From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f182.google.com (mail-wi0-f182.google.com [209.85.212.182]) by kanga.kvack.org (Postfix) with ESMTP id E5DAE800CA for ; Fri, 7 Nov 2014 11:54:19 -0500 (EST) Received: by mail-wi0-f182.google.com with SMTP id d1so5144243wiv.3 for ; Fri, 07 Nov 2014 08:54:19 -0800 (PST) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id v6si16122793wjr.171.2014.11.07.08.54.19 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 07 Nov 2014 08:54:19 -0800 (PST) Message-ID: <545CF938.7050906@suse.cz> Date: Fri, 07 Nov 2014 17:54:16 +0100 From: Vlastimil Babka MIME-Version: 1.0 Subject: Re: 3.18-rc3: soft lockup in compact_zone, dead machine References: <20141107100611.GA4175@amd> In-Reply-To: <20141107100611.GA4175@amd> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Pavel Machek , kernel list Cc: Andrew Morton , David Rientjes , linux-mm , Joonsoo Kim On 11/07/2014 11:06 AM, Pavel Machek wrote: > Hi! > > My main machine died completely, it seems that original failure was > soft lockup in compact_zone(). (expanding CC) Welcome to the club... http://article.gmane.org/gmane.linux.kernel.mm/124451/match=isolate_freepages_block+very+high+intermittent+overhead https://lkml.org/lkml/2014/11/4/144 https://lkml.org/lkml/2014/11/4/904 How reproducible is your case? So far it seems that git revert e14c720efdd73c6d69cd8d07fa894bcd11fe1973 helped one of the reporters. I still don't know what's wrong, but suspect a free scanner (cc->free_pfn) position being broken (i.e. underflow), which would allow isolate_migratepages() to run for a loooooooong time. The code does cond_resched() periodically, so soft lockup looks strange, but I guess that can happen in some contexts? Vlastimil -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org