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| author | Lai Jiangshan <jiangshanlai@gmail.com> | 2017-12-01 22:20:36 +0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2017-12-04 14:44:11 -0800 |
| commit | e8b3f8db7aad99fcc5234fc5b89984ff6620de3d (patch) | |
| tree | a7b870b5b2899297c9a797b467919ae31bd581f4 /kernel/workqueue.c | |
| parent | c98a9805096460567404799a7bd3149826affde7 (diff) | |
| download | lwn-e8b3f8db7aad99fcc5234fc5b89984ff6620de3d.tar.gz lwn-e8b3f8db7aad99fcc5234fc5b89984ff6620de3d.zip | |
workqueue/hotplug: simplify workqueue_offline_cpu()
Since the recent cpu/hotplug refactoring, workqueue_offline_cpu() is
guaranteed to run on the local cpu which is going offline.
This also fixes the following deadlock by removing work item
scheduling and flushing from CPU hotplug path.
http://lkml.kernel.org/r/1504764252-29091-1-git-send-email-prsood@codeaurora.org
tj: Description update.
Signed-off-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 6a5658cb46da..48a4d00f55dc 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1635,7 +1635,7 @@ static void worker_enter_idle(struct worker *worker) mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT); /* - * Sanity check nr_running. Because wq_unbind_fn() releases + * Sanity check nr_running. Because unbind_workers() releases * pool->lock between setting %WORKER_UNBOUND and zapping * nr_running, the warning may trigger spuriously. Check iff * unbind is not in progress. @@ -4511,9 +4511,8 @@ void show_workqueue_state(void) * cpu comes back online. */ -static void wq_unbind_fn(struct work_struct *work) +static void unbind_workers(int cpu) { - int cpu = smp_processor_id(); struct worker_pool *pool; struct worker *worker; @@ -4710,12 +4709,13 @@ int workqueue_online_cpu(unsigned int cpu) int workqueue_offline_cpu(unsigned int cpu) { - struct work_struct unbind_work; struct workqueue_struct *wq; /* unbinding per-cpu workers should happen on the local CPU */ - INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn); - queue_work_on(cpu, system_highpri_wq, &unbind_work); + if (WARN_ON(cpu != smp_processor_id())) + return -1; + + unbind_workers(cpu); /* update NUMA affinity of unbound workqueues */ mutex_lock(&wq_pool_mutex); @@ -4723,9 +4723,6 @@ int workqueue_offline_cpu(unsigned int cpu) wq_update_unbound_numa(wq, cpu, false); mutex_unlock(&wq_pool_mutex); - /* wait for per-cpu unbinding to finish */ - flush_work(&unbind_work); - destroy_work_on_stack(&unbind_work); return 0; } |