diff options
| -rw-r--r-- | kernel/workqueue.c | 74 |
1 files changed, 8 insertions, 66 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b1de6ac..6603923 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1603,70 +1603,6 @@ static void worker_leave_idle(struct worker *worker) list_del_init(&worker->entry); } -/** - * worker_maybe_bind_and_lock - try to bind %current to worker_pool and lock it - * @pool: target worker_pool - * - * Bind %current to the cpu of @pool if it is associated and lock @pool. - * - * Works which are scheduled while the cpu is online must at least be - * scheduled to a worker which is bound to the cpu so that if they are - * flushed from cpu callbacks while cpu is going down, they are - * guaranteed to execute on the cpu. - * - * This function is to be used by unbound workers and rescuers to bind - * themselves to the target cpu and may race with cpu going down or - * coming online. kthread_bind() can't be used because it may put the - * worker to already dead cpu and set_cpus_allowed_ptr() can't be used - * verbatim as it's best effort and blocking and pool may be - * [dis]associated in the meantime. - * - * This function tries set_cpus_allowed() and locks pool and verifies the - * binding against %POOL_DISASSOCIATED which is set during - * %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker - * enters idle state or fetches works without dropping lock, it can - * guarantee the scheduling requirement described in the first paragraph. - * - * CONTEXT: - * Might sleep. Called without any lock but returns with pool->lock - * held. - * - * Return: - * %true if the associated pool is online (@worker is successfully - * bound), %false if offline. - */ -static bool worker_maybe_bind_and_lock(struct worker_pool *pool) -__acquires(&pool->lock) -{ - while (true) { - /* - * The following call may fail, succeed or succeed - * without actually migrating the task to the cpu if - * it races with cpu hotunplug operation. Verify - * against POOL_DISASSOCIATED. - */ - if (!(pool->flags & POOL_DISASSOCIATED)) - set_cpus_allowed_ptr(current, pool->attrs->cpumask); - - spin_lock_irq(&pool->lock); - if (pool->flags & POOL_DISASSOCIATED) - return false; - if (task_cpu(current) == pool->cpu && - cpumask_equal(¤t->cpus_allowed, pool->attrs->cpumask)) - return true; - spin_unlock_irq(&pool->lock); - - /* - * We've raced with CPU hot[un]plug. Give it a breather - * and retry migration. cond_resched() is required here; - * otherwise, we might deadlock against cpu_stop trying to - * bring down the CPU on non-preemptive kernel. - */ - cpu_relax(); - cond_resched(); - } -} - static struct worker *alloc_worker(void) { struct worker *worker; @@ -2361,8 +2297,9 @@ repeat: spin_unlock_irq(&wq_mayday_lock); - /* migrate to the target cpu if possible */ - worker_maybe_bind_and_lock(pool); + worker_attach_to_pool(rescuer, pool); + + spin_lock_irq(&pool->lock); rescuer->pool = pool; /* @@ -2375,6 +2312,11 @@ repeat: move_linked_works(work, scheduled, &n); process_scheduled_works(rescuer); + spin_unlock_irq(&pool->lock); + + worker_detach_from_pool(rescuer, pool); + + spin_lock_irq(&pool->lock); /* * Put the reference grabbed by send_mayday(). @pool won't |