From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752739AbaIXO5Z (ORCPT ); Wed, 24 Sep 2014 10:57:25 -0400 Received: from terminus.zytor.com ([198.137.202.10]:59637 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751239AbaIXO45 (ORCPT ); Wed, 24 Sep 2014 10:56:57 -0400 Date: Wed, 24 Sep 2014 07:56:06 -0700 From: tip-bot for Oleg Nesterov Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, umgwanakikbuti@gmail.com, tkhai@yandex.ru, tglx@linutronix.de, oleg@redhat.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, umgwanakikbuti@gmail.com, tkhai@yandex.ru, oleg@redhat.com, tglx@linutronix.de In-Reply-To: <20140921193338.GA28621@redhat.com> References: <20140921193338.GA28621@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched: normalize_rt_tasks(): Don' t use _irqsave for tasklist_lock, use task_rq_lock() Git-Commit-ID: 3472eaa1f12e217e2b8b0ef658ff861b2308cbbd X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 3472eaa1f12e217e2b8b0ef658ff861b2308cbbd Gitweb: http://git.kernel.org/tip/3472eaa1f12e217e2b8b0ef658ff861b2308cbbd Author: Oleg Nesterov AuthorDate: Sun, 21 Sep 2014 21:33:38 +0200 Committer: Ingo Molnar CommitDate: Wed, 24 Sep 2014 14:47:03 +0200 sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock() 1. read_lock(tasklist_lock) does not need to disable irqs. 2. ->mm != NULL is a common mistake, use PF_KTHREAD. 3. The second ->mm check can be simply removed. 4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) + __task_rq_lock(). Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Cc: Kirill Tkhai Cc: Mike Galbraith Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20140921193338.GA28621@redhat.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0abfb7e..d65566d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7220,12 +7220,12 @@ void normalize_rt_tasks(void) unsigned long flags; struct rq *rq; - read_lock_irqsave(&tasklist_lock, flags); + read_lock(&tasklist_lock); for_each_process_thread(g, p) { /* * Only normalize user tasks: */ - if (!p->mm) + if (p->flags & PF_KTHREAD) continue; p->se.exec_start = 0; @@ -7240,20 +7240,16 @@ void normalize_rt_tasks(void) * Renice negative nice level userspace * tasks back to 0: */ - if (task_nice(p) < 0 && p->mm) + if (task_nice(p) < 0) set_user_nice(p, 0); continue; } - raw_spin_lock(&p->pi_lock); - rq = __task_rq_lock(p); - + rq = task_rq_lock(p, &flags); normalize_task(rq, p); - - __task_rq_unlock(rq); - raw_spin_unlock(&p->pi_lock); + task_rq_unlock(rq, p, &flags); } - read_unlock_irqrestore(&tasklist_lock, flags); + read_unlock(&tasklist_lock); } #endif /* CONFIG_MAGIC_SYSRQ */