Since destroy_worker() is working atomically, we move maybe_destroy_worker() out from manager and destroy worker directly in idle timeout handler. And we remove %POOL_MANAGE_WORKERS which help us remove a branch in worker_thread().
Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com> --- kernel/workqueue.c | 71 ++++----------------------------------------------- 1 files changed, 6 insertions(+), 65 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 8199e7f..92c9ada 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -64,7 +64,6 @@ enum { * %WORKER_UNBOUND set and concurrency management disabled, and may * be executing on any CPU. The pool behaves as an unbound one. */ - POOL_MANAGE_WORKERS = 1 << 0, /* need to manage workers */ POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */ /* worker flags */ @@ -754,13 +753,6 @@ static bool need_to_create_worker(struct worker_pool *pool) return need_more_worker(pool) && !may_start_working(pool); } -/* Do I need to be the manager? */ -static bool need_to_manage_workers(struct worker_pool *pool) -{ - return need_to_create_worker(pool) || - (pool->flags & POOL_MANAGE_WORKERS); -} - /* Do we have too many workers and should some go away? */ static bool too_many_workers(struct worker_pool *pool) { @@ -1789,7 +1781,7 @@ static int create_and_start_worker(struct worker_pool *pool) * Destroy @worker and adjust @pool stats accordingly. * * CONTEXT: - * spin_lock_irq(pool->lock) which is released and regrabbed. + * spin_lock_irq(pool->lock). */ static void destroy_worker(struct worker *worker) { @@ -1819,8 +1811,7 @@ static void idle_worker_timeout(unsigned long __pool) struct worker_pool *pool = (void *)__pool; spin_lock_irq(&pool->lock); - - if (too_many_workers(pool)) { + while (too_many_workers(pool)) { struct worker *worker; unsigned long expires; @@ -1828,15 +1819,13 @@ static void idle_worker_timeout(unsigned long __pool) worker = list_entry(pool->idle_list.prev, struct worker, entry); expires = worker->last_active + IDLE_WORKER_TIMEOUT; - if (time_before(jiffies, expires)) + if (time_before(jiffies, expires)) { mod_timer(&pool->idle_timer, expires); - else { - /* it's been idle for too long, wake up manager */ - pool->flags |= POOL_MANAGE_WORKERS; - wake_up_worker(pool); + break; } - } + destroy_worker(worker); + } spin_unlock_irq(&pool->lock); } @@ -1960,44 +1949,6 @@ restart: } /** - * maybe_destroy_worker - destroy workers which have been idle for a while - * @pool: pool to destroy workers for - * - * Destroy @pool workers which have been idle for longer than - * IDLE_WORKER_TIMEOUT. - * - * LOCKING: - * spin_lock_irq(pool->lock) which may be released and regrabbed - * multiple times. Called only from manager. - * - * Return: - * %false if no action was taken and pool->lock stayed locked, %true - * otherwise. - */ -static bool maybe_destroy_workers(struct worker_pool *pool) -{ - bool ret = false; - - while (too_many_workers(pool)) { - struct worker *worker; - unsigned long expires; - - worker = list_entry(pool->idle_list.prev, struct worker, entry); - expires = worker->last_active + IDLE_WORKER_TIMEOUT; - - if (time_before(jiffies, expires)) { - mod_timer(&pool->idle_timer, expires); - break; - } - - destroy_worker(worker); - ret = true; - } - - return ret; -} - -/** * manage_workers - manage worker pool * @worker: self * @@ -2039,13 +1990,6 @@ static bool manage_workers(struct worker *worker) if (!mutex_trylock(&pool->manager_arb)) return ret; - pool->flags &= ~POOL_MANAGE_WORKERS; - - /* - * Destroy and then create so that may_start_working() is true - * on return. - */ - ret |= maybe_destroy_workers(pool); ret |= maybe_create_worker(pool); mutex_unlock(&pool->manager_arb); @@ -2285,9 +2229,6 @@ recheck: worker_set_flags(worker, WORKER_PREP, false); sleep: - if (unlikely(need_to_manage_workers(pool)) && manage_workers(worker)) - goto recheck; - /* * pool->lock is held and there's no work to process and no need to * manage, sleep. Workers are woken up only while holding -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/