From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9CB8C433F5 for ; Fri, 22 Oct 2021 08:14:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA12861056 for ; Fri, 22 Oct 2021 08:14:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232249AbhJVIRL (ORCPT ); Fri, 22 Oct 2021 04:17:11 -0400 Received: from outbound-smtp47.blacknight.com ([46.22.136.64]:34099 "EHLO outbound-smtp47.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232021AbhJVIRK (ORCPT ); Fri, 22 Oct 2021 04:17:10 -0400 Received: from mail.blacknight.com (pemlinmail06.blacknight.ie [81.17.255.152]) by outbound-smtp47.blacknight.com (Postfix) with ESMTPS id E543EFB318 for ; Fri, 22 Oct 2021 09:14:51 +0100 (IST) Received: (qmail 24056 invoked from network); 22 Oct 2021 08:14:51 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.17.29]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 22 Oct 2021 08:14:51 -0000 Date: Fri, 22 Oct 2021 09:14:50 +0100 From: Mel Gorman To: NeilBrown Cc: Andrew Morton , Theodore Ts'o , Andreas Dilger , "Darrick J . Wong" , Matthew Wilcox , Michal Hocko , Dave Chinner , Rik van Riel , Vlastimil Babka , Johannes Weiner , Jonathan Corbet , Linux-MM , Linux-fsdevel , LKML Subject: Re: [PATCH 7/8] mm/vmscan: Increase the timeout if page reclaim is not making progress Message-ID: <20211022081450.GH3959@techsingularity.net> References: <20211019090108.25501-1-mgorman@techsingularity.net> <20211019090108.25501-8-mgorman@techsingularity.net> <163486486314.17149.7181265861483962024@noble.neil.brown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <163486486314.17149.7181265861483962024@noble.neil.brown.name> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 22, 2021 at 12:07:43PM +1100, NeilBrown wrote: > On Tue, 19 Oct 2021, Mel Gorman wrote: > > Tracing of the stutterp workload showed the following delays > > > > 1 usect_delayed=124000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 1 usect_delayed=128000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 1 usect_delayed=176000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 1 usect_delayed=536000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 1 usect_delayed=544000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 1 usect_delayed=556000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 1 usect_delayed=624000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 1 usect_delayed=716000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 1 usect_delayed=772000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 2 usect_delayed=512000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 16 usect_delayed=120000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 53 usect_delayed=116000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 116 usect_delayed=112000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 5907 usect_delayed=108000 reason=VMSCAN_THROTTLE_NOPROGRESS > > 71741 usect_delayed=104000 reason=VMSCAN_THROTTLE_NOPROGRESS > > > > All the throttling hit the full timeout and then there was wakeup delays > > meaning that the wakeups are premature as no other reclaimer such as > > kswapd has made progress. This patch increases the maximum timeout. > > Would love to see the comparable tracing results for after the patch. > They're in the leader. The trace figures in the changelog are the ones I had at the time the patch was developed and I didn't keep them up to date to reduce overall test time. At the last set of results, some throttling was still hitting the full timeout; [....] 843 usec_timeout=500000 usect_delayed=12000 reason=VMSCAN_THROTTLE_NOPROGRESS 1299 usec_timeout=500000 usect_delayed=104000 reason=VMSCAN_THROTTLE_NOPROGRESS 2839 usec_timeout=500000 usect_delayed=8000 reason=VMSCAN_THROTTLE_NOPROGRESS 10111 usec_timeout=500000 usect_delayed=4000 reason=VMSCAN_THROTTLE_NOPROGRESS 21492 usec_timeout=500000 usect_delayed=0 reason=VMSCAN_THROTTLE_NOPROGRESS 36441 usec_timeout=500000 usect_delayed=500000 reason=VMSCAN_THROTTLE_NOPROGRESS -- Mel Gorman SUSE Labs