Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932487Ab1EJIPK (ORCPT ); Tue, 10 May 2011 04:15:10 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:48763 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753128Ab1EJIPG (ORCPT ); Tue, 10 May 2011 04:15:06 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: KOSAKI Motohiro Subject: [PATCH 2/4] oom: kill younger process first Cc: kosaki.motohiro@jp.fujitsu.com, CAI Qian , avagin@gmail.com, Andrey Vagin , Andrew Morton , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Minchan Kim , David Rientjes , Hugh Dickins , Oleg Nesterov In-Reply-To: <20110510171335.16A7.A69D9226@jp.fujitsu.com> References: <20110509182110.167F.A69D9226@jp.fujitsu.com> <20110510171335.16A7.A69D9226@jp.fujitsu.com> Message-Id: <20110510171641.16AF.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Mailer: Becky! ver. 2.56.05 [ja] Date: Tue, 10 May 2011 17:15:01 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2082 Lines: 62 This patch introduces do_each_thread_reverse() and select_bad_process() uses it. The benefits are two, 1) oom-killer can kill younger process than older if they have a same oom score. Usually younger process is less important. 2) younger task often have PF_EXITING because shell script makes a lot of short lived processes. Reverse order search can detect it faster. Reported-by: CAI Qian Signed-off-by: KOSAKI Motohiro --- include/linux/sched.h | 6 ++++++ mm/oom_kill.c | 2 +- 2 files changed, 7 insertions(+), 1 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 013314a..a0a8339 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2194,6 +2194,9 @@ static inline unsigned long wait_task_inactive(struct task_struct *p, #define next_task(p) \ list_entry_rcu((p)->tasks.next, struct task_struct, tasks) +#define prev_task(p) \ + list_entry_rcu((p)->tasks.prev, struct task_struct, tasks) + #define for_each_process(p) \ for (p = &init_task ; (p = next_task(p)) != &init_task ; ) @@ -2206,6 +2209,9 @@ extern bool current_is_single_threaded(void); #define do_each_thread(g, t) \ for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do +#define do_each_thread_reverse(g, t) \ + for (g = t = &init_task ; (g = t = prev_task(g)) != &init_task ; ) do + #define while_each_thread(g, t) \ while ((t = next_thread(t)) != g) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 118d958..0cf5091 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -282,7 +282,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, struct task_struct *chosen = NULL; *ppoints = 0; - do_each_thread(g, p) { + do_each_thread_reverse(g, p) { unsigned int points; if (!p->mm) -- 1.7.3.1 -- 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/