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From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Tejun Heo <tj@kernel.org>, linux-kernel@vger.kernel.org
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Subject: [PATCH 10/10 V4] workqueue: merge the role of rebind_hold to idle_done
Date: Sun, 2 Sep 2012 00:28:28 +0800	[thread overview]
Message-ID: <1346516916-1991-11-git-send-email-laijs@cn.fujitsu.com> (raw)
In-Reply-To: <1346516916-1991-1-git-send-email-laijs@cn.fujitsu.com>

Currently is single pass, we can wait on idle_done instead wait on rebind_hold.
So we can remove rebind_hold and make the code simpler.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
 kernel/workqueue.c |   35 +++++++++++------------------------
 1 files changed, 11 insertions(+), 24 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 6d68571..6411616 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1309,9 +1309,6 @@ struct idle_rebind {
 	int		  idle_cnt;	/* # idle workers to be rebound */
 	struct completion idle_done;	/* all idle workers rebound */
 
-	/* idle workers wait all idles to be rebound */
-	struct completion rebind_hold;
-
 	/*
 	 * notify the rebind_workers() that:
 	 * 1. All idle workers are rebound.
@@ -1340,7 +1337,7 @@ static void synchronize_all_idles_rebound(struct global_cwq *gcwq,
 {
 
 	/* wait for rebind_workers() to notify that all idles are rebound */
-	wait_for_completion(&idle_rebind->rebind_hold);
+	wait_for_completion(&idle_rebind->idle_done);
 
 	/* finished synchronizing, put reference */
 	spin_lock_irq(&gcwq->lock);
@@ -1371,7 +1368,7 @@ static void idle_worker_rebind(struct worker *worker)
 
 	/* this worker has been rebound */
 	if (!--idle_rebind->idle_cnt)
-		complete(&idle_rebind->idle_done);
+		complete_all(&idle_rebind->idle_done);
 	spin_unlock_irq(&gcwq->lock);
 
 	synchronize_all_idles_rebound(gcwq, idle_rebind);
@@ -1447,17 +1444,15 @@ static void rebind_workers(struct global_cwq *gcwq)
 		lockdep_assert_held(&pool->manager_mutex);
 
 	/*
-	 * Rebind idle workers.  Interlocked both ways in triple waits.
-	 * We wait for workers to rebind via @idle_rebind.idle_done.
-	 * Workers will wait for us via @idle_rebind.rebind_hold.
-	 * And them we wait for workers to leave rebind_hold
-	 * via @idle_rebind.ref_done.
+	 * Rebind idle workers. Idle workers wait each other to rebind via
+	 * synchronize_all_idles_rebound(). We wait for all idle workers
+	 * to rebind via synchronize_all_idles_rebound() too.
+	 * And them we wait for all workers finish synchronizing and
+	 * release the ref of @idle_rebind via @idle_rebind.ref_done.
 	 */
 	init_completion(&idle_rebind.idle_done);
-	init_completion(&idle_rebind.rebind_hold);
 	init_completion(&idle_rebind.ref_done);
 	idle_rebind.ref_cnt = 1;
-	gcwq->idle_rebind = &idle_rebind;
 	idle_rebind.idle_cnt = 1;
 
 	/* set REBIND and kick idle ones, we'll wait for these later */
@@ -1497,23 +1492,15 @@ static void rebind_workers(struct global_cwq *gcwq)
 	}
 
 	/*
-	 * we will leave rebind_workers(), have to wait until no worker
-	 * has ref to this idle_rebind.
+	 * we will leave rebind_workers(), have to wait until all idles
+	 * are rebound and until no worker has ref to this idle_rebind.
 	 */
 	if (--idle_rebind.idle_cnt) {
+		gcwq->idle_rebind = &idle_rebind;
 		spin_unlock_irq(&gcwq->lock);
-		wait_for_completion(&idle_rebind.idle_done);
-		spin_lock_irq(&gcwq->lock);
-	}
-
-	complete_all(&idle_rebind.rebind_hold);
-
-	if (--idle_rebind.ref_cnt) {
-		spin_unlock_irq(&gcwq->lock);
+		synchronize_all_idles_rebound(gcwq, &idle_rebind);
 		wait_for_completion(&idle_rebind.ref_done);
 		spin_lock_irq(&gcwq->lock);
-	} else {
-		gcwq->idle_rebind = NULL;
 	}
 }
 
-- 
1.7.4.4


  parent reply	other threads:[~2012-09-01 17:45 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-01 16:28 [PATCH 00/10 V4] workqueue: fix and cleanup hotplug/rebind_workers() Lai Jiangshan
2012-09-01 16:28 ` [PATCH 01/10 V4] workqueue: ensure the wq_worker_sleeping() see the right flags Lai Jiangshan
2012-09-04 23:39   ` [PATCH] workqueue: UNBOUND -> REBIND morphing in rebind_workers() should be atomic Tejun Heo
2012-09-04 23:58     ` [PATCH -stable] " Tejun Heo
2012-09-16 15:49       ` Ben Hutchings
2012-09-05  1:05     ` [PATCH] " Lai Jiangshan
2012-09-05  1:17       ` Tejun Heo
2012-09-01 16:28 ` [PATCH 02/10 V4] workqueue: fix deadlock in rebind_workers() Lai Jiangshan
2012-09-05  0:54   ` Tejun Heo
2012-09-05  1:28     ` Lai Jiangshan
2012-09-05  1:33       ` Tejun Heo
2012-09-01 16:28 ` [PATCH 03/10 V4] workqueue: add POOL_MANAGING_WORKERS Lai Jiangshan
2012-09-01 16:28 ` [PATCH 04/10 V4] workqueue: add manage_workers_slowpath() Lai Jiangshan
2012-09-05  1:12   ` Tejun Heo
2012-09-06  1:55     ` Lai Jiangshan
2012-09-01 16:28 ` [PATCH 05/10 V4] workqueue: move rebind_hold to idle_rebind Lai Jiangshan
2012-09-01 16:28 ` [PATCH 06/10 V4] workqueue: simple clear WORKER_REBIND Lai Jiangshan
2012-09-01 16:28 ` [PATCH 07/10 V4] workqueue: move idle_rebind pointer to gcwq Lai Jiangshan
2012-09-01 16:28 ` [PATCH 08/10 V4] workqueue: explicit way to wait for idles workers to finish Lai Jiangshan
2012-09-01 16:28 ` [PATCH 09/10] workqueue: single pass rebind_workers Lai Jiangshan
2012-09-01 16:28 ` Lai Jiangshan [this message]
2012-09-05  1:15   ` [PATCH 10/10 V4] workqueue: merge the role of rebind_hold to idle_done Tejun Heo
2012-09-05  1:48     ` Lai Jiangshan

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