From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753570AbdKOOnb (ORCPT ); Wed, 15 Nov 2017 09:43:31 -0500 Received: from outbound-smtp19.blacknight.com ([46.22.139.246]:52453 "EHLO outbound-smtp19.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758062AbdKOOnR (ORCPT ); Wed, 15 Nov 2017 09:43:17 -0500 Date: Wed, 15 Nov 2017 14:43:14 +0000 From: Mel Gorman To: Michal Hocko Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, yasu.isimatu@gmail.com, koki.sanagi@us.fujitsu.com Subject: Re: [PATCH] mm, meminit: Serially initialise deferred memory if trace_buf_size is specified Message-ID: <20171115144314.xwdi2sbcn6m6lqdo@techsingularity.net> References: <20171115085556.fla7upm3nkydlflp@techsingularity.net> <20171115115559.rjb5hy6d6332jgjj@dhcp22.suse.cz> <20171115141329.ieoqvyoavmv6gnea@techsingularity.net> <20171115142816.zxdgkad3ch2bih6d@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20171115142816.zxdgkad3ch2bih6d@dhcp22.suse.cz> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 15, 2017 at 03:28:16PM +0100, Michal Hocko wrote: > On Wed 15-11-17 14:13:29, Mel Gorman wrote: > [...] > > I doubt anyone well. Even the original reporter appeared to pick that > > particular value just to trigger the OOM. > > Then why do we care at all? The trace buffer size can be configured from > the userspace if it is not sufficiently large IIRC. > I guess there is the potential that the trace buffer needs to be large enough early on in boot but I'm not sure why it would need to be that large to be honest. Bottom line, it's fairly trivial to just serialise meminit in the event that it's resized from command line. I'm also ok with just leaving this is as a "don't set the buffer that large" but I don't think spreading meminit concerns into ftrace is a good idea. -- Mel Gorman SUSE Labs