Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752441AbbLRLy7 (ORCPT ); Fri, 18 Dec 2015 06:54:59 -0500 Received: from mail-wm0-f51.google.com ([74.125.82.51]:35164 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751794AbbLRLy6 (ORCPT ); Fri, 18 Dec 2015 06:54:58 -0500 Date: Fri, 18 Dec 2015 12:54:55 +0100 From: Michal Hocko To: Andrew Morton Cc: Linus Torvalds , Mel Gorman , Tetsuo Handa , David Rientjes , Oleg Nesterov , Hugh Dickins , Andrea Argangeli , Rik van Riel , linux-mm , LKML Subject: Re: [PATCH 1/2] mm, oom: introduce oom reaper Message-ID: <20151218115454.GE28443@dhcp22.suse.cz> References: <1450204575-13052-1-git-send-email-mhocko@kernel.org> <20151216165035.38a4d9b84600d6348a3cf4bf@linux-foundation.org> <20151217130223.GE18625@dhcp22.suse.cz> <20151217120004.b5f849e1613a3a367482b379@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151217120004.b5f849e1613a3a367482b379@linux-foundation.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1501 Lines: 45 On Thu 17-12-15 12:00:04, Andrew Morton wrote: > On Thu, 17 Dec 2015 11:55:11 -0800 Linus Torvalds wrote: > > > On Thu, Dec 17, 2015 at 5:02 AM, Michal Hocko wrote: > > > Ups. You are right. I will go with msleep_interruptible(100). > > > > I don't think that's right. > > > > If a signal happens, that loop is now (again) just busy-looping. > > It's called only by a kernel thread so no signal_pending(). Yes that was the thinking. > This relationship is a bit unobvious and fragile, but we do it in > quite a few places. I guess Linus is right and __set_task_state(current, TASK_IDLE) would be better and easier to read. --- diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 4b0a5d8b92e1..eed99506b891 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -472,8 +472,10 @@ static void oom_reap_vmas(struct mm_struct *mm) int attempts = 0; /* Retry the down_read_trylock(mmap_sem) a few times */ - while (attempts++ < 10 && !__oom_reap_vmas(mm)) - msleep_interruptible(100); + while (attempts++ < 10 && !__oom_reap_vmas(mm)) { + __set_task_state(current, TASK_IDLE); + schedule_timeout(HZ/10); + } /* Drop a reference taken by wake_oom_reaper */ mmdrop(mm); -- Michal Hocko SUSE Labs -- 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/