From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759747Ab2IFUH3 (ORCPT ); Thu, 6 Sep 2012 16:07:29 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:47570 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758080Ab2IFUH1 (ORCPT ); Thu, 6 Sep 2012 16:07:27 -0400 Date: Thu, 6 Sep 2012 13:07:23 -0700 From: Tejun Heo To: linux-kernel@vger.kernel.org, Lai Jiangshan Subject: [PATCH wq/for-3.6-fixes 2/3] workqueue: rename rebind_workers() to gcwq_associate() and let it handle locking and DISASSOCIATED clearing Message-ID: <20120906200723.GH29092@google.com> References: <20120906200647.GG29092@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120906200647.GG29092@google.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>From 0150a04271dbcc9abbb2575911fa1d72d40451bf Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 6 Sep 2012 12:50:40 -0700 CPU_ONLINE used to handle locking and clearing of DISASSOCIATED and rebind_workers() just the rebinding. This patch renames the function to gcwq_associate() and let it handle the whole onlining. This is for the scheduled fix of a subtle idle worker depletion issue during CPU_ONLINE. Note that this removes the unnecessary relock at the end of gcwq_associate(). This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo --- kernel/workqueue.c | 29 ++++++++++++++--------------- 1 files changed, 14 insertions(+), 15 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 63ede1f..b19170b 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -480,6 +480,8 @@ static atomic_t unbound_pool_nr_running[NR_WORKER_POOLS] = { }; static int worker_thread(void *__worker); +static void gcwq_claim_management(struct global_cwq *gcwq); +static void gcwq_release_management(struct global_cwq *gcwq); static int worker_pool_pri(struct worker_pool *pool) { @@ -1355,11 +1357,11 @@ static void busy_worker_rebind_fn(struct work_struct *work) } /** - * rebind_workers - rebind all workers of a gcwq to the associated CPU + * gcwq_associate - (re)associate a gcwq to its CPU and rebind its workers * @gcwq: gcwq of interest * - * @gcwq->cpu is coming online. Rebind all workers to the CPU. Rebinding - * is different for idle and busy ones. + * @gcwq->cpu is coming online. Clear %GCWQ_DISASSOCIATED and rebind all + * workers to the CPU. Rebinding is different for idle and busy ones. * * The idle ones should be rebound synchronously and idle rebinding should * be complete before any worker starts executing work items with @@ -1378,8 +1380,7 @@ static void busy_worker_rebind_fn(struct work_struct *work) * On return, all workers are guaranteed to either be bound or have rebind * work item scheduled. */ -static void rebind_workers(struct global_cwq *gcwq) - __releases(&gcwq->lock) __acquires(&gcwq->lock) +static void gcwq_associate(struct global_cwq *gcwq) { struct idle_rebind idle_rebind; struct worker_pool *pool; @@ -1387,10 +1388,10 @@ static void rebind_workers(struct global_cwq *gcwq) struct hlist_node *pos; int i; - lockdep_assert_held(&gcwq->lock); + gcwq_claim_management(gcwq); + spin_lock_irq(&gcwq->lock); - for_each_worker_pool(pool, gcwq) - lockdep_assert_held(&pool->manager_mutex); + gcwq->flags &= ~GCWQ_DISASSOCIATED; /* * Rebind idle workers. Interlocked both ways. We wait for @@ -1477,8 +1478,11 @@ retry: if (--idle_rebind.cnt) { spin_unlock_irq(&gcwq->lock); wait_for_completion(&idle_rebind.done); - spin_lock_irq(&gcwq->lock); + } else { + spin_unlock_irq(&gcwq->lock); } + + gcwq_release_management(gcwq); } static struct worker *alloc_worker(void) @@ -3496,12 +3500,7 @@ static int __devinit workqueue_cpu_up_callback(struct notifier_block *nfb, case CPU_DOWN_FAILED: case CPU_ONLINE: - gcwq_claim_management(gcwq); - spin_lock_irq(&gcwq->lock); - gcwq->flags &= ~GCWQ_DISASSOCIATED; - rebind_workers(gcwq); - spin_unlock_irq(&gcwq->lock); - gcwq_release_management(gcwq); + gcwq_associate(gcwq); break; } return NOTIFY_OK; -- 1.7.7.3