Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933053Ab3DDCGG (ORCPT ); Wed, 3 Apr 2013 22:06:06 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:53380 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S932907Ab3DDCF7 (ORCPT ); Wed, 3 Apr 2013 22:05:59 -0400 X-IronPort-AV: E=Sophos;i="4.87,404,1363104000"; d="scan'208";a="6998071" From: Lai Jiangshan To: Tejun Heo , linux-kernel@vger.kernel.org Cc: Lai Jiangshan Subject: [PATCH 4/7] workqueue: simplify workqueue_cpu_up_callback(CPU_ONLINE) Date: Thu, 4 Apr 2013 10:05:35 +0800 Message-Id: <1365041143-3088-4-git-send-email-laijs@cn.fujitsu.com> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <1365041143-3088-1-git-send-email-laijs@cn.fujitsu.com> References: <1365041143-3088-1-git-send-email-laijs@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/04/04 10:04:57, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/04/04 10:04:57, Serialize complete at 2013/04/04 10:04:57 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4439 Lines: 143 If we have 4096 CPUs, workqueue_cpu_up_callback() will travel too much CPUs, to avoid it, we use for_each_cpu_worker_pool() for the cpu pools and use for_each_unbound_pool() for unbound pools. After it, for_each_pool() becomes unused, but we keep it for future possible usage. Signed-off-by: Lai Jiangshan --- kernel/workqueue.c | 53 ++++++++++++++++++++++++++++++++++----------------- 1 files changed, 35 insertions(+), 18 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b4369de..a383eaf 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -354,6 +354,23 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to, else /** + * for_each_unbound_pool - iterate through all unbound worker_pools in the system + * @pool: iteration cursor + * @bkt: bucket (of integer) used for iteration + * + * This must be called either with wq_pool_mutex held or sched RCU read + * locked. If the pool needs to be used beyond the locking in effect, the + * caller is responsible for guaranteeing that the pool stays online. + * + * The if/else clause exists only for the lockdep assertion and can be + * ignored. + */ +#define for_each_unbound_pool(pool, bkt) \ + hash_for_each(unbound_pool_hash, bkt, pool, hash_node) \ + if (({ assert_rcu_or_pool_mutex(); false; })) { } \ + else + +/** * for_each_pool_worker - iterate through all workers of a worker_pool * @worker: iteration cursor * @wi: integer used for iteration @@ -4442,7 +4459,7 @@ static void associate_cpu_pool(struct worker_pool *pool) struct worker *worker; int wi; - lockdep_assert_held(&pool->manager_mutex); + mutex_lock(&pool->manager_mutex); /* * Restore CPU affinity of all workers. As all idle workers should @@ -4454,7 +4471,7 @@ static void associate_cpu_pool(struct worker_pool *pool) for_each_pool_worker(worker, wi, pool) if (WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask) < 0)) - return; + goto out_unlock; spin_lock_irq(&pool->lock); @@ -4495,6 +4512,9 @@ static void associate_cpu_pool(struct worker_pool *pool) pool->flags &= ~POOL_DISASSOCIATED; spin_unlock_irq(&pool->lock); + +out_unlock: + mutex_unlock(&pool->manager_mutex); } /** @@ -4509,25 +4529,28 @@ static void associate_cpu_pool(struct worker_pool *pool) */ static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu) { - static cpumask_t cpumask; + static cpumask_t cpumask; /* protected by wq_pool_mutex */ struct worker *worker; int wi; - lockdep_assert_held(&pool->manager_mutex); + mutex_lock(&pool->manager_mutex); /* is @cpu allowed for @pool? */ if (!cpumask_test_cpu(cpu, pool->attrs->cpumask)) - return; + goto out_unlock; /* is @cpu the only online CPU? */ cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask); if (cpumask_weight(&cpumask) != 1) - return; + goto out_unlock; /* as we're called from CPU_ONLINE, the following shouldn't fail */ for_each_pool_worker(worker, wi, pool) WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask) < 0); + +out_unlock: + mutex_unlock(&pool->manager_mutex); } /* @@ -4541,7 +4564,7 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, int cpu = (unsigned long)hcpu; struct worker_pool *pool; struct workqueue_struct *wq; - int pi; + int bkt; switch (action & ~CPU_TASKS_FROZEN) { case CPU_UP_PREPARE: @@ -4555,19 +4578,13 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, case CPU_DOWN_FAILED: case CPU_ONLINE: - mutex_lock(&wq_pool_mutex); + for_each_cpu_worker_pool(pool, cpu) + associate_cpu_pool(pool); - for_each_pool(pool, pi) { - mutex_lock(&pool->manager_mutex); - - if (pool->cpu == cpu) { - associate_cpu_pool(pool); - } else if (pool->cpu < 0) { - restore_unbound_workers_cpumask(pool, cpu); - } + mutex_lock(&wq_pool_mutex); - mutex_unlock(&pool->manager_mutex); - } + for_each_unbound_pool(pool, bkt) + restore_unbound_workers_cpumask(pool, cpu); /* update NUMA affinity of unbound workqueues */ list_for_each_entry(wq, &workqueues, list) -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/