diff options
| -rw-r--r-- | kernel/workqueue.c | 52 |
1 files changed, 47 insertions, 5 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 9508b5e..e38d035 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -4131,6 +4131,39 @@ static void rebind_workers(struct worker_pool *pool) spin_unlock_irq(&pool->lock); } +/** + * restore_unbound_workers_cpumask - restore cpumask of unbound workers + * @pool: unbound pool of interest + * @cpu: the CPU which is coming up + * + * An unbound pool may end up with a cpumask which doesn't have any online + * CPUs. When a worker of such pool get scheduled, the scheduler resets + * its cpus_allowed. If @cpu is in @pool's cpumask which didn't have any + * online CPU before, cpus_allowed of all its workers should be restored. + */ +static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu) +{ + static cpumask_t cpumask; + struct worker *worker; + int wi; + + lockdep_assert_held(&pool->manager_mutex); + + /* is @cpu allowed for @pool? */ + if (!cpumask_test_cpu(cpu, pool->attrs->cpumask)) + return; + + /* is @cpu the only online CPU? */ + cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask); + if (cpumask_weight(&cpumask) != 1) + return; + + /* as we're called from CPU_ONLINE, the following shouldn't fail */ + for_each_pool_worker(worker, wi, pool) + WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, + pool->attrs->cpumask) < 0); +} + /* * Workqueues should be brought up before normal priority CPU notifiers. * This will be registered high priority CPU notifier. @@ -4141,6 +4174,7 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, { int cpu = (unsigned long)hcpu; struct worker_pool *pool; + int pi; switch (action & ~CPU_TASKS_FROZEN) { case CPU_UP_PREPARE: @@ -4154,17 +4188,25 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, case CPU_DOWN_FAILED: case CPU_ONLINE: - for_each_cpu_worker_pool(pool, cpu) { + mutex_lock(&wq_mutex); + + for_each_pool(pool, pi) { mutex_lock(&pool->manager_mutex); - spin_lock_irq(&pool->lock); - pool->flags &= ~POOL_DISASSOCIATED; - spin_unlock_irq(&pool->lock); + if (pool->cpu == cpu) { + spin_lock_irq(&pool->lock); + pool->flags &= ~POOL_DISASSOCIATED; + spin_unlock_irq(&pool->lock); - rebind_workers(pool); + rebind_workers(pool); + } else if (pool->cpu < 0) { + restore_unbound_workers_cpumask(pool, cpu); + } mutex_unlock(&pool->manager_mutex); } + + mutex_unlock(&wq_mutex); break; } return NOTIFY_OK; |