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[195.135.220.15]) by mx.google.com with ESMTPS id e17si192406pgd.109.2019.02.13.08.18.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 13 Feb 2019 08:18:36 -0800 (PST) Received-SPF: softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 85ED4AD74; Wed, 13 Feb 2019 16:18:34 +0000 (UTC) Date: Wed, 13 Feb 2019 17:18:32 +0100 From: Michal Hocko To: Dave Hansen Cc: linux-mm@kvack.org, Pingfan Liu , Peter Zijlstra , x86@kernel.org, Benjamin Herrenschmidt , Michael Ellerman , Tony Luck , linuxppc-dev@lists.ozlabs.org, linux-ia64@vger.kernel.org, LKML , Ingo Molnar Subject: Re: [PATCH v3 2/2] mm: be more verbose about zonelist initialization Message-ID: <20190213161832.GT4525@dhcp22.suse.cz> References: <20190212095343.23315-3-mhocko@kernel.org> <20190213094315.3504-1-mhocko@kernel.org> <1433a7e9-87b2-7e8d-a87d-dcffe486635c@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1433a7e9-87b2-7e8d-a87d-dcffe486635c@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed 13-02-19 08:14:50, Dave Hansen wrote: > On 2/13/19 1:43 AM, Michal Hocko wrote: > > > > We have seen several bugs where zonelists have not been initialized > > properly and it is not really straightforward to track those bugs down. > > One way to help a bit at least is to dump zonelists of each node when > > they are (re)initialized. > > Were you thinking of boot-time bugs and crashes, or just stuff going > wonky after boot? Mostly boot time. I haven't seen hotplug related bugs in this direction. All the issues I have seen so far is that we forget a node altogether and it ends up with no zonelists at all. But who knows maybe we have some hidden bugs where zonelists is initialized only partially for some reason and there is no real way to find out. > We don't have the zonelists dumped in /proc anywhere, do we? Would that > help? I would prefer to not export such an implementation detail into proc -- Michal Hocko SUSE Labs