From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756305AbaEGQhV (ORCPT ); Wed, 7 May 2014 12:37:21 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:48156 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756039AbaEGQhQ (ORCPT ); Wed, 7 May 2014 12:37:16 -0400 From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Christoph Lameter , Kevin Hilman , Lai Jiangshan , Mike Galbraith , "Paul E. McKenney" , Tejun Heo , Viresh Kumar Subject: [PATCH 5/6] workqueue: Allow modifying low level unbound workqueue cpumask Date: Wed, 7 May 2014 18:37:00 +0200 Message-Id: <1399480621-19555-6-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1399480621-19555-1-git-send-email-fweisbec@gmail.com> References: <1399480621-19555-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow to modify the low-level unbound workqueues cpumask through sysfs. This is performed by traversing the entire workqueue list and calling apply_workqueue_attrs() on the unbound workqueues. Cc: Christoph Lameter Cc: Kevin Hilman Cc: Lai Jiangshan Cc: Mike Galbraith Cc: Paul E. McKenney Cc: Tejun Heo Cc: Viresh Kumar Signed-off-by: Frederic Weisbecker --- kernel/workqueue.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 63 insertions(+), 2 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 2aa296d..5978cee 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -293,7 +293,7 @@ static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ static LIST_HEAD(workqueues); /* PL: list of all workqueues */ static bool workqueue_freezing; /* PL: have wqs started freezing? */ -static cpumask_var_t wq_unbound_cpumask; +static cpumask_var_t wq_unbound_cpumask; /* PL: low level cpumask for all unbound wqs */ /* the per-cpu worker pools */ static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], @@ -4084,19 +4084,80 @@ static struct bus_type wq_subsys = { .dev_groups = wq_sysfs_groups, }; +static int unbounds_cpumask_apply(cpumask_var_t cpumask) +{ + struct workqueue_struct *wq; + int ret; + + lockdep_assert_held(&wq_pool_mutex); + + list_for_each_entry(wq, &workqueues, list) { + struct workqueue_attrs *attrs; + + if (!(wq->flags & WQ_UNBOUND)) + continue; + + attrs = wq_sysfs_prep_attrs(wq); + if (!attrs) + return -ENOMEM; + + ret = apply_workqueue_attrs_locked(wq, attrs, cpumask); + free_workqueue_attrs(attrs); + if (ret) + break; + } + + return 0; +} + +static ssize_t unbounds_cpumask_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + cpumask_var_t cpumask; + int ret = -EINVAL; + + if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL)) + return -ENOMEM; + + ret = cpumask_parse(buf, cpumask); + if (ret) + goto out; + + get_online_cpus(); + if (cpumask_intersects(cpumask, cpu_online_mask)) { + mutex_lock(&wq_pool_mutex); + ret = unbounds_cpumask_apply(cpumask); + if (ret < 0) { + /* Warn if rollback itself fails */ + WARN_ON_ONCE(unbounds_cpumask_apply(wq_unbound_cpumask)); + } else { + cpumask_copy(wq_unbound_cpumask, cpumask); + } + mutex_unlock(&wq_pool_mutex); + } + put_online_cpus(); +out: + free_cpumask_var(cpumask); + return ret ? ret : count; +} + static ssize_t unbounds_cpumask_show(struct device *dev, struct device_attribute *attr, char *buf) { int written; + mutex_lock(&wq_pool_mutex); written = cpumask_scnprintf(buf, PAGE_SIZE, wq_unbound_cpumask); + mutex_unlock(&wq_pool_mutex); + written += scnprintf(buf + written, PAGE_SIZE - written, "\n"); return written; } static struct device_attribute wq_sysfs_cpumask_attr = - __ATTR(cpumask, 0444, unbounds_cpumask_show, NULL); + __ATTR(cpumask, 0644, unbounds_cpumask_show, unbounds_cpumask_store); static int __init wq_sysfs_init(void) { -- 1.8.3.1