From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60991) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XMhAN-0004Pb-S4 for qemu-devel@nongnu.org; Wed, 27 Aug 2014 13:38:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XMhAD-0003KF-7Y for qemu-devel@nongnu.org; Wed, 27 Aug 2014 13:37:51 -0400 Received: from e34.co.us.ibm.com ([32.97.110.152]:40569) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XMhAD-0003Jt-1S for qemu-devel@nongnu.org; Wed, 27 Aug 2014 13:37:41 -0400 Received: from /spool/local by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 27 Aug 2014 11:37:40 -0600 From: Michael Roth Date: Wed, 27 Aug 2014 12:36:21 -0500 Message-Id: <1409160982-16389-25-git-send-email-mdroth@linux.vnet.ibm.com> In-Reply-To: <1409160982-16389-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1409160982-16389-1-git-send-email-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 24/25] 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: qemu-stable@nongnu.org From: Stefan Hajnoczi 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 (cherry picked from commit c2e50e3d11a0bf4c973cc30478c1af0f2d5f8e81) Signed-off-by: Michael Roth --- 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); } -- 1.9.1