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Btrfs: keep irqs on more often in the worker threads

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The btrfs worker thread spinlock was being used both for the
queueing of IO and for the processing of ordered events.

The ordered events never happen from end_io handlers, and so they
don't need to use the _irq version of spinlocks.  This adds a
dedicated lock to the ordered lists so they don't have to run
with irqs off.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2009-08-05 16:36:45 -04:00
parent 40431d6c12
commit 4e3f9c5042
2 changed files with 16 additions and 10 deletions
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23
fs/btrfs/async-thread.c
View file

@ -124,14 +124,12 @@ out:
static noinline int run_ordered_completions(struct btrfs_workers *workers,
struct btrfs_work *work)
{
unsigned long flags;
if (!workers->ordered)
return 0;
set_bit(WORK_DONE_BIT, &work->flags);
spin_lock_irqsave(&workers->lock, flags);
spin_lock(&workers->order_lock);
while (1) {
if (!list_empty(&workers->prio_order_list)) {
@ -154,17 +152,17 @@ static noinline int run_ordered_completions(struct btrfs_workers *workers,
if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
break;
spin_unlock_irqrestore(&workers->lock, flags);
spin_unlock(&workers->order_lock);
work->ordered_func(work);
/* now take the lock again and call the freeing code */
spin_lock_irqsave(&workers->lock, flags);
spin_lock(&workers->order_lock);
list_del(&work->order_list);
work->ordered_free(work);
}
spin_unlock_irqrestore(&workers->lock, flags);
spin_unlock(&workers->order_lock);
return 0;
}
@ -345,6 +343,7 @@ void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max)
INIT_LIST_HEAD(&workers->order_list);
INIT_LIST_HEAD(&workers->prio_order_list);
spin_lock_init(&workers->lock);
spin_lock_init(&workers->order_lock);
workers->max_workers = max;
workers->idle_thresh = 32;
workers->name = name;
@ -374,6 +373,7 @@ int btrfs_start_workers(struct btrfs_workers *workers, int num_workers)
INIT_LIST_HEAD(&worker->prio_pending);
INIT_LIST_HEAD(&worker->worker_list);
spin_lock_init(&worker->lock);
atomic_set(&worker->num_pending, 0);
atomic_set(&worker->refs, 1);
worker->workers = workers;
@ -453,10 +453,8 @@ static struct btrfs_worker_thread *find_worker(struct btrfs_workers *workers)
again:
spin_lock_irqsave(&workers->lock, flags);
worker = next_worker(workers);
spin_unlock_irqrestore(&workers->lock, flags);
if (!worker) {
spin_lock_irqsave(&workers->lock, flags);
if (workers->num_workers >= workers->max_workers) {
goto fallback;
} else if (workers->atomic_worker_start) {
@ -469,6 +467,7 @@ again:
goto again;
}
}
spin_unlock_irqrestore(&workers->lock, flags);
return worker;
fallback:
@ -552,14 +551,18 @@ int btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
worker = find_worker(workers);
if (workers->ordered) {
spin_lock_irqsave(&workers->lock, flags);
/*
* you're not allowed to do ordered queues from an
* interrupt handler
*/
spin_lock(&workers->order_lock);
if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags)) {
list_add_tail(&work->order_list,
&workers->prio_order_list);
} else {
list_add_tail(&work->order_list, &workers->order_list);
}
spin_unlock_irqrestore(&workers->lock, flags);
spin_unlock(&workers->order_lock);
} else {
INIT_LIST_HEAD(&work->order_list);
}

3
fs/btrfs/async-thread.h
View file

@ -99,6 +99,9 @@ struct btrfs_workers {
/* lock for finding the next worker thread to queue on */
spinlock_t lock;
/* lock for the ordered lists */
spinlock_t order_lock;
/* extra name for this worker, used for current->name */
char *name;
};