From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f181.google.com (mail-wi0-f181.google.com [209.85.212.181]) by kanga.kvack.org (Postfix) with ESMTP id 891936B0258 for ; Tue, 8 Sep 2015 12:29:06 -0400 (EDT) Received: by wiclk2 with SMTP id lk2so126970191wic.0 for ; Tue, 08 Sep 2015 09:29:06 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id hd3si6793846wib.114.2015.09.08.09.29.05 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 08 Sep 2015 09:29:05 -0700 (PDT) Subject: Re: [PATCH 3/3] mm, compaction: disginguish contended status in tracepoint References: <1440689044-2922-1-git-send-email-vbabka@suse.cz> <1440689044-2922-3-git-send-email-vbabka@suse.cz> <20150907055306.GD21207@js1304-P5Q-DELUXE> From: Vlastimil Babka Message-ID: <55EF0CCD.7000009@suse.cz> Date: Tue, 8 Sep 2015 18:29:01 +0200 MIME-Version: 1.0 In-Reply-To: <20150907055306.GD21207@js1304-P5Q-DELUXE> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Joonsoo Kim Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman , David Rientjes On 09/07/2015 07:53 AM, Joonsoo Kim wrote: > On Thu, Aug 27, 2015 at 05:24:04PM +0200, Vlastimil Babka wrote: >> Compaction returns prematurely with COMPACT_PARTIAL when contended or has fatal >> signal pending. This is ok for the callers, but might be misleading in the >> traces, as the usual reason to return COMPACT_PARTIAL is that we think the >> allocation should succeed. This patch distinguishes the premature ending >> condition. Further distinguishing the exact reason seems unnecessary for now. > > isolate_migratepages() could return ISOLATE_ABORT and skip to call > compact_finished(). trace_mm_compaction_end() will print > COMPACT_PARTIAL in this case and we cannot distinguish premature > ending condition. Is it okay? Thanks, that could be indeed misleading. It will affect trace_mm_compaction_end() which also prints COMPACT_PARTIAL for COMPACT_CONTENDED case as it's already changed in compact_finished(). And there's no compaction_finished trace event to clarify. Some cases for abort can be inferred from trace_mm_compaction_isolate_migratepages, but not all. Maybe I could move the post-filtering for COMPACT_CONTENDED, now done in compact_finished() to the end of compact_zone()? That would both enhance also trace_mm_compaction_end() and allow setting proper "ret" value for the ISOLATE_ABORT case. The abort only happens for sched contention or too_many_isolated(), which is basically another form of contention... > Thanks. > -- 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