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| author | Tejun Heo <tj@kernel.org> | 2013-03-12 11:30:03 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-03-12 11:30:03 -0700 |
| commit | 493008a8e475771a2126e0ce95a73e35b371d277 (patch) | |
| tree | 0e67b51ade42bb623456aa186cec7a5722a8420c /kernel/workqueue.c | |
| parent | ac6104cdf87cc162b0a0d78280d1dcb9752e25bb (diff) | |
| download | lwn-493008a8e475771a2126e0ce95a73e35b371d277.tar.gz lwn-493008a8e475771a2126e0ce95a73e35b371d277.zip | |
workqueue: drop WQ_RESCUER and test workqueue->rescuer for NULL instead
WQ_RESCUER is superflous. WQ_MEM_RECLAIM indicates that the user
wants a rescuer and testing wq->rescuer for NULL can answer whether a
given workqueue has a rescuer or not. Drop WQ_RESCUER and test
wq->rescuer directly.
This will help simplifying __alloc_workqueue_key() failure path by
allowing it to use destroy_workqueue() on a partially constructed
workqueue, which in turn will help implementing dynamic management of
pool_workqueues.
While at it, clear wq->rescuer after freeing it in
destroy_workqueue(). This is a precaution as scheduled changes will
make destruction more complex.
This patch doesn't introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 22 |
1 files changed, 10 insertions, 12 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index a8b86f7b6e34..7ff2b9c5cc3a 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1827,7 +1827,7 @@ static void send_mayday(struct work_struct *work) lockdep_assert_held(&workqueue_lock); - if (!(wq->flags & WQ_RESCUER)) + if (!wq->rescuer) return; /* mayday mayday mayday */ @@ -2285,7 +2285,7 @@ sleep: * @__rescuer: self * * Workqueue rescuer thread function. There's one rescuer for each - * workqueue which has WQ_RESCUER set. + * workqueue which has WQ_MEM_RECLAIM set. * * Regular work processing on a pool may block trying to create a new * worker which uses GFP_KERNEL allocation which has slight chance of @@ -2769,7 +2769,7 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) * flusher is not running on the same workqueue by verifying write * access. */ - if (pwq->wq->saved_max_active == 1 || pwq->wq->flags & WQ_RESCUER) + if (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer) lock_map_acquire(&pwq->wq->lockdep_map); else lock_map_acquire_read(&pwq->wq->lockdep_map); @@ -3412,13 +3412,6 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, va_end(args); va_end(args1); - /* - * Workqueues which may be used during memory reclaim should - * have a rescuer to guarantee forward progress. - */ - if (flags & WQ_MEM_RECLAIM) - flags |= WQ_RESCUER; - max_active = max_active ?: WQ_DFL_ACTIVE; max_active = wq_clamp_max_active(max_active, flags, wq->name); @@ -3449,7 +3442,11 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, } local_irq_enable(); - if (flags & WQ_RESCUER) { + /* + * Workqueues which may be used during memory reclaim should + * have a rescuer to guarantee forward progress. + */ + if (flags & WQ_MEM_RECLAIM) { struct worker *rescuer; wq->rescuer = rescuer = alloc_worker(); @@ -3533,9 +3530,10 @@ void destroy_workqueue(struct workqueue_struct *wq) spin_unlock_irq(&workqueue_lock); - if (wq->flags & WQ_RESCUER) { + if (wq->rescuer) { kthread_stop(wq->rescuer->task); kfree(wq->rescuer); + wq->rescuer = NULL; } /* |