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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 0DE73C33CB1 for ; Tue, 14 Jan 2020 08:06:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CD9212187F for ; Tue, 14 Jan 2020 08:06:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD9212187F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 62C448E0006; Tue, 14 Jan 2020 03:06:01 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5DC858E0003; Tue, 14 Jan 2020 03:06:01 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 519A58E0006; Tue, 14 Jan 2020 03:06:01 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0112.hostedemail.com [216.40.44.112]) by kanga.kvack.org (Postfix) with ESMTP id 3C9A58E0003 for ; Tue, 14 Jan 2020 03:06:01 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id F412B8248047 for ; Tue, 14 Jan 2020 08:06:00 +0000 (UTC) X-FDA: 76375506480.16.join60_175b8f9a9e857 X-HE-Tag: join60_175b8f9a9e857 X-Filterd-Recvd-Size: 3033 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf24.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Jan 2020 08:06:00 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id A8D9EADDC; Tue, 14 Jan 2020 08:05:58 +0000 (UTC) Subject: Re: [patch 01/11] mm, thp: tweak reclaim/compaction effort of local-only and all-node allocations To: Linus Torvalds , Andrew Morton Cc: David Rientjes , Michal Hocko , Mel Gorman , "Kirill A . Shutemov" , Andrea Arcangeli , Linux-MM , mm-commits@vger.kernel.org References: <20200113162831.f7d69e11e9e673c40005c9b0@linux-foundation.org> <20200114002904.h9bSo%akpm@linux-foundation.org> From: Vlastimil Babka Message-ID: <90d8ba5d-9462-bcfa-3e93-2ca53f1010ba@suse.cz> Date: Tue, 14 Jan 2020 09:05:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 1/14/20 3:16 AM, Linus Torvalds wrote: > On Mon, Jan 13, 2020 at 4:29 PM Andrew Morton wrote: >> >> From: Vlastimil Babka >> Subject: mm, thp: tweak reclaim/compaction effort of local-only and all-node allocations > > I absolutely _detest_ how we've had this pattern of trying to change > the THP logic in a late -rc game. > > Considering how unsuccessful some of the earlier attempts have been, > late -rc kernels really are *not* the time to make changes like this. Agreed, myself would have been much more comfortable in rc1. > I'm going to take it this time, but Thanks. > (a) I'm going to revert *immediately* if anybody even peeps about the > new behavior > > (b) I want this to stop. Andrew - send THP "tweaks" during the merge > window, and not like some late-rc "fixes", when there are absolutely > _zero_ performance numbers or anything else critical associated with > the patch. > > IOW, there is a decided lack of "bugfix" here. And if there actually > _were_ performance numbers, they should have been in the explanation. FWIW Mel did some tests [1] which showed some improvement to THP success rate and no significant extra swapping that was feared. We didn't get confirmation from Andrea about his real life workloads though. [1] https://lore.kernel.org/linux-mm/20191113112042.GG28938@suse.de/ > So stop randomly messing with the THP allocation code, since it's > _known_ to be fragile with subtle side effects. > > Linus >