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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3AC0DC433EF for ; Tue, 30 Nov 2021 13:09:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237817AbhK3NM7 (ORCPT ); Tue, 30 Nov 2021 08:12:59 -0500 Received: from outbound-smtp47.blacknight.com ([46.22.136.64]:41653 "EHLO outbound-smtp47.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236313AbhK3NM6 (ORCPT ); Tue, 30 Nov 2021 08:12:58 -0500 Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp47.blacknight.com (Postfix) with ESMTPS id 57AE8FA7E4 for ; Tue, 30 Nov 2021 13:09:38 +0000 (GMT) Received: (qmail 27593 invoked from network); 30 Nov 2021 13:09:38 -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); 30 Nov 2021 13:09:38 -0000 Date: Tue, 30 Nov 2021 13:09:35 +0000 From: Mel Gorman To: Mike Galbraith Cc: Alexey Avramov , Andrew Morton , Michal Hocko , Vlastimil Babka , Rik van Riel , Darrick Wong , regressions@lists.linux.dev, Linux-fsdevel , Linux-MM , LKML Subject: Re: [PATCH 1/1] mm: vmscan: Reduce throttling due to a failure to make progress Message-ID: <20211130130935.GR3366@techsingularity.net> References: <20211125151853.8540-1-mgorman@techsingularity.net> <20211127011246.7a8ac7b8@mail.inbox.lv> <20211129150117.GO3366@techsingularity.net> <20211130112244.GQ3366@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 30, 2021 at 01:51:10PM +0100, Mike Galbraith wrote: > On Tue, 2021-11-30 at 13:00 +0100, Mike Galbraith wrote: > > On Tue, 2021-11-30 at 11:22 +0000, Mel Gorman wrote: > > > On Tue, Nov 30, 2021 at 11:14:32AM +0100, Mike Galbraith wrote: > > > > > ??????} > > > > > +???????if (2 * write_pending <= reclaimable) > > > > > > > > That is always true here... > > > > > > > > > > Always true for you or always true in general? > > > > "Here" as in the boxen located at my GPS coordinates :) > > > > > The intent of the check is "are a majority of reclaimable pages > > > marked WRITE_PENDING?". It's similar to the check that existed prior > > > to 132b0d21d21f ("mm/page_alloc: remove the throttling logic from the > > > page allocator"). > > > > I'll put my trace_printk() back and see if I can't bend-adjust it. > > As it sits, write_pending is always 0 with tail /dev/zero. > That is not a surprise for the test in question as it doesn't trigger a case where there are lots of page cache being marked dirty and write pending. -- Mel Gorman SUSE Labs