From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 175C06B0033 for ; Thu, 2 Nov 2017 09:09:45 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id o44so3014646wrf.0 for ; Thu, 02 Nov 2017 06:09:45 -0700 (PDT) Received: from outbound-smtp02.blacknight.com (outbound-smtp02.blacknight.com. [81.17.249.8]) by mx.google.com with ESMTPS id a27si2185651edb.366.2017.11.02.06.09.43 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 02 Nov 2017 06:09:44 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp02.blacknight.com (Postfix) with ESMTPS id 86905987F1 for ; Thu, 2 Nov 2017 13:09:43 +0000 (UTC) Date: Thu, 2 Nov 2017 13:09:43 +0000 From: Mel Gorman Subject: Re: [PATCH 2/3] mm, compaction: split off flag for not updating skip hints Message-ID: <20171102130943.7dpbuecrywtloein@techsingularity.net> References: <20171102121706.21504-1-vbabka@suse.cz> <20171102121706.21504-2-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20171102121706.21504-2-vbabka@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Rientjes , Joonsoo Kim On Thu, Nov 02, 2017 at 01:17:05PM +0100, Vlastimil Babka wrote: > Pageblock skip hints were added as a heuristic for compaction, which shares > core code with CMA. Since CMA reliability would suffer from the heuristics, > compact_control flag ignore_skip_hint was added for the CMA use case. > Since commit 6815bf3f233e ("mm/compaction: respect ignore_skip_hint in > update_pageblock_skip") the flag also means that CMA won't *update* the skip > hints in addition to ignoring them. > > Today, direct compaction can also ignore the skip hints in the last resort > attempt, but there's no reason not to set them when isolation fails in such > case. Thus, this patch splits off a new no_set_skip_hint flag to avoid the > updating, which only CMA sets. This should improve the heuristics a bit, and > allow us to simplify the persistent skip bit handling as the next step. > > Signed-off-by: Vlastimil Babka Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- 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