From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id 134D76B005D for ; Thu, 15 Feb 2018 07:06:11 -0500 (EST) Received: by mail-wr0-f200.google.com with SMTP id r15so1704495wrc.11 for ; Thu, 15 Feb 2018 04:06:11 -0800 (PST) Received: from outbound-smtp20.blacknight.com (outbound-smtp20.blacknight.com. [46.22.139.247]) by mx.google.com with ESMTPS id e29si555218eda.89.2018.02.15.04.06.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 15 Feb 2018 04:06:09 -0800 (PST) Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp20.blacknight.com (Postfix) with ESMTPS id A6B0F1C5014 for ; Thu, 15 Feb 2018 12:06:08 +0000 (GMT) Date: Thu, 15 Feb 2018 12:06:08 +0000 From: Mel Gorman Subject: Re: [PATCH v2 1/2] free_pcppages_bulk: do not hold lock when picking pages to free Message-ID: <20180215120608.g5wj2qb2thkkzu5e@techsingularity.net> References: <20180124023050.20097-1-aaron.lu@intel.com> <20180124163926.c7ptagn655aeiut3@techsingularity.net> <20180125072144.GA27678@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20180125072144.GA27678@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Aaron Lu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Huang Ying , Dave Hansen , Kemi Wang , Tim Chen , Andi Kleen , Michal Hocko , Vlastimil Babka On Thu, Jan 25, 2018 at 03:21:44PM +0800, Aaron Lu wrote: > When freeing a batch of pages from Per-CPU-Pages(PCP) back to buddy, > the zone->lock is held and then pages are chosen from PCP's migratetype > list. While there is actually no need to do this 'choose part' under > lock since it's PCP pages, the only CPU that can touch them is us and > irq is also disabled. > > Moving this part outside could reduce lock held time and improve > performance. Test with will-it-scale/page_fault1 full load: > > kernel Broadwell(2S) Skylake(2S) Broadwell(4S) Skylake(4S) > v4.15-rc4 9037332 8000124 13642741 15728686 > this patch 9608786 +6.3% 8368915 +4.6% 14042169 +2.9% 17433559 +10.8% > > What the test does is: starts $nr_cpu processes and each will repeatedly > do the following for 5 minutes: > 1 mmap 128M anonymouse space; > 2 write access to that space; > 3 munmap. > The score is the aggregated iteration. > > https://github.com/antonblanchard/will-it-scale/blob/master/tests/page_fault1.c > > Acked-by: Mel Gorman > Signed-off-by: Aaron Lu It looks like this series may have gotten lost because it was embedded within an existing thread or else it was the proximity to the merge window. I suggest a rebase, retest and resubmit unless there was some major objection that I missed. Patch 1 is fine by me at least. I never explicitly acked patch 2 but I've no major objection to it, just am a tad uncomfortable with prefetch magic sauce in general. -- 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