From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755247AbbAFL1r (ORCPT ); Tue, 6 Jan 2015 06:27:47 -0500 Received: from cantor2.suse.de ([195.135.220.15]:38197 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753292AbbAFL1q (ORCPT ); Tue, 6 Jan 2015 06:27:46 -0500 Message-ID: <54ABC6AF.1020108@suse.cz> Date: Tue, 06 Jan 2015 12:27:43 +0100 From: Vlastimil Babka User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Joonsoo Kim , Andrew Morton CC: Mel Gorman , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] mm/compaction: add tracepoint to observe behaviour of compaction defer References: <1417593127-6819-1-git-send-email-iamjoonsoo.kim@lge.com> <1417593127-6819-3-git-send-email-iamjoonsoo.kim@lge.com> In-Reply-To: <1417593127-6819-3-git-send-email-iamjoonsoo.kim@lge.com> Content-Type: text/plain; charset=iso-8859-2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/03/2014 08:52 AM, Joonsoo Kim wrote: > compaction deferring logic is heavy hammer that block the way to > the compaction. It doesn't consider overall system state, so it > could prevent user from doing compaction falsely. In other words, > even if system has enough range of memory to compact, compaction would be > skipped due to compaction deferring logic. This patch add new tracepoint > to understand work of deferring logic. This will also help to check > compaction success and fail. > > Signed-off-by: Joonsoo Kim You only call the tracepoints from try_to_compact_pages(), but the corresponding functions are also called from elsewhere, e.g. kswapd. Shouldn't all be included? Otherwise one might consider the trace as showing a bug, where the defer state suddenly changed without being captured in the trace.