From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932081Ab2IJCJi (ORCPT ); Sun, 9 Sep 2012 22:09:38 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:58940 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1756352Ab2IJCJg (ORCPT ); Sun, 9 Sep 2012 22:09:36 -0400 X-IronPort-AV: E=Sophos;i="4.80,396,1344182400"; d="scan'208";a="5810270" From: Lai Jiangshan To: Tejun Heo , linux-kernel@vger.kernel.org Cc: Lai Jiangshan Subject: [PATCH 1/2 V7 for-3.6-fixes] workqueue: add POOL_MANAGING_WORKERS Date: Mon, 10 Sep 2012 10:11:24 +0800 Message-Id: <1347243085-2510-1-git-send-email-laijs@cn.fujitsu.com> X-Mailer: git-send-email 1.7.4.4 X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/09/10 10:09:04, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/09/10 10:09:05, Serialize complete at 2012/09/10 10:09:05 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When hotplug happens, the plug code will also grab the manager_mutex, it will break too_many_workers()'s assumption, and make too_many_workers() ugly(kick the timer wrongly, no found bug). To avoid assumption-coruption, we add the original POOL_MANAGING_WORKERS back. Signed-off-by: Lai Jiangshan --- kernel/workqueue.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index dc7b845..383548e 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -66,6 +66,7 @@ enum { /* pool flags */ POOL_MANAGE_WORKERS = 1 << 0, /* need to manage workers */ + POOL_MANAGING_WORKERS = 1 << 1, /* managing workers */ /* worker flags */ WORKER_STARTED = 1 << 0, /* started */ @@ -652,7 +653,7 @@ static bool need_to_manage_workers(struct worker_pool *pool) /* Do we have too many workers and should some go away? */ static bool too_many_workers(struct worker_pool *pool) { - bool managing = mutex_is_locked(&pool->manager_mutex); + bool managing = pool->flags & POOL_MANAGING_WORKERS; int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ int nr_busy = pool->nr_workers - nr_idle; @@ -1827,6 +1828,7 @@ static bool manage_workers(struct worker *worker) if (!mutex_trylock(&pool->manager_mutex)) return ret; + pool->flags |= POOL_MANAGING_WORKERS; pool->flags &= ~POOL_MANAGE_WORKERS; /* @@ -1836,6 +1838,7 @@ static bool manage_workers(struct worker *worker) ret |= maybe_destroy_workers(pool); ret |= maybe_create_worker(pool); + pool->flags &= ~POOL_MANAGING_WORKERS; mutex_unlock(&pool->manager_mutex); return ret; } -- 1.7.4.4