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,URIBL_BLOCKED,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 8D209C432C1 for ; Tue, 24 Sep 2019 19:55:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3BC87214DA for ; Tue, 24 Sep 2019 19:55:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3BC87214DA 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 AE5C06B000A; Tue, 24 Sep 2019 15:55:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A96DA6B000C; Tue, 24 Sep 2019 15:55:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9AC3B6B000D; Tue, 24 Sep 2019 15:55:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 73A066B000A for ; Tue, 24 Sep 2019 15:55:14 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 1793C181AC9B4 for ; Tue, 24 Sep 2019 19:55:14 +0000 (UTC) X-FDA: 75970868148.17.class63_84f30d1961025 X-HE-Tag: class63_84f30d1961025 X-Filterd-Recvd-Size: 3425 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Tue, 24 Sep 2019 19:55:13 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 21A17ADE0; Tue, 24 Sep 2019 19:55:12 +0000 (UTC) Subject: Re: incoming To: Michal Hocko , Andrew Morton Cc: Linus Torvalds , David Rientjes , Andrea Arcangeli , mm-commits@vger.kernel.org, Linux-MM References: <20190923153142.a7a7590798baebd3e1531083@linux-foundation.org> <20190923213153.62d56ab13a655aa7e2a583af@linux-foundation.org> <20190924074843.GC23050@dhcp22.suse.cz> From: Vlastimil Babka Message-ID: Date: Tue, 24 Sep 2019 21:55:09 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190924074843.GC23050@dhcp22.suse.cz> 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 9/24/19 9:48 AM, Michal Hocko wrote: > On Mon 23-09-19 21:31:53, Andrew Morton wrote: >> On Mon, 23 Sep 2019 17:55:24 -0700 Linus Torvalds >> wrote: >> >>> On Mon, Sep 23, 2019 at 3:31 PM Andrew Morton >>> wrote: >>>> >>>> - almost all of -mm, as below. >>> >>> I was hoping that we could at least test the THP locality thing? >>> Is it in your queue at all, or am I supposed to just do it >>> myself? >>> >> >> Confused. I saw a privately emailed patch from David which nobody >> seems to have tested yet. I parked that for consideration after >> -rc1. Or are you referring to something else? >> >> This thing keeps stalling. It would be nice to push this along and >> get something nailed down which we can at least get into 5.4-rc, >> perhaps with a backport-this tag? > > The patch proposed by David is really non trivial wrt. potential > side effects. I have provided my review feedback [1] and it didn't > get any reaction. I really believe that we need to debug this > properly. A reproducer would be useful for others to work on that. > > There is a more fundamental problem here and we need to address it > rather than to duck tape it and whack a mole afterwards. I believe we found a problem when investigating over-reclaim in this thread [1] where it seems madvised THP allocation attempt can result in 4MB reclaimed, if there is a small zone such as ZONE_DMA on the node. As it happens, the patch "[patch 090/134] mm, reclaim: make should_continue_reclaim perform dryrun detection" in Andrew's pile should change this 4MB to 32 pages reclaimed (as a side-effect), but that has to be tested. I'm also working on a patch to not reclaim even those few pages. Of course there might be more fundamental issues with reclaim/compaction interaction, but this one seems to become hopefully clear now. [1] https://lore.kernel.org/linux-mm/4b4ba042-3741-7b16-2292-198c569da2aa@profihost.ag/ > [1] http://lkml.kernel.org/r/20190909193020.GD2063@dhcp22.suse.cz >