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 4519DC433FE for ; Fri, 22 Oct 2021 08:14:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E6CE761056 for ; Fri, 22 Oct 2021 08:14:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E6CE761056 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techsingularity.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 722E4900003; Fri, 22 Oct 2021 04:14:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6AC2A900002; Fri, 22 Oct 2021 04:14:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 57359900003; Fri, 22 Oct 2021 04:14:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0008.hostedemail.com [216.40.44.8]) by kanga.kvack.org (Postfix) with ESMTP id 43301900002 for ; Fri, 22 Oct 2021 04:14:54 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 0201C2C580 for ; Fri, 22 Oct 2021 08:14:54 +0000 (UTC) X-FDA: 78723362508.19.B276608 Received: from outbound-smtp01.blacknight.com (outbound-smtp01.blacknight.com [81.17.249.7]) by imf29.hostedemail.com (Postfix) with ESMTP id 260CF9000249 for ; Fri, 22 Oct 2021 08:14:50 +0000 (UTC) Received: from mail.blacknight.com (pemlinmail06.blacknight.ie [81.17.255.152]) by outbound-smtp01.blacknight.com (Postfix) with ESMTPS id E1F7B500BF 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) X-Rspamd-Queue-Id: 260CF9000249 Authentication-Results: imf29.hostedemail.com; dkim=none; spf=pass (imf29.hostedemail.com: domain of mgorman@techsingularity.net designates 81.17.249.7 as permitted sender) smtp.mailfrom=mgorman@techsingularity.net; dmarc=none X-Stat-Signature: qn93b7sxufujumtwpgjkqpudbeiq5xot X-Rspamd-Server: rspam06 X-HE-Tag: 1634890490-304115 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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