From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753940AbdJIGdU (ORCPT ); Mon, 9 Oct 2017 02:33:20 -0400 Received: from mx2.suse.de ([195.135.220.15]:37638 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753797AbdJIGdT (ORCPT ); Mon, 9 Oct 2017 02:33:19 -0400 Date: Mon, 9 Oct 2017 08:33:16 +0200 From: Michal Hocko To: Yang Shi Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] mm: oom: show unreclaimable slab info when unreclaimable slabs > user memory Message-ID: <20171009063316.qjmunbabyr2nzh52@dhcp22.suse.cz> References: <1507152550-46205-1-git-send-email-yang.s@alibaba-inc.com> <1507152550-46205-4-git-send-email-yang.s@alibaba-inc.com> <20171006093702.3ca2p6ymyycwfgbk@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat 07-10-17 00:37:55, Yang Shi wrote: > > > On 10/6/17 2:37 AM, Michal Hocko wrote: > > On Thu 05-10-17 05:29:10, Yang Shi wrote: [...] > > > + list_for_each_entry_safe(s, s2, &slab_caches, list) { > > > + if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT)) > > > + continue; > > > + > > > + memset(&sinfo, 0, sizeof(sinfo)); > > > > why do you zero out the structure. All the fields you are printing are > > filled out in get_slabinfo. > > No special reason, just wipe out the potential stale data on the stack. Do not add code that has no meaning. The OOM killer is a slow path but that doesn't mean we should throw spare cycles out of the window. -- Michal Hocko SUSE Labs