From 5c25b5ff89f004c30b04759dc34ace8585a4085f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 12 Jan 2021 11:26:49 +0100 Subject: workqueue: Tag bound workers with KTHREAD_IS_PER_CPU Mark the per-cpu workqueue workers as KTHREAD_IS_PER_CPU. Workqueues have unfortunate semantics in that per-cpu workers are not default flushed and parked during hotplug, however a subset does manual flush on hotplug and hard relies on them for correctness. Therefore play silly games.. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Tested-by: Valentin Schneider Link: https://lkml.kernel.org/r/20210121103506.693465814@infradead.org --- kernel/workqueue.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'kernel/workqueue.c') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 1646331546eb..cce34336fbd7 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1861,6 +1861,8 @@ static void worker_attach_to_pool(struct worker *worker, */ if (pool->flags & POOL_DISASSOCIATED) worker->flags |= WORKER_UNBOUND; + else + kthread_set_per_cpu(worker->task, pool->cpu); list_add_tail(&worker->node, &pool->workers); worker->pool = pool; @@ -1883,6 +1885,7 @@ static void worker_detach_from_pool(struct worker *worker) mutex_lock(&wq_pool_attach_mutex); + kthread_set_per_cpu(worker->task, -1); list_del(&worker->node); worker->pool = NULL; @@ -4919,8 +4922,10 @@ static void unbind_workers(int cpu) raw_spin_unlock_irq(&pool->lock); - for_each_pool_worker(worker, pool) + for_each_pool_worker(worker, pool) { + kthread_set_per_cpu(worker->task, -1); WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0); + } mutex_unlock(&wq_pool_attach_mutex); @@ -4972,9 +4977,11 @@ static void rebind_workers(struct worker_pool *pool) * of all workers first and then clear UNBOUND. As we're called * from CPU_ONLINE, the following shouldn't fail. */ - for_each_pool_worker(worker, pool) + for_each_pool_worker(worker, pool) { + kthread_set_per_cpu(worker->task, pool->cpu); WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask) < 0); + } raw_spin_lock_irq(&pool->lock); -- cgit v1.2.3-59-g8ed1b