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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59F74C433EF for ; Tue, 16 Nov 2021 19:07:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D0B2B6321A for ; Tue, 16 Nov 2021 19:07:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D0B2B6321A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 0C6BB6B007B; Tue, 16 Nov 2021 14:07:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 077306B007D; Tue, 16 Nov 2021 14:07:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E809F6B007E; Tue, 16 Nov 2021 14:07:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0217.hostedemail.com [216.40.44.217]) by kanga.kvack.org (Postfix) with ESMTP id D8D916B007B for ; Tue, 16 Nov 2021 14:07:26 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 927A21828C610 for ; Tue, 16 Nov 2021 19:07:26 +0000 (UTC) X-FDA: 78815726892.04.9A855A2 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf10.hostedemail.com (Postfix) with ESMTP id BCB3661085B7 for ; Tue, 16 Nov 2021 18:26:37 +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=4es8FO5SJaQGq2UgE1ci1YHP56WQQ2cHosypX0fQUds=; b=shYGA2EQWsHmDyFu5BR3rthX+m fINS2KeKdL7lH1ZuCThcNqv/nOwm2fJRlL9T1/yiFgPOirEIettm4ER3zGz8PChISJW4mo99JhmZn 4r+wuekG50XBiCggC36fX8KPX70E3L3aqbkBnfuQ8VD0SFV9KDM8w+pyyAXbKVkgFTq1obxYW2Ogc B73HKBgKiSwnaWTDTJUZ2FdAwBRWPOzQjWbaillvxKqRzIWMHNZGGPBD18UeHZ/loXpIQtxRk4p/w 8Dnv5a0szw+Rj/ZtgLfIkT7zREGg5Gnz7Th4TvVxX65QFkudNJd4n5Ac4AhVP9mSujhqbrroDhVo2 Ch4Cr1HA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mmttb-000kGz-Tl; Tue, 16 Nov 2021 08:32:51 +0000 Date: Tue, 16 Nov 2021 00:32:51 -0800 From: Christoph Hellwig To: NeilBrown Cc: Trond Myklebust , Anna Schumaker , Chuck Lever , Andrew Morton , Mel Gorman , linux-nfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 03/13] MM: reclaim mustn't enter FS for swap-over-NFS Message-ID: References: <163702956672.25805.16457749992977493579.stgit@noble.brown> <163703064452.25805.16932817889703270242.stgit@noble.brown> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <163703064452.25805.16932817889703270242.stgit@noble.brown> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: BCB3661085B7 X-Stat-Signature: 3fgmkuqtb7fj6w4f1wn88w64df198335 Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=shYGA2EQ; dmarc=none; spf=none (imf10.hostedemail.com: domain of BATV+fc0a9848db96d791f48c+6659+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+fc0a9848db96d791f48c+6659+infradead.org+hch@bombadil.srs.infradead.org X-HE-Tag: 1637087197-560102 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 Tue, Nov 16, 2021 at 01:44:04PM +1100, NeilBrown wrote: > + /* ->flags can be updated non-atomicially (scan_swap_map_slots), > + * but that will never affect SWP_FS_OPS, so the data_race > + * is safe. > + */ > may_enter_fs = (sc->gfp_mask & __GFP_FS) || > + (PageSwapCache(page) && > + !data_race(page_swap_info(page)->flags & SWP_FS_OPS) && > + (sc->gfp_mask & __GFP_IO)); You might want to move the comment and SWP_FS_OPS into a little inline helper. That makes it a lot more readable and also avoids the overly long line in the second hunk.