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author | Chris Mason <chris.mason@oracle.com> | 2009-08-07 13:27:38 (GMT) |
---|---|---|
committer | Chris Mason <chris.mason@oracle.com> | 2009-09-11 17:31:04 (GMT) |
commit | 4f878e8475a465ddbd951e06a23317303f1b5b30 (patch) | |
tree | 7e1811794d3f6eaf455a3e26afd49ba06a0db554 /fs/btrfs/async-thread.c | |
parent | 4e3f9c5042b43301d70781aee4a164a20878066b (diff) | |
download | linux-fsl-qoriq-4f878e8475a465ddbd951e06a23317303f1b5b30.tar.xz |
Btrfs: reduce worker thread spin_lock_irq hold times
This changes the btrfs worker threads to batch work items
into a local list. It allows us to pull work items in
large chunks and significantly reduces the number of times we
need to take the worker thread spinlock.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/async-thread.c')
-rw-r--r-- | fs/btrfs/async-thread.c | 74 |
1 files changed, 60 insertions, 14 deletions
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c index 4b4372d..6ea5cd0 100644 --- a/fs/btrfs/async-thread.c +++ b/fs/btrfs/async-thread.c @@ -196,31 +196,73 @@ static int try_worker_shutdown(struct btrfs_worker_thread *worker) return freeit; } +static struct btrfs_work *get_next_work(struct btrfs_worker_thread *worker, + struct list_head *prio_head, + struct list_head *head) +{ + struct btrfs_work *work = NULL; + struct list_head *cur = NULL; + + if(!list_empty(prio_head)) + cur = prio_head->next; + + smp_mb(); + if (!list_empty(&worker->prio_pending)) + goto refill; + + if (!list_empty(head)) + cur = head->next; + + if (cur) + goto out; + +refill: + spin_lock_irq(&worker->lock); + list_splice_tail_init(&worker->prio_pending, prio_head); + list_splice_tail_init(&worker->pending, head); + + if (!list_empty(prio_head)) + cur = prio_head->next; + else if (!list_empty(head)) + cur = head->next; + spin_unlock_irq(&worker->lock); + + if (!cur) + goto out_fail; + +out: + work = list_entry(cur, struct btrfs_work, list); + +out_fail: + return work; +} + /* * main loop for servicing work items */ static int worker_loop(void *arg) { struct btrfs_worker_thread *worker = arg; - struct list_head *cur; + struct list_head head; + struct list_head prio_head; struct btrfs_work *work; + + INIT_LIST_HEAD(&head); + INIT_LIST_HEAD(&prio_head); + do { - spin_lock_irq(&worker->lock); -again_locked: +again: while (1) { - if (!list_empty(&worker->prio_pending)) - cur = worker->prio_pending.next; - else if (!list_empty(&worker->pending)) - cur = worker->pending.next; - else + + + work = get_next_work(worker, &prio_head, &head); + if (!work) break; - work = list_entry(cur, struct btrfs_work, list); list_del(&work->list); clear_bit(WORK_QUEUED_BIT, &work->flags); work->worker = worker; - spin_unlock_irq(&worker->lock); work->func(work); @@ -233,9 +275,11 @@ again_locked: check_pending_worker_creates(worker); - spin_lock_irq(&worker->lock); - check_idle_worker(worker); } + + spin_lock_irq(&worker->lock); + check_idle_worker(worker); + if (freezing(current)) { worker->working = 0; spin_unlock_irq(&worker->lock); @@ -274,8 +318,10 @@ again_locked: spin_lock_irq(&worker->lock); set_current_state(TASK_INTERRUPTIBLE); if (!list_empty(&worker->pending) || - !list_empty(&worker->prio_pending)) - goto again_locked; + !list_empty(&worker->prio_pending)) { + spin_unlock_irq(&worker->lock); + goto again; + } /* * this makes sure we get a wakeup when someone |