe = worker->wqe; |
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struct io_wq *wq = wqe->wq; |
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|
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do { |
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struct io_wq_work *work; |
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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 |
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* 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 |
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* can't make progress, any work completion or insertion will |
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* clear the stalled flag. |
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*/ |
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work = io_get_next_work(wqe); |
|
if (work) |
|
__io_worker_busy(wqe, worker, work); |
|
else if (!wq_list_empty(&wqe->work_list)) |
|
wqe->flags |= IO_WQE_FLAG_STALLED; |
|
|
|
raw_spin_unlock_irq(&wqe->lock); |
|
if (!work) |
|
break; |
|
io_assign_current_work(worker, work); |
|
|
|
/* handle a whole dependent link */ |
|
do { |
|
struct io_wq_work *old_work, *next_hashed, *linked; |
|
unsigned int hash = io_get_work_hash(work); |
|
|
|
next_hashed = wq_next_work(work); |
|
io_impersonate_work(worker, work); |
|
/* |
|
* 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; |
|
|
|
old_work = work; |
|
linked = wq->do_work(work); |
|
|
|
work = next_hashed; |
|
if (!work && linked && !io_wq_is_hashed(linked)) { |
|
work = linked; |
|
linked = NULL; |
|
} |
|
io_assign_current_work(worker, work); |
|
wq->free_work(old_work); |
|
|
|
if (linked) |
|
io_wqe_enqueue(wqe, linked); |
|
|
|
if (hash != -1U && !next_hashed) { |
|
raw_spin_lock_irq(&wqe->lock); |
|
wqe->hash_map &= ~BIT_ULL(hash); |
|
wqe->flags &= ~IO_WQE_FLAG_STALLED; |
|
/* skip unnecessary unlock-lock wqe->lock */ |
|
if (!work) |
|
goto get_next; |
|
raw_spin_unlock_irq(&wqe->lock); |
|
} |
|
} while (work); |
|
|
|
raw_spin_lock_irq(&wqe->lock); |
|
} while (1); |
|
} |
|
|
|
static int io_wqe_worker(void *data) |
|
{ |
|
struct io_worker *worker = data; |
|
struct io_wqe *wqe = worker->wqe; |
|
struct io_wq *wq = wqe->wq; |
|
|
|
io_worker_start(wqe, worker); |
|
|
|
while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) { |
|
set_current_state(TASK_INTERRUPTIBLE); |
|
loop: |
|
raw_spin_lock_irq(&wqe->lock); |
|
if (io_wqe_run_queue(wqe)) { |
|
__set_current_state(TASK_RUNNING); |
|
io_worker_handle_work(worker); |
|
goto loop; |
|
} |
|
/* drops the lock on success, retry */ |
|
if (__io_worker_idle(wqe, worker)) { |
|
__release(&wqe->lock); |
|
goto loop; |
|
} |
|
raw_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; |
|
} |
|
|
|
if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) { |
|
raw_spin_lock_irq(&wqe->lock); |
|
if (!wq_list_empty(&wqe->work_list)) |
|
io_worker_handle_work(worker); |
|
else |
|
raw_spin_unlock_irq(&wqe->lock); |
|
} |
|
|
|
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 = 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; |
|
io_wqe_inc_running(wqe, 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 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; |
|
|
|
raw_spin_lock_irq(&wqe->lock); |
|
io_wqe_dec_running(wqe, worker); |
|
raw_spin_unlock_irq(&wqe->lock); |
|
} |
|
|
|
static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index) |
|
{ |
|
struct io_wqe_acct *acct = &wqe->acct[index]; |
|
struct io_worker *worker; |
|
|
|
worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, wqe->node); |
|
if (!worker) |
|
return false; |
|
|
|
refcount_set(&worker->ref, 1); |
|
worker->nulls_node.pprev = NULL; |
|
worker->wqe = wqe; |
|
spin_lock_init(&worker->lock); |
|
|
|
worker->task = kthread_create_on_node(io_wqe_worker, worker, wqe->node, |
|
"io_wqe_worker-%d/%d", index, wqe->node); |
|
if (IS_ERR(worker->task)) { |
|
kfree(worker); |
|
return false; |
|
} |
|
kthread_bind_mask(worker->task, cpumask_of_node(wqe->node)); |
|
|
|
raw_spin_lock_irq(&wqe->lock); |
|
hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list); |
|
list_add_tail_rcu(&worker->all_list, &wqe->all_list); |
|
worker->flags |= IO_WORKER_F_FREE; |
|
if (index == IO_WQ_ACCT_BOUND) |
|
worker->flags |= IO_WORKER_F_BOUND; |
|
if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND)) |
|
worker->flags |= IO_WORKER_F_FIXED; |
|
acct->nr_workers++; |
|
raw_spin_unlock_irq(&wqe->lock); |
|
|
|
if (index == IO_WQ_ACCT_UNBOUND) |
|
atomic_inc(&wq->user->processes); |
|
|
|
refcount_inc(&wq->refs); |
|
wake_up_process(worker->task); |
|
return true; |
|
} |
|
|
|
static inline bool io_wqe_need_worker(struct io_wqe *wqe, int index) |
|
__must_hold(wqe->lock) |
|
{ |
|
struct io_wqe_acct *acct = &wqe->acct[index]; |
|
|
|
/* if we have available workers or no work, no need */ |
|
if (!hlist_nulls_empty(&wqe->free_list) || !io_wqe_run_queue(wqe)) |
|
return false; |
|
return acct->nr_workers < acct->max_workers; |
|
} |
|
|
|
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, |
|
bool (*func)(struct io_worker *, void *), |
|
void *data) |
|
{ |
|
struct io_worker *worker; |
|
bool ret = false; |
|
|
|
list_for_each_entry_rcu(worker, &wqe->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) |
|
{ |
|
wake_up_process(worker->task); |
|
return false; |
|
} |
|
|
|
/* |
|
* Manager thread. Tasked with creating new workers, if we need them. |
|
*/ |
|
static int io_wq_manager(void *data) |
|
{ |
|
struct io_wq *wq = data; |
|
int node; |
|
|
|
/* create fixed workers */ |
|
refcount_set(&wq->refs, 1); |
|
for_each_node(node) { |
|
if (!node_online(node)) |
|
continue; |
|
if (create_io_worker(wq, wq->wqes[node], IO_WQ_ACCT_BOUND)) |
|
continue; |
|
set_bit(IO_WQ_BIT_ERROR, &wq->state); |
|
set_bit(IO_WQ_BIT_EXIT, &wq->state); |
|
goto out; |
|
} |
|
|
|
complete(&wq->done); |
|
|
|
while (!kthread_should_stop()) { |
|
if (current->task_works) |
|
task_work_run(); |
|
|
|
for_each_node(node) { |
|
struct io_wqe *wqe = wq->wqes[node]; |
|
bool fork_worker[2] = { false, false }; |
|
|
|
if (!node_online(node)) |
|
continue; |
|
|
|
raw_spin_lock_irq(&wqe->lock); |
|
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; |
|
raw_spin_unlock_irq(&wqe->lock); |
|
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); |
|
} |
|
set_current_state(TASK_INTERRUPTIBLE); |
|
schedule_timeout(HZ); |
|
} |
|
|
|
if (current->task_works) |
|
task_work_run(); |
|
|
|
out: |
|
if (refcount_dec_and_test(&wq->refs)) { |
|
complete(&wq->done); |
|
return 0; |
|
} |
|
/* if ERROR is set and we get here, we have workers to wake */ |
|
if (test_bit(IO_WQ_BIT_ERROR, &wq->state)) { |
|
rcu_read_lock(); |
|
for_each_node(node) |
|
io_wq_for_each_worker(wq->wqes[node], io_wq_worker_wake, NULL); |
|
rcu_read_unlock(); |
|
} |
|
return 0; |
|
} |
|
|
|
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(); |
|
free_worker = !hlist_nulls_empty(&wqe->free_list); |
|
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; |
|
} |
|
|
|
static void io_run_cancel(struct io_wq_work *work, struct io_wqe *wqe) |
|
{ |
|
struct io_wq *wq = wqe->wq; |
|
|
|
do { |
|
struct io_wq_work *old_work = work; |
|
|
|
work->flags |= IO_WQ_WORK_CANCEL; |
|
work = wq->do_work(work); |
|
wq->free_work(old_work); |
|
} while (work); |
|
} |
|
|
|
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); |
|
} |
|
|
|
static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work) |
|
{ |
|
struct io_wqe_acct *acct = io_work_get_acct(wqe, work); |
|
int work_flags; |
|
unsigned long flags; |
|
|
|
/* |
|
* 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))) { |
|
io_run_cancel(work, wqe); |
|
return; |
|
} |
|
|
|
work_flags = work->flags; |
|
raw_spin_lock_irqsave(&wqe->lock, flags); |
|
io_wqe_insert_work(wqe, work); |
|
wqe->flags &= ~IO_WQE_FLAG_STALLED; |
|
raw_spin_unlock_irqrestore(&wqe->lock, flags); |
|
|
|
if ((work_flags & IO_WQ_WORK_CONCURRENT) || |
|
!atomic_read(&acct->nr_running)) |
|
io_wqe_wake_worker(wqe, acct); |
|
} |
|
|
|
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); |
|
} |
|
|
|
/* |
|
* 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)); |
|
} |
|
|
|
void io_wq_cancel_all(struct io_wq *wq) |
|
{ |
|
int node; |
|
|
|
set_bit(IO_WQ_BIT_CANCEL, &wq->state); |
|
|
|
rcu_read_lock(); |
|
for_each_node(node) { |
|
struct io_wqe *wqe = wq->wqes[node]; |
|
|
|
io_wq_for_each_worker(wqe, io_wqe_worker_send_sig, NULL); |
|
} |
|
rcu_read_unlock(); |
|
} |
|
|
|
struct io_cb_cancel_data { |
|
work_cancel_fn *fn; |
|
void *data; |
|
int nr_running; |
|
int nr_pending; |
|
bool cancel_all; |
|
}; |
|
|
|
static bool io_wq_worker_cancel(struct io_worker *worker, void *data) |
|
{ |
|
struct io_cb_cancel_data *match = data; |
|
unsigned long flags; |
|
|
|
/* |
|
* Hold the lock to avoid ->cur_work going out of scope, caller |
|
* may dereference the passed in work. |
|
*/ |
|
spin_lock_irqsave(&worker->lock, flags); |
|
if (worker->cur_work && |
|
!(worker->cur_work->flags & IO_WQ_WORK_NO_CANCEL) && |
|
match->fn(worker->cur_work, match->data)) { |
|
send_sig(SIGINT, worker->task, 1); |
|
match->nr_running++; |
|
} |
|
spin_unlock_irqrestore(&worker->lock, flags); |
|
|
|
return match->nr_running && !match->cancel_all; |
|
} |
|
|
|
static inline void io_wqe_remove_pending(struct io_wqe *wqe, |
|
struct io_wq_work *work, |
|
struct io_wq_work_node *prev) |
|
{ |
|
unsigned int hash = io_get_work_hash(work); |
|
struct io_wq_work *prev_work = NULL; |
|
|
|
if (io_wq_is_hashed(work) && work == wqe->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) |
|
wqe->hash_tail[hash] = prev_work; |
|
else |
|
wqe->hash_tail[hash] = NULL; |
|
} |
|
wq_list_del(&wqe->work_list, &work->list, prev); |
|
} |
|
|
|
static void io_wqe_cancel_pending_work(struct io_wqe *wqe, |
|
struct io_cb_cancel_data *match) |
|
{ |
|
struct io_wq_work_node *node, *prev; |
|
struct io_wq_work *work; |
|
unsigned long flags; |
|
|
|
retry: |
|
raw_spin_lock_irqsave(&wqe->lock, flags); |
|
wq_list_for_each(node, prev, &wqe->work_list) { |
|
work = container_of(node, struct io_wq_work, list); |
|
if (!match->fn(work, match->data)) |
|
continue; |
|
io_wqe_remove_pending(wqe, work, prev); |
|
raw_spin_unlock_irqrestore(&wqe->lock, flags); |
|
io_run_cancel(work, wqe); |
|
match->nr_pending++; |
|
if (!match->cancel_all) |
|
return; |
|
|
|
/* not safe to continue after unlock */ |
|
goto retry; |
|
} |
|
raw_spin_unlock_irqrestore(&wqe->lock, flags); |
|
} |
|
|
|
static void io_wqe_cancel_running_work(struct io_wqe *wqe, |
|
struct io_cb_cancel_data *match) |
|
{ |
|
rcu_read_lock(); |
|
io_wq_for_each_worker(wqe, 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, |
|
}; |
|
int node; |
|
|
|
/* |
|
* 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. |
|
*/ |
|
for_each_node(node) { |
|
struct io_wqe *wqe = wq->wqes[node]; |
|
|
|
io_wqe_cancel_pending_work(wqe, &match); |
|
if (match.nr_pending && !match.cancel_all) |
|
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 |
|
* as an indication that we attempt to signal cancellation. The |
|
* completion will run normally in this case. |
|
*/ |
|
for_each_node(node) { |
|
struct io_wqe *wqe = wq->wqes[node]; |
|
|
|
io_wqe_cancel_running_work(wqe, &match); |
|
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; |
|
} |
|
|
|
struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data) |
|
{ |
|
int ret = -ENOMEM, node; |
|
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(*wq), GFP_KERNEL); |
|
if (!wq) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
wq->wqes = kcalloc(nr_node_ids, sizeof(struct io_wqe *), GFP_KERNEL); |
|
if (!wq->wqes) |
|
goto err_wq; |
|
|
|
ret = cpuhp_state_add_instance_nocalls(io_wq_online, &wq->cpuhp_node); |
|
if (ret) |
|
goto err_wqes; |
|
|
|
wq->free_work = data->free_work; |
|
wq->do_work = data->do_work; |
|
|
|
/* caller must already hold a reference to this */ |
|
wq->user = data->user; |
|
|
|
ret = -ENOMEM; |
|
for_each_node(node) { |
|
struct io_wqe *wqe; |
|
int alloc_node = node; |
|
|
|
if (!node_online(alloc_node)) |
|
alloc_node = NUMA_NO_NODE; |
|
wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node); |
|
if (!wqe) |
|
goto err; |
|
wq->wqes[node] = wqe; |
|
wqe->node = alloc_node; |
|
wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded; |
|
atomic_set(&wqe->acct[IO_WQ_ACCT_BOUND].nr_running, 0); |
|
if (wq->user) { |
|
wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers = |
|
task_rlimit(current, RLIMIT_NPROC); |
|
} |
|
atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0); |
|
wqe->wq = wq; |
|
raw_spin_lock_init(&wqe->lock); |
|
INIT_WQ_LIST(&wqe->work_list); |
|
INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0); |
|
INIT_LIST_HEAD(&wqe->all_list); |
|
} |
|
|
|
init_completion(&wq->done); |
|
|
|
wq->manager = kthread_create(io_wq_manager, wq, "io_wq_manager"); |
|
if (!IS_ERR(wq->manager)) { |
|
wake_up_process(wq->manager); |
|
wait_for_completion(&wq->done); |
|
if (test_bit(IO_WQ_BIT_ERROR, &wq->state)) { |
|
ret = -ENOMEM; |
|
goto err; |
|
} |
|
refcount_set(&wq->use_refs, 1); |
|
reinit_completion(&wq->done); |
|
return wq; |
|
} |
|
|
|
ret = PTR_ERR(wq->manager); |
|
complete(&wq->done); |
|
err: |
|
cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node); |
|
for_each_node(node) |
|
kfree(wq->wqes[node]); |
|
err_wqes: |
|
kfree(wq->wqes); |
|
err_wq: |
|
kfree(wq); |
|
return ERR_PTR(ret); |
|
} |
|
|
|
bool io_wq_get(struct io_wq *wq, struct io_wq_data *data) |
|
{ |
|
if (data->free_work != wq->free_work || data->do_work != wq->do_work) |
|
return false; |
|
|
|
return refcount_inc_not_zero(&wq->use_refs); |
|
} |
|
|
|
static void __io_wq_destroy(struct io_wq *wq) |
|
{ |
|
int node; |
|
|
|
cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node); |
|
|
|
set_bit(IO_WQ_BIT_EXIT, &wq->state); |
|
if (wq->manager) |
|
kthread_stop(wq->manager); |
|
|
|
rcu_read_lock(); |
|
for_each_node(node) |
|
io_wq_for_each_worker(wq->wqes[node], io_wq_worker_wake, NULL); |
|
rcu_read_unlock(); |
|
|
|
wait_for_completion(&wq->done); |
|
|
|
for_each_node(node) |
|
kfree(wq->wqes[node]); |
|
kfree(wq->wqes); |
|
kfree(wq); |
|
} |
|
|
|
void io_wq_destroy(struct io_wq *wq) |
|
{ |
|
if (refcount_dec_and_test(&wq->use_refs)) |
|
__io_wq_destroy(wq); |
|
} |
|
|
|
struct task_struct *io_wq_get_task(struct io_wq *wq) |
|
{ |
|
return wq->manager; |
|
} |
|
|
|
static bool io_wq_worker_affinity(struct io_worker *worker, void *data) |
|
{ |
|
struct task_struct *task = worker->task; |
|
struct rq_flags rf; |
|
struct rq *rq; |
|
|
|
rq = task_rq_lock(task, &rf); |
|
do_set_cpus_allowed(task, cpumask_of_node(worker->wqe->node)); |
|
task->flags |= PF_NO_SETAFFINITY; |
|
task_rq_unlock(rq, task, &rf); |
|
return false; |
|
} |
|
|
|
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); |
|
int i; |
|
|
|
rcu_read_lock(); |
|
for_each_node(i) |
|
io_wq_for_each_worker(wq->wqes[i], io_wq_worker_affinity, NULL); |
|
rcu_read_unlock(); |
|
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, NULL); |
|
if (ret < 0) |
|
return ret; |
|
io_wq_online = ret; |
|
return 0; |
|
} |
|
subsys_initcall(io_wq_init);
|
|
|