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=-7.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 4496CC433B4 for ; Mon, 17 May 2021 19:41:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D04B961285 for ; Mon, 17 May 2021 19:41:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D04B961285 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4A8E26B0085; Mon, 17 May 2021 15:41:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 458A86B0087; Mon, 17 May 2021 15:41:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2AADC6B0088; Mon, 17 May 2021 15:41:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0173.hostedemail.com [216.40.44.173]) by kanga.kvack.org (Postfix) with ESMTP id E3B606B0085 for ; Mon, 17 May 2021 15:41:24 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 8133298A6 for ; Mon, 17 May 2021 19:41:24 +0000 (UTC) X-FDA: 78151742088.28.EFF275C Received: from mail-ej1-f45.google.com (mail-ej1-f45.google.com [209.85.218.45]) by imf08.hostedemail.com (Postfix) with ESMTP id 3766280192F3 for ; Mon, 17 May 2021 19:41:21 +0000 (UTC) Received: by mail-ej1-f45.google.com with SMTP id k14so7429948eji.2 for ; Mon, 17 May 2021 12:41:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yXa/Lm0suCl/5c57+vWfzuJ0nIP5bhlu8lJSFWkdrv8=; b=WSduR54CQpT0eAZStLjK9HbqVDBbUEgAkAjcMlUQCnXWK9SG3yY3qCeDbctPh0+XkC rNBCqo5BT/Zk63QGr7nIM3iPsiWMsvqy112Yf/cwtEJwmDY0ipOlxYC1xDX4xfvPNDBZ Vdz12P2rUSZiixxROKQZ8OHYprGu32tcE1nwZ6qwiRUo7+wNzZkBRLcjoz18STfK+wZB a21zgdq3fEJdrMCBlsdUVdOTc7I+uvwAk+KwXbKtQy4MtRcTHIYN2aKPn8vKDQTh6f/T Iuv1ZFYMl6tzXEUt0LS51E3qkpNEBj4BsL11Rway1HWQ/t9UueOsz84zOowmBXTW7AHB ACkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=yXa/Lm0suCl/5c57+vWfzuJ0nIP5bhlu8lJSFWkdrv8=; b=WcMExpmyDvFy9iYGrofxGOHikR+w4wFW5QVWORLbZtZM/B1yHj6J4FQzAZzcCa60L6 MAqvhr35D0QdrQOqsmEm7mNHIzBZwSucUhlQP2r5f17L0W0E3FNb5+Gc5vjA/fHvDATe Cebkj5pm98h+b7N7nKdo9erb9M0UeXc12W4Rw53sftm3HCCz6SXFlzC2afp3n8NXad/t Ztb7eDunmTlN1VHu4WF0KFA0szwL6G/jdPwvbnjVqDLk9ZkOsLhj6yhIchjwfSz4eHjZ xe2pzvleJ3FgMHUwJsP8jeEbMI4koNDPB4jj1epmeY1hkvDAkBNpiRGqWGaJeHsXlzTk 6PKA== X-Gm-Message-State: AOAM531Litf8pthgPL1WPi2HiasGHKMQwNsuArDtSzJCssTFUNo5sxlK F1yMRtYrGQCnp9II5mJDtFG4sHOs0fw8xMyXWBk= X-Google-Smtp-Source: ABdhPJyFcwx+LAv5N1H+8RwcM+ovypSsnjKzeZwOG0slZQVgpScQlcbUgcd70BoSRPNM8YYAa5YW0E4kLCKDe73qm28= X-Received: by 2002:a17:906:11c8:: with SMTP id o8mr1548021eja.499.1621280483076; Mon, 17 May 2021 12:41:23 -0700 (PDT) MIME-Version: 1.0 References: <20210413212416.3273-1-shy828301@gmail.com> <20210413212416.3273-4-shy828301@gmail.com> <20210517152721.GW3672@suse.de> In-Reply-To: <20210517152721.GW3672@suse.de> From: Yang Shi Date: Mon, 17 May 2021 12:41:11 -0700 Message-ID: Subject: Re: [v2 PATCH 3/7] mm: thp: refactor NUMA fault handling To: Mel Gorman Cc: "Kirill A. Shutemov" , Zi Yan , Michal Hocko , Huang Ying , Hugh Dickins , Gerald Schaefer , hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, Andrew Morton , Linux MM , linux-s390@vger.kernel.org, Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 3766280192F3 Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=WSduR54C; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf08.hostedemail.com: domain of shy828301@gmail.com designates 209.85.218.45 as permitted sender) smtp.mailfrom=shy828301@gmail.com X-Rspamd-Server: rspam03 X-Stat-Signature: 1yz87s5ursynkqbg8wym5z789hbrsope X-HE-Tag: 1621280481-147808 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, May 17, 2021 at 8:27 AM Mel Gorman wrote: > > On Tue, Apr 13, 2021 at 02:24:12PM -0700, Yang Shi wrote: > > When the THP NUMA fault support was added THP migration was not supported yet. > > So the ad hoc THP migration was implemented in NUMA fault handling. Since v4.14 > > THP migration has been supported so it doesn't make too much sense to still keep > > another THP migration implementation rather than using the generic migration > > code. > > > > This patch reworked the NUMA fault handling to use generic migration implementation > > to migrate misplaced page. There is no functional change. > > > > After the refactor the flow of NUMA fault handling looks just like its > > PTE counterpart: > > Acquire ptl > > Prepare for migration (elevate page refcount) > > Release ptl > > Isolate page from lru and elevate page refcount > > Migrate the misplaced THP > > > > If migration is failed just restore the old normal PMD. > > > > In the old code anon_vma lock was needed to serialize THP migration > > against THP split, but since then the THP code has been reworked a lot, > > it seems anon_vma lock is not required anymore to avoid the race. > > > > The page refcount elevation when holding ptl should prevent from THP > > split. > > > > Use migrate_misplaced_page() for both base page and THP NUMA hinting > > fault and remove all the dead and duplicate code. > > > > Signed-off-by: Yang Shi > > I did not spot any big problems and FWIW, the series overall passed a > series of tests that exercise NUMA balancing migrations so... > > Acked-by: Mel Gorman Thanks a lot for testing and reviewing the series. > > -- > Mel Gorman > SUSE Labs