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 X-Spam-Level: X-Spam-Status: No, score=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 89D80C433EF for ; Mon, 20 Sep 2021 11:43:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 060E760F26 for ; Mon, 20 Sep 2021 11:43:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 060E760F26 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 9227B900003; Mon, 20 Sep 2021 07:43:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8D20A900002; Mon, 20 Sep 2021 07:43:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7C081900003; Mon, 20 Sep 2021 07:43:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0165.hostedemail.com [216.40.44.165]) by kanga.kvack.org (Postfix) with ESMTP id 6F55B900002 for ; Mon, 20 Sep 2021 07:43:04 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 2793229DF6 for ; Mon, 20 Sep 2021 11:43:04 +0000 (UTC) X-FDA: 78607765488.23.684C0E5 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf14.hostedemail.com (Postfix) with ESMTP id ABB00600198F for ; Mon, 20 Sep 2021 11:43:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=73CcxbzrLuRLQC2uzjqV9MUFQBB/nbWPYSvLt6dDtD8=; b=E4HwcLrqx1S70L2dkNRWIqtx/r BfRukxgUQXxNxbT4s4RutoZNnEQphu3KCSDk03B9neeEhQoQLGbps0NbSwL1WL1/upXGXYPfurFXn ZWgtDQwdVKWWuByTox7JDbS4nn9nAr5WYNvvsk9Ma6DdnkvZ8Jyi0zaKL9LQtWFd3C6O4umApqM7Z 24WPLVC4v0JjQJogD/aSsYmaka4UX0Vkl3x01zpsBvt5a1uoOYbYpcwf3QCeUMxieb7z1B3Sn8wss 2Q6hGJDcjqa6Yntg3YNBGcqhVtKZVc1twxEbWJgY5QvR95mAAYHxI0V+QkU7wGieh0rKGCjeUwLOb 7n60duwg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mSHh6-002ceI-Gb; Mon, 20 Sep 2021 11:42:49 +0000 Date: Mon, 20 Sep 2021 12:42:44 +0100 From: Matthew Wilcox To: Mel Gorman Cc: Linux-MM , NeilBrown , Theodore Ts'o , Andreas Dilger , "Darrick J . Wong" , Michal Hocko , Dave Chinner , Rik van Riel , Vlastimil Babka , Johannes Weiner , Jonathan Corbet , Linux-fsdevel , LKML Subject: Re: [RFC PATCH 0/5] Remove dependency on congestion_wait in mm/ Message-ID: References: <20210920085436.20939-1-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210920085436.20939-1-mgorman@techsingularity.net> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: ABB00600198F X-Stat-Signature: jqfhr3onm1uuojmxnnzj1z9cimbdxwe6 Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=E4HwcLrq; spf=none (imf14.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-HE-Tag: 1632138183-526217 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 Mon, Sep 20, 2021 at 09:54:31AM +0100, Mel Gorman wrote: > This has been lightly tested only and the testing was useless as the > relevant code was not executed. The workload configurations I had that > used to trigger these corner cases no longer work (yey?) and I'll need > to implement a new synthetic workload. If someone is aware of a realistic > workload that forces reclaim activity to the point where reclaim stalls > then kindly share the details. The stereeotypical "stalling on I/O" problem is to plug in one of the crap USB drives you were given at a trade show and simply dd if=/dev/zero of=/dev/sdb sync You can also set up qemu to have extremely slow I/O performance: https://serverfault.com/questions/675704/extremely-slow-qemu-storage-performance-with-qcow2-images