Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934534Ab1ETICa (ORCPT ); Fri, 20 May 2011 04:02:30 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:49028 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934364Ab1ETIC0 (ORCPT ); Fri, 20 May 2011 04:02:26 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Message-ID: <4DD62007.6020600@jp.fujitsu.com> Date: Fri, 20 May 2011 17:02:15 +0900 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; ja; rv:1.9.2.17) Gecko/20110414 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: kosaki.motohiro@jp.fujitsu.com CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, caiqian@redhat.com, rientjes@google.com, hughd@google.com, kamezawa.hiroyu@jp.fujitsu.com, minchan.kim@gmail.com, oleg@redhat.com Subject: [PATCH 2/5] oom: kill younger process first References: <4DD61F80.1020505@jp.fujitsu.com> In-Reply-To: <4DD61F80.1020505@jp.fujitsu.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2412 Lines: 69 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 Cc: Minchan Kim Cc: David Rientjes Cc: KAMEZAWA Hiroyuki --- include/linux/sched.h | 11 +++++++++++ mm/oom_kill.c | 2 +- 2 files changed, 12 insertions(+), 1 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 013314a..3698379 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((p)->tasks.prev, struct task_struct, tasks) + #define for_each_process(p) \ for (p = &init_task ; (p = next_task(p)) != &init_task ; ) @@ -2206,6 +2209,14 @@ 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 +/* + * Similar to do_each_thread(). but two difference are there. + * - traverse tasks reverse order (i.e. younger to older) + * - caller must hold tasklist_lock. rcu_read_lock isn't enough +*/ +#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 43d32ae..e6a6c6f 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/