From f05b558d7e0368e0511a098c4beb9654e41246c4 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 3 Jun 2014 15:33:27 +0800 Subject: workqueue: clear POOL_DISASSOCIATED in rebind_workers() The commit a9ab775bcadf ("workqueue: directly restore CPU affinity of workers from CPU_ONLINE") moved the pool->lock into rebind_workers() without also moving "pool->flags &= ~POOL_DISASSOCIATED". There is nothing wrong with "pool->flags &= ~POOL_DISASSOCIATED" not being moved together, but there isn't any benefit either. We move it into rebind_workers() and achieve these benefits: 1) Better readability. POOL_DISASSOCIATED is cleared in rebind_workers() as expected. 2) When POOL_DISASSOCIATED is cleared, we can ensure that all the running workers of the pool are on the local CPU (pool->cpu). tj: Cosmetic updates to the code and description. Signed-off-by: Lai Jiangshan Signed-off-by: Tejun Heo --- kernel/workqueue.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) (limited to 'kernel/workqueue.c') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 6203d2900877..129e4c3452ee 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -4542,6 +4542,7 @@ static void rebind_workers(struct worker_pool *pool) pool->attrs->cpumask) < 0); spin_lock_irq(&pool->lock); + pool->flags &= ~POOL_DISASSOCIATED; for_each_pool_worker(worker, pool) { unsigned int worker_flags = worker->flags; @@ -4643,15 +4644,10 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb, for_each_pool(pool, pi) { mutex_lock(&pool->attach_mutex); - if (pool->cpu == cpu) { - spin_lock_irq(&pool->lock); - pool->flags &= ~POOL_DISASSOCIATED; - spin_unlock_irq(&pool->lock); - + if (pool->cpu == cpu) rebind_workers(pool); - } else if (pool->cpu < 0) { + else if (pool->cpu < 0) restore_unbound_workers_cpumask(pool, cpu); - } mutex_unlock(&pool->attach_mutex); } -- cgit v1.2.3-58-ga151 From 807407c0a29b1e9fe35565f5a671ef3a9dd9f00c Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 3 Jun 2014 15:33:28 +0800 Subject: workqueue: stronger test in process_one_work() After the recent changes, when POOL_DISASSOCIATED is cleared, the running worker's local CPU should be the same as pool->cpu without any exception even during cpu-hotplug. Update the sanity check in process_one_work() accordingly. This patch changes "(proposition_A && proposition_B && proposition_C)" to "(proposition_B && proposition_C)", so if the old compound proposition is true, the new one must be true too. so this will not hide any possible bug which can be caught by the old test. tj: Minor updates to the description. CC: Jason J. Herne CC: Sasha Levin Signed-off-by: Lai Jiangshan Signed-off-by: Tejun Heo --- kernel/workqueue.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) (limited to 'kernel/workqueue.c') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 129e4c3452ee..a3021d63f62d 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2020,13 +2020,8 @@ __acquires(&pool->lock) lockdep_copy_map(&lockdep_map, &work->lockdep_map); #endif - /* - * Ensure we're on the correct CPU. DISASSOCIATED test is - * necessary to avoid spurious warnings from rescuers servicing the - * unbound or a disassociated pool. - */ - WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) && - !(pool->flags & POOL_DISASSOCIATED) && + /* ensure we're on the correct CPU */ + WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) && raw_smp_processor_id() != pool->cpu); /* -- cgit v1.2.3-58-ga151