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=-0.8 required=3.0 tests=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 97633C5ACC4 for ; Wed, 19 Feb 2020 22:42:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 61EEC20656 for ; Wed, 19 Feb 2020 22:42:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 61EEC20656 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kerneltoast.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EAF186B000A; Wed, 19 Feb 2020 17:42:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E5FE66B000C; Wed, 19 Feb 2020 17:42:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D4DA36B000D; Wed, 19 Feb 2020 17:42:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0143.hostedemail.com [216.40.44.143]) by kanga.kvack.org (Postfix) with ESMTP id BD8F96B000A for ; Wed, 19 Feb 2020 17:42:35 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 8368945AA for ; Wed, 19 Feb 2020 22:42:35 +0000 (UTC) X-FDA: 76508352270.22.rifle11_1693b29a9aa40 X-HE-Tag: rifle11_1693b29a9aa40 X-Filterd-Recvd-Size: 3453 Received: from mail-pg1-f193.google.com (mail-pg1-f193.google.com [209.85.215.193]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Wed, 19 Feb 2020 22:42:35 +0000 (UTC) Received: by mail-pg1-f193.google.com with SMTP id z7so843940pgk.7 for ; Wed, 19 Feb 2020 14:42:34 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=OIoZhKbx27/FCo9yilFuIVLxJ+Eh0wcGMXuT/euPHOc=; b=i59AeIkMWLh9spzT3dGdydodMQKIzms5yTwg8cmyu+f+8OgL7GHcvVKQ5woTjIa47+ N4/WfH6eTI/IDPK0v6T8W00dcuJxBM3/fI8XW3xOGmqH4Dx+MmhNudAN6qekSQcXQmDr Vg3HgXkgSPI8fCO1OiBmKQ3TmtA4zAUwWlIr+OfotdG/MQr3yBkgEuPD65GXspMCZmRd NAPpsIzPI3zpzS54DxJHVwi4A8K9Bxf9yrrKwXng6PAeQOLzD5bon/8A2RYsutXcTF7z x6xyoe8U7r5SfLYSKlzPfIyCzhp0Pe8a9lp4U7N60eXbIcSbD5OZqTS2cigoUsb2mwiS xfmA== X-Gm-Message-State: APjAAAWI/ZYtTOFHnffkZH1GppN1e4QLbsdOTXD+C8O3HeUCY3RTvnkp RPqdGv4sZsv0wQXk8BcnmrA= X-Google-Smtp-Source: APXvYqzFd+7FAez8BO6WoN8/0I+p7oskMsNBKXcYctB7DEouDjN17mDU3zO6Ke3OQtZ/LDuGM9pMgQ== X-Received: by 2002:a65:468d:: with SMTP id h13mr3403908pgr.359.1582152154012; Wed, 19 Feb 2020 14:42:34 -0800 (PST) Received: from sultan-book.localdomain ([104.200.129.62]) by smtp.gmail.com with ESMTPSA id d2sm794824pjv.18.2020.02.19.14.42.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Feb 2020 14:42:33 -0800 (PST) Date: Wed, 19 Feb 2020 14:42:31 -0800 From: Sultan Alsawaf To: Mel Gorman Cc: Michal Hocko , Dave Hansen , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner Subject: Re: [PATCH] mm: Stop kswapd early when nothing's waiting for it to free pages Message-ID: <20200219224231.GA5190@sultan-book.localdomain> References: <20200219182522.1960-1-sultan@kerneltoast.com> <20200219194006.GA3075@sultan-book.localdomain> <20200219200527.GF11847@dhcp22.suse.cz> <20200219204220.GA3488@sultan-book.localdomain> <20200219214513.GL3420@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200219214513.GL3420@suse.de> 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 Wed, Feb 19, 2020 at 09:45:13PM +0000, Mel Gorman wrote: > This could be watermark boosting run wild again. Can you test with > sysctl vm.watermark_boost_factor=0 or the following patch? (preferably > both to compare and contrast). I can test that, but something to note is that I've been doing equal testing with this on 4.4, which exhibits the same behavior, and that kernel doesn't have watermark boosting in it, as far as I can tell. I don't think what we're addressing here is a "bug", but rather something fundamental about how we've been thinking about kswapd lifetime. The argument here is that it's not coherent to be letting kswapd run as it does, and instead gating it on outstanding allocation requests provides much more reasonable behavior, given real workloads and use patterns. Does that make sense and seem reasonable? Sultan