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authorLai Jiangshan <jiangshanlai@gmail.com>2017-12-01 22:20:36 +0800
committerTejun Heo <tj@kernel.org>2017-12-04 14:44:11 -0800
commite8b3f8db7aad99fcc5234fc5b89984ff6620de3d (patch)
treea7b870b5b2899297c9a797b467919ae31bd581f4 /kernel
parentc98a9805096460567404799a7bd3149826affde7 (diff)
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')
-rw-r--r--kernel/workqueue.c15
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;
}