From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43417) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X73zO-00016K-0Z for qemu-devel@nongnu.org; Tue, 15 Jul 2014 10:46:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X73zF-0001Lt-Np for qemu-devel@nongnu.org; Tue, 15 Jul 2014 10:45:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:3562) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X73zF-0001Kh-0D for qemu-devel@nongnu.org; Tue, 15 Jul 2014 10:45:45 -0400 From: Stefan Hajnoczi Date: Tue, 15 Jul 2014 16:44:25 +0200 Message-Id: <1405435466-20801-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1405435466-20801-1-git-send-email-stefanha@redhat.com> References: <1405435466-20801-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH v2 1/2] thread-pool: avoid per-thread-pool EventNotifier List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paolo Bonzini , Christian Borntraeger EventNotifier is implemented using an eventfd or pipe. It therefore consumes file descriptors, which can be limited by rlimits and should therefore be used sparingly. Switch from EventNotifier to QEMUBH in thread-pool.c. Originally EventNotifier was used because qemu_bh_schedule() was not thread-safe yet. Reported-by: Christian Borntraeger Signed-off-by: Stefan Hajnoczi --- thread-pool.c | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-) diff --git a/thread-pool.c b/thread-pool.c index dfb699d..4cfd078 100644 --- a/thread-pool.c +++ b/thread-pool.c @@ -21,7 +21,6 @@ #include "block/coroutine.h" #include "trace.h" #include "block/block_int.h" -#include "qemu/event_notifier.h" #include "block/thread-pool.h" #include "qemu/main-loop.h" @@ -57,8 +56,8 @@ struct ThreadPoolElement { }; struct ThreadPool { - EventNotifier notifier; AioContext *ctx; + QEMUBH *completion_bh; QemuMutex lock; QemuCond check_cancel; QemuCond worker_stopped; @@ -119,7 +118,7 @@ static void *worker_thread(void *opaque) qemu_cond_broadcast(&pool->check_cancel); } - event_notifier_set(&pool->notifier); + qemu_bh_schedule(pool->completion_bh); } pool->cur_threads--; @@ -168,12 +167,11 @@ static void spawn_thread(ThreadPool *pool) } } -static void event_notifier_ready(EventNotifier *notifier) +static void thread_pool_completion_bh(void *opaque) { - ThreadPool *pool = container_of(notifier, ThreadPool, notifier); + ThreadPool *pool = opaque; ThreadPoolElement *elem, *next; - event_notifier_test_and_clear(notifier); restart: QLIST_FOREACH_SAFE(elem, &pool->head, all, next) { if (elem->state != THREAD_CANCELED && elem->state != THREAD_DONE) { @@ -215,7 +213,7 @@ static void thread_pool_cancel(BlockDriverAIOCB *acb) qemu_sem_timedwait(&pool->sem, 0) == 0) { QTAILQ_REMOVE(&pool->request_list, elem, reqs); elem->state = THREAD_CANCELED; - event_notifier_set(&pool->notifier); + qemu_bh_schedule(pool->completion_bh); } else { pool->pending_cancellations++; while (elem->state != THREAD_CANCELED && elem->state != THREAD_DONE) { @@ -224,7 +222,7 @@ static void thread_pool_cancel(BlockDriverAIOCB *acb) pool->pending_cancellations--; } qemu_mutex_unlock(&pool->lock); - event_notifier_ready(&pool->notifier); + thread_pool_completion_bh(pool); } static const AIOCBInfo thread_pool_aiocb_info = { @@ -293,8 +291,8 @@ static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx) } memset(pool, 0, sizeof(*pool)); - event_notifier_init(&pool->notifier, false); pool->ctx = ctx; + pool->completion_bh = aio_bh_new(ctx, thread_pool_completion_bh, pool); qemu_mutex_init(&pool->lock); qemu_cond_init(&pool->check_cancel); qemu_cond_init(&pool->worker_stopped); @@ -304,8 +302,6 @@ static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx) QLIST_INIT(&pool->head); QTAILQ_INIT(&pool->request_list); - - aio_set_event_notifier(ctx, &pool->notifier, event_notifier_ready); } ThreadPool *thread_pool_new(AioContext *ctx) @@ -339,11 +335,10 @@ void thread_pool_free(ThreadPool *pool) qemu_mutex_unlock(&pool->lock); - aio_set_event_notifier(pool->ctx, &pool->notifier, NULL); + qemu_bh_delete(pool->completion_bh); qemu_sem_destroy(&pool->sem); qemu_cond_destroy(&pool->check_cancel); qemu_cond_destroy(&pool->worker_stopped); qemu_mutex_destroy(&pool->lock); - event_notifier_cleanup(&pool->notifier); g_free(pool); } -- 1.9.3