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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C022C433EF for ; Mon, 24 Jan 2022 07:31:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C9B396B0083; Mon, 24 Jan 2022 02:31:20 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C23016B0085; Mon, 24 Jan 2022 02:31:20 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AEB376B0087; Mon, 24 Jan 2022 02:31:20 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0082.hostedemail.com [216.40.44.82]) by kanga.kvack.org (Postfix) with ESMTP id A067D6B0083 for ; Mon, 24 Jan 2022 02:31:20 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 5134E8249980 for ; Mon, 24 Jan 2022 07:31:20 +0000 (UTC) X-FDA: 79064359920.13.152445F Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf05.hostedemail.com (Postfix) with ESMTP id DCE9A100033 for ; Mon, 24 Jan 2022 07:31:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=wm9QWOWAoKnKE8jbHgQf6O6XgO5ODHRTGPygTipLI00=; b=ZhSOw6y0O+aXYSf2WxdcCVJjgg +ZN8avm2joj0S5DBp8UHCsG/XhcTwW86PbqDoGOj9MDtZ5b9GlDCnjYLHGbEfmOT2Qs+yrtb47ihy N1pmUz4y0aSlHckLeL2GtCuEdYduiKRlfsyB9sCAf5mMRxZkjFEYh6GZwlqD3o5xPS1q8hJOsFdsY kComh8k4+fsuflvjI+t0qG6EZuujnrUKInbRApEPjSiqrosquB3RYdhbl0/QMbWmG+luKBpQCYuyp 6rcDu0RPp8q5dew29Bes1s0C3RbpuncnXVAFbtG4QJ5N84jhRvxI/1k2N8q4lrn4492kH8ISZej2B sCSHorCA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nBton-002UYH-Sm; Mon, 24 Jan 2022 07:31:13 +0000 Date: Sun, 23 Jan 2022 23:31:13 -0800 From: Christoph Hellwig To: NeilBrown Cc: Trond Myklebust , Anna Schumaker , Chuck Lever , Andrew Morton , Mel Gorman , Christoph Hellwig , David Howells , linux-nfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 05/23] MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space Message-ID: References: <164299573337.26253.7538614611220034049.stgit@noble.brown> <164299611276.26253.11555458501911153645.stgit@noble.brown> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <164299611276.26253.11555458501911153645.stgit@noble.brown> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Stat-Signature: ofxm8inb83uirrnaeymt1cezc76xsua9 Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=ZhSOw6y0; spf=none (imf05.hostedemail.com: domain of BATV+b18af077b488c69bdec9+6728+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+b18af077b488c69bdec9+6728+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: DCE9A100033 X-HE-Tag: 1643009479-888629 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, Jan 24, 2022 at 02:48:32PM +1100, NeilBrown wrote: > If swap-out is using filesystem operations (SWP_FS_OPS), then it is not > safe to enter the FS for reclaim. > So only down-grade the requirement for swap pages to __GFP_IO after > checking that SWP_FS_OPS are not being used. > > This makes the calculation of "may_enter_fs" slightly more complex, so > move it into a separate function. with that done, there is little value > in maintaining the bool variable any more. So replace the > may_enter_fs variable with a may_enter_fs() function. This removes any > risk for the variable becoming out-of-date. Looks good, Reviewed-by: Christoph Hellwig