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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 DD276C433EF for ; Mon, 20 Sep 2021 11:44:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD46560F56 for ; Mon, 20 Sep 2021 11:44:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237102AbhITLp2 (ORCPT ); Mon, 20 Sep 2021 07:45:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230349AbhITLp1 (ORCPT ); Mon, 20 Sep 2021 07:45:27 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F361C061574; Mon, 20 Sep 2021 04:44:00 -0700 (PDT) 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> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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