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 lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C218CC77B7A for ; Tue, 23 May 2023 03:31:38 +0000 (UTC) Received: from [127.0.0.1] (helo=sfs-ml-2.v29.lw.sourceforge.com) by sfs-ml-2.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1q1IkK-00072R-9T; Tue, 23 May 2023 03:31:36 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1q1IkC-00072F-65 for linux-f2fs-devel@lists.sourceforge.net; Tue, 23 May 2023 03:31:31 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; 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:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=/hND79jypjGMxrh+L0AHfmoXlB7jfnZF846f0hmvk3s=; b=hgJ3wX0NE77KzfbMgEDZhGME7o o+ANtI3+C9txyFHoacTotazhDe+URi1Xwy5agbND/PqCQBmm/KznpT63vqOlOpQzdNdkeslM63T/6 EpibaURFwkUV4P92MUmXQdPxLyYNUV8sD6Lxj+Np1NgQUXJiGjkMrP8ZzjD+jZEU2NlU=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; 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:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=/hND79jypjGMxrh+L0AHfmoXlB7jfnZF846f0hmvk3s=; b=NN7saOTmdx2zeEIux9PRQK4ZqP 6ElbGZlb66dwE+qXjJ0lieNIQxTwN7CIbQ0wli7cIKc1FiZpzMYcj85aeXFAp/UufFUT/T+rbdgrA RU8graY792oeBiGFfIilJrGZpdFabuL0jQaCuUeNBYJKHn+wE1D41HVyE6KAl93RkkDA=; Received: from [90.155.50.34] (helo=casper.infradead.org) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1q1Ik5-00061u-Lo for linux-f2fs-devel@lists.sourceforge.net; Tue, 23 May 2023 03:31:27 +0000 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=/hND79jypjGMxrh+L0AHfmoXlB7jfnZF846f0hmvk3s=; b=HROkOeYJgsW515w412weVmp0+i YEdCM3PRHJ8yLIzdBSb+Xne+pGdopXsi8JnT0CNNfg9oYv05lkYp5Nceqaag93z1O8A122qkxCVFv +izmJgPDGdRSRSfuroAjrwUvFuFU9Sr+1LDaSOnQuHT4rkaVFrGW9ZqvWG2nbNXKaUr5oZDVJK11I RyvLNOj1PcX4LwBEV/FegrIgbBdhvp7j2y31h8Wy7rSvHujrlGbNAYVSA0t7gLYx6nDhZYo2aTnwG 2e2CzusZB4FwcCAcoisC1TopNtNPBuTbaa+4Xz1KrGZTS3PUwYf30EPvOgjalWOatycvM59In4SD4 sazxHniQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1q1Ijb-009k51-9e; Tue, 23 May 2023 03:30:51 +0000 Date: Tue, 23 May 2023 04:30:51 +0100 From: Matthew Wilcox To: "Darrick J. Wong" Message-ID: References: <20230519093521.133226-1-hch@lst.de> <20230519093521.133226-9-hch@lst.de> <20230523010627.GD11598@frogsfrogsfrogs> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230523010627.GD11598@frogsfrogsfrogs> X-Headers-End: 1q1Ik5-00061u-Lo Subject: Re: [f2fs-dev] [PATCH 08/13] iomap: assign current->backing_dev_info in iomap_file_buffered_write X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: NeilBrown , linux-mm@kvack.org, Christoph Hellwig , Andreas Gruenbacher , Miklos Szeredi , cluster-devel@redhat.com, Ilya Dryomov , linux-ext4@vger.kernel.org, linux-nfs@vger.kernel.org, linux-block@vger.kernel.org, Damien Le Moal , Alexander Viro , Jaegeuk Kim , ceph-devel@vger.kernel.org, Xiubo Li , Trond Myklebust , Jens Axboe , Christian Brauner , Theodore Ts'o , "open list:F2FS FILE SYSTEM" , linux-xfs@vger.kernel.org, Anna Schumaker , linux-fsdevel@vger.kernel.org, Andrew Morton Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Mon, May 22, 2023 at 06:06:27PM -0700, Darrick J. Wong wrote: > On Fri, May 19, 2023 at 11:35:16AM +0200, Christoph Hellwig wrote: > > Move the assignment to current->backing_dev_info from the callers into > > iomap_file_buffered_write to reduce boiler plate code and reduce the > > scope to just around the page dirtying loop. > > > > Note that zonefs was missing this assignment before. > > I'm still wondering (a) what the hell current->backing_dev_info is for, > and (b) if we need it around the iomap_unshare operation. > > $ git grep current..backing_dev_info [results show it only set, never used] > > AFAICT nobody uses it at all? Unless there's some bizarre user that > isn't extracting it from @current? > > Oh, hey, new question (c) isn't this set incorrectly for xfs realtime > files? Some git archaelogy ... This was first introduced in commit 2f45a06517a62 (in the linux-fullhistory tree) in 2002 by one Andrew Morton. At the time, it added this check to the page scanner: + if (page->pte.direct || + page->mapping->backing_dev_info == + current->backing_dev_info) { + wait_on_page_writeback(page); + } AFAICT (the code went through some metamorphoses in the intervening twenty years), the last use of it ended up in current_may_throttle(), and it was removed in March 2022 by Neil Brown in commit b9b1335e6403. Since then, there have been no users of task->backing_dev_info, and I'm pretty sure it can go away. _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel