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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 C96A4C07E99 for ; Mon, 5 Jul 2021 18:45:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 64CD96196C for ; Mon, 5 Jul 2021 18:45:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64CD96196C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 135BA8D0002; Mon, 5 Jul 2021 14:45:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0BF3B8D0001; Mon, 5 Jul 2021 14:45:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E7A5B8D0002; Mon, 5 Jul 2021 14:45:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0039.hostedemail.com [216.40.44.39]) by kanga.kvack.org (Postfix) with ESMTP id BBB158D0001 for ; Mon, 5 Jul 2021 14:45:48 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 356B221967 for ; Mon, 5 Jul 2021 18:45:48 +0000 (UTC) X-FDA: 78329413176.02.7E2184C Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf19.hostedemail.com (Postfix) with ESMTP id 5B6B6B0000AD for ; Mon, 5 Jul 2021 18:45:47 +0000 (UTC) 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=aNDwCscw1p86DkXqINJ193YMMwMojg7IqAtfTHOFrf0=; b=tli0JQf63aKNQuU6V30vDNoLKW xs1PRFkoJOOygR1Pe/ZKjRhuqlwLDKBN6y1ULUtJb/dYAbDQRHxf9AgySXqDNdzbFgtk8EDNx+JqV iO7ICp+tFdRpf1XWxhgO2SAOSEG8V0KORR1aUAAh6ROogwS3XXW0GzzsqGrRYRkjIA/dwN5XJRFgO DM6jIV+NFd2QqIpBA+rjPQS2f2455MclI6qONorqe5aHu8DjB3D4PlHvSMDCAVgzUNz+kAKyzX92g b13se+6qajfCbSwFF1hA9kH/PbvTj34O0SD3hPjiWrz/IL2Quv0N+M8pd9z2xTXqmep1hBEKHyPM8 sX/mjbTA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m0Taw-00AW2c-IU; Mon, 05 Jul 2021 18:45:30 +0000 Date: Mon, 5 Jul 2021 19:45:26 +0100 From: Matthew Wilcox To: Jaegeuk Kim Cc: Chao Yu , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mm@kvack.org, Mel Gorman Subject: Re: [f2fs-dev] [PATCH] f2fs: initialize page->private when using for our internal use Message-ID: References: <20210705052216.831989-1-jaegeuk@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 5B6B6B0000AD X-Stat-Signature: rinb1sdysy5qs8az4wrya81153n1egn6 Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=tli0JQf6; dmarc=none; spf=none (imf19.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-HE-Tag: 1625510747-992035 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, Jul 05, 2021 at 11:04:21AM -0700, Jaegeuk Kim wrote: > On 07/05, Matthew Wilcox wrote: > > I think freshly allocated pages have a page->private of 0. ie this > > code in mm/page_alloc.c: > > > > page = rmqueue(ac->preferred_zoneref->zone, zone, order, > > gfp_mask, alloc_flags, ac->migratetype); > > if (page) { > > prep_new_page(page, order, gfp_mask, alloc_flags); > > > > where prep_new_page() calls post_alloc_hook() which contains: > > set_page_private(page, 0); > > Hmm, I can see it in 4.14 and 5.10 kernel. > > The trace is on: > > 30875 [ 1065.118750] c3 87 f2fs_migrate_page+0x354/0x45c > 30876 [ 1065.123872] c3 87 move_to_new_page+0x70/0x30c > 30877 [ 1065.128813] c3 87 migrate_pages+0x3a0/0x964 > 30878 [ 1065.133583] c3 87 compact_zone+0x608/0xb04 > 30879 [ 1065.138257] c3 87 kcompactd+0x378/0x4ec > 30880 [ 1065.142664] c3 87 kthread+0x11c/0x12c > 30881 [ 1065.146897] c3 87 ret_from_fork+0x10/0x18 > > It seems compaction_alloc() gets a free page which doesn't reset the fields? I'm not really familiar with the compaction code. Mel, I see a call to post_alloc_hook() in split_map_pages(). Are there other ways of getting the compaction code to allocate a page which don't go through split_map_pages()?