diff options
Diffstat (limited to 'fs/btrfs/async-thread.c')
| -rw-r--r-- | fs/btrfs/async-thread.c | 365 |
1 files changed, 365 insertions, 0 deletions
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c new file mode 100644 index 000000000..df9932b00 --- /dev/null +++ b/fs/btrfs/async-thread.c @@ -0,0 +1,365 @@ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + * Copyright (C) 2014 Fujitsu. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#include <linux/kthread.h> +#include <linux/slab.h> +#include <linux/list.h> +#include <linux/spinlock.h> +#include <linux/freezer.h> +#include "async-thread.h" +#include "ctree.h" + +#define WORK_DONE_BIT 0 +#define WORK_ORDER_DONE_BIT 1 +#define WORK_HIGH_PRIO_BIT 2 + +#define NO_THRESHOLD (-1) +#define DFT_THRESHOLD (32) + +struct __btrfs_workqueue { + struct workqueue_struct *normal_wq; + /* List head pointing to ordered work list */ + struct list_head ordered_list; + + /* Spinlock for ordered_list */ + spinlock_t list_lock; + + /* Thresholding related variants */ + atomic_t pending; + int max_active; + int current_max; + int thresh; + unsigned int count; + spinlock_t thres_lock; +}; + +struct btrfs_workqueue { + struct __btrfs_workqueue *normal; + struct __btrfs_workqueue *high; +}; + +static void normal_work_helper(struct btrfs_work *work); + +#define BTRFS_WORK_HELPER(name) \ +void btrfs_##name(struct work_struct *arg) \ +{ \ + struct btrfs_work *work = container_of(arg, struct btrfs_work, \ + normal_work); \ + normal_work_helper(work); \ +} + +BTRFS_WORK_HELPER(worker_helper); +BTRFS_WORK_HELPER(delalloc_helper); +BTRFS_WORK_HELPER(flush_delalloc_helper); +BTRFS_WORK_HELPER(cache_helper); +BTRFS_WORK_HELPER(submit_helper); +BTRFS_WORK_HELPER(fixup_helper); +BTRFS_WORK_HELPER(endio_helper); +BTRFS_WORK_HELPER(endio_meta_helper); +BTRFS_WORK_HELPER(endio_meta_write_helper); +BTRFS_WORK_HELPER(endio_raid56_helper); +BTRFS_WORK_HELPER(endio_repair_helper); +BTRFS_WORK_HELPER(rmw_helper); +BTRFS_WORK_HELPER(endio_write_helper); +BTRFS_WORK_HELPER(freespace_write_helper); +BTRFS_WORK_HELPER(delayed_meta_helper); +BTRFS_WORK_HELPER(readahead_helper); +BTRFS_WORK_HELPER(qgroup_rescan_helper); +BTRFS_WORK_HELPER(extent_refs_helper); +BTRFS_WORK_HELPER(scrub_helper); +BTRFS_WORK_HELPER(scrubwrc_helper); +BTRFS_WORK_HELPER(scrubnc_helper); + +static struct __btrfs_workqueue * +__btrfs_alloc_workqueue(const char *name, unsigned int flags, int max_active, + int thresh) +{ + struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS); + + if (!ret) + return NULL; + + ret->max_active = max_active; + atomic_set(&ret->pending, 0); + if (thresh == 0) + thresh = DFT_THRESHOLD; + /* For low threshold, disabling threshold is a better choice */ + if (thresh < DFT_THRESHOLD) { + ret->current_max = max_active; + ret->thresh = NO_THRESHOLD; + } else { + ret->current_max = 1; + ret->thresh = thresh; + } + + if (flags & WQ_HIGHPRI) + ret->normal_wq = alloc_workqueue("%s-%s-high", flags, + ret->max_active, + "btrfs", name); + else + ret->normal_wq = alloc_workqueue("%s-%s", flags, + ret->max_active, "btrfs", + name); + if (!ret->normal_wq) { + kfree(ret); + return NULL; + } + + INIT_LIST_HEAD(&ret->ordered_list); + spin_lock_init(&ret->list_lock); + spin_lock_init(&ret->thres_lock); + trace_btrfs_workqueue_alloc(ret, name, flags & WQ_HIGHPRI); + return ret; +} + +static inline void +__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq); + +struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name, + unsigned int flags, + int max_active, + int thresh) +{ + struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS); + + if (!ret) + return NULL; + + ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI, + max_active, thresh); + if (!ret->normal) { + kfree(ret); + return NULL; + } + + if (flags & WQ_HIGHPRI) { + ret->high = __btrfs_alloc_workqueue(name, flags, max_active, + thresh); + if (!ret->high) { + __btrfs_destroy_workqueue(ret->normal); + kfree(ret); + return NULL; + } + } + return ret; +} + +/* + * Hook for threshold which will be called in btrfs_queue_work. + * This hook WILL be called in IRQ handler context, + * so workqueue_set_max_active MUST NOT be called in this hook + */ +static inline void thresh_queue_hook(struct __btrfs_workqueue *wq) +{ + if (wq->thresh == NO_THRESHOLD) + return; + atomic_inc(&wq->pending); +} + +/* + * Hook for threshold which will be called before executing the work, + * This hook is called in kthread content. + * So workqueue_set_max_active is called here. + */ +static inline void thresh_exec_hook(struct __btrfs_workqueue *wq) +{ + int new_max_active; + long pending; + int need_change = 0; + + if (wq->thresh == NO_THRESHOLD) + return; + + atomic_dec(&wq->pending); + spin_lock(&wq->thres_lock); + /* + * Use wq->count to limit the calling frequency of + * workqueue_set_max_active. + */ + wq->count++; + wq->count %= (wq->thresh / 4); + if (!wq->count) + goto out; + new_max_active = wq->current_max; + + /* + * pending may be changed later, but it's OK since we really + * don't need it so accurate to calculate new_max_active. + */ + pending = atomic_read(&wq->pending); + if (pending > wq->thresh) + new_max_active++; + if (pending < wq->thresh / 2) + new_max_active--; + new_max_active = clamp_val(new_max_active, 1, wq->max_active); + if (new_max_active != wq->current_max) { + need_change = 1; + wq->current_max = new_max_active; + } +out: + spin_unlock(&wq->thres_lock); + + if (need_change) { + workqueue_set_max_active(wq->normal_wq, wq->current_max); + } +} + +static void run_ordered_work(struct __btrfs_workqueue *wq) +{ + struct list_head *list = &wq->ordered_list; + struct btrfs_work *work; + spinlock_t *lock = &wq->list_lock; + unsigned long flags; + + while (1) { + spin_lock_irqsave(lock, flags); + if (list_empty(list)) + break; + work = list_entry(list->next, struct btrfs_work, + ordered_list); + if (!test_bit(WORK_DONE_BIT, &work->flags)) + break; + + /* + * we are going to call the ordered done function, but + * we leave the work item on the list as a barrier so + * that later work items that are done don't have their + * functions called before this one returns + */ + if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags)) + break; + trace_btrfs_ordered_sched(work); + spin_unlock_irqrestore(lock, flags); + work->ordered_func(work); + + /* now take the lock again and drop our item from the list */ + spin_lock_irqsave(lock, flags); + list_del(&work->ordered_list); + spin_unlock_irqrestore(lock, flags); + + /* + * we don't want to call the ordered free functions + * with the lock held though + */ + work->ordered_free(work); + trace_btrfs_all_work_done(work); + } + spin_unlock_irqrestore(lock, flags); +} + +static void normal_work_helper(struct btrfs_work *work) +{ + struct __btrfs_workqueue *wq; + int need_order = 0; + + /* + * We should not touch things inside work in the following cases: + * 1) after work->func() if it has no ordered_free + * Since the struct is freed in work->func(). + * 2) after setting WORK_DONE_BIT + * The work may be freed in other threads almost instantly. + * So we save the needed things here. + */ + if (work->ordered_func) + need_order = 1; + wq = work->wq; + + trace_btrfs_work_sched(work); + thresh_exec_hook(wq); + work->func(work); + if (need_order) { + set_bit(WORK_DONE_BIT, &work->flags); + run_ordered_work(wq); + } + if (!need_order) + trace_btrfs_all_work_done(work); +} + +void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t uniq_func, + btrfs_func_t func, + btrfs_func_t ordered_func, + btrfs_func_t ordered_free) +{ + work->func = func; + work->ordered_func = ordered_func; + work->ordered_free = ordered_free; + INIT_WORK(&work->normal_work, uniq_func); + INIT_LIST_HEAD(&work->ordered_list); + work->flags = 0; +} + +static inline void __btrfs_queue_work(struct __btrfs_workqueue *wq, + struct btrfs_work *work) +{ + unsigned long flags; + + work->wq = wq; + thresh_queue_hook(wq); + if (work->ordered_func) { + spin_lock_irqsave(&wq->list_lock, flags); + list_add_tail(&work->ordered_list, &wq->ordered_list); + spin_unlock_irqrestore(&wq->list_lock, flags); + } + queue_work(wq->normal_wq, &work->normal_work); + trace_btrfs_work_queued(work); +} + +void btrfs_queue_work(struct btrfs_workqueue *wq, + struct btrfs_work *work) +{ + struct __btrfs_workqueue *dest_wq; + + if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags) && wq->high) + dest_wq = wq->high; + else + dest_wq = wq->normal; + __btrfs_queue_work(dest_wq, work); +} + +static inline void +__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq) +{ + destroy_workqueue(wq->normal_wq); + trace_btrfs_workqueue_destroy(wq); + kfree(wq); +} + +void btrfs_destroy_workqueue(struct btrfs_workqueue *wq) +{ + if (!wq) + return; + if (wq->high) + __btrfs_destroy_workqueue(wq->high); + __btrfs_destroy_workqueue(wq->normal); + kfree(wq); +} + +void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max) +{ + if (!wq) + return; + wq->normal->max_active = max; + if (wq->high) + wq->high->max_active = max; +} + +void btrfs_set_work_high_priority(struct btrfs_work *work) +{ + set_bit(WORK_HIGH_PRIO_BIT, &work->flags); +} |