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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-03-18 18:47:07 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-03-18 18:47:07 -0700 |
commit | b63dc123b20e54a306ff1bfa191e511c506ee331 (patch) | |
tree | ab7b2b9259bbb1bf9c139e71b94cdfd27c69a9f8 /kernel/workqueue.c | |
parent | 35f8c769aa5f3d9a81d50e9bdcbfd4151e72a0c9 (diff) | |
parent | eb2834285cf172856cd12f66892fc7467935ebed (diff) | |
download | op-kernel-dev-b63dc123b20e54a306ff1bfa191e511c506ee331.zip op-kernel-dev-b63dc123b20e54a306ff1bfa191e511c506ee331.tar.gz |
Merge branch 'for-3.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
"Lai's patch to fix highly unlikely but still possible workqueue stall
during CPU hotunplug."
* 'for-3.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix possible pool stall bug in wq_unbind_fn()
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r-- | kernel/workqueue.c | 44 |
1 files changed, 25 insertions, 19 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 55fac5b..b48cd59 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3447,28 +3447,34 @@ static void wq_unbind_fn(struct work_struct *work) spin_unlock_irq(&pool->lock); mutex_unlock(&pool->assoc_mutex); - } - /* - * Call schedule() so that we cross rq->lock and thus can guarantee - * sched callbacks see the %WORKER_UNBOUND flag. This is necessary - * as scheduler callbacks may be invoked from other cpus. - */ - schedule(); + /* + * Call schedule() so that we cross rq->lock and thus can + * guarantee sched callbacks see the %WORKER_UNBOUND flag. + * This is necessary as scheduler callbacks may be invoked + * from other cpus. + */ + schedule(); - /* - * Sched callbacks are disabled now. Zap nr_running. After this, - * nr_running stays zero and need_more_worker() and keep_working() - * are always true as long as the worklist is not empty. Pools on - * @cpu now behave as unbound (in terms of concurrency management) - * pools which are served by workers tied to the CPU. - * - * On return from this function, the current worker would trigger - * unbound chain execution of pending work items if other workers - * didn't already. - */ - for_each_std_worker_pool(pool, cpu) + /* + * Sched callbacks are disabled now. Zap nr_running. + * After this, nr_running stays zero and need_more_worker() + * and keep_working() are always true as long as the + * worklist is not empty. This pool now behaves as an + * unbound (in terms of concurrency management) pool which + * are served by workers tied to the pool. + */ atomic_set(&pool->nr_running, 0); + + /* + * With concurrency management just turned off, a busy + * worker blocking could lead to lengthy stalls. Kick off + * unbound chain execution of currently pending work items. + */ + spin_lock_irq(&pool->lock); + wake_up_worker(pool); + spin_unlock_irq(&pool->lock); + } } /* |