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 AE739C433FE for ; Sat, 28 May 2022 06:12:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 353EB8D0003; Sat, 28 May 2022 02:12:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 302FF8D0001; Sat, 28 May 2022 02:12:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1F0A08D0003; Sat, 28 May 2022 02:12:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 0D7128D0001 for ; Sat, 28 May 2022 02:12:31 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id CCF22341DF for ; Sat, 28 May 2022 06:12:30 +0000 (UTC) X-FDA: 79514132460.30.122EF70 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf04.hostedemail.com (Postfix) with ESMTP id 1CE7140047 for ; Sat, 28 May 2022 06:12:12 +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=XRCyrfsOL2PXgIyjGTvYC1oF+7LmRBgFYCVBlEy3SLM=; b=JCJwFEd4qJ37PkLpdR/dcR6Hyi U/gUarqXwImt2//XtGeUXO5SC78Z4QRBmgIb5HCbIB4fXOhV4b3Cjz01ZjPqxqNSCTAdiX4x1dsip VtwhHFCiSQme/BZKiP5sJ0HwAUzW3LNqhHprG4nafN8t1RTJPpwwhxlHfdjz36PCDTN2NBLh1NPp2 xBVKYnMrb27Yn+B/Mo597bALnMCN0Q8JgfSXE5HFzCnl9pVR3dBAFslSC6qPCPEKMF4dpaxwZwrkz 5hYqYJjPUyvywBTL+IqzxD5xhjZlbDDEbtPmzNZPaZCa644NPPp65nuVU4dwDQyD3vNO+gf4c+Fq5 Y+A2L+xA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nupgZ-001XvQ-Qt; Sat, 28 May 2022 06:12:27 +0000 Date: Fri, 27 May 2022 23:12:27 -0700 From: Christoph Hellwig To: "Matthew Wilcox (Oracle)" Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 00/24] Begin removing PageError Message-ID: References: <20220527155036.524743-1-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220527155036.524743-1-willy@infradead.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Stat-Signature: sdmif5kckrkbzbjwpfuyzuf6hjprnkrd Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=JCJwFEd4; dmarc=none; spf=none (imf04.hostedemail.com: domain of BATV+c5e11ba0f85895bf2855+6852+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+c5e11ba0f85895bf2855+6852+infradead.org+hch@bombadil.srs.infradead.org X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 1CE7140047 X-HE-Tag: 1653718332-658534 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 Fri, May 27, 2022 at 04:50:12PM +0100, Matthew Wilcox (Oracle) wrote: > After this series, there are some places which still use it. Lots of > the converted places are trivial -- they should have been checking the > uptodate flag. The trickiest are the ones which have multiple steps > and signal "hey, something went wrong with one step in the read of this > page/folio" by setting the error flag. How many of those do we have left, and how many of those can't be changed to just return them through errors or other on-stack means? > I'm thinking about (ab)using PageChecked == PG_owner_priv_1 for this > purpose. It'd be nice to be able to use page->private for this, but > that's not always available. I know some filesystems already ascribe > a meaning to PG_owner_priv_1, but those can be distinguished by whether > the uptodate flag is set. I suspect what to do will be very ad-hoc depending on the actual user. The first priority is probably to isolate PageError so that it is only used for that kind of communication insid a single file system so that all the generic uses can go away.