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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 2E826C3404C for ; Tue, 18 Feb 2020 20:49:29 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D1E8F2173E for ; Tue, 18 Feb 2020 20:49:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="OYgEBVV/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D1E8F2173E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48MXyt6241zDqdZ for ; Wed, 19 Feb 2020 07:49:26 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nvidia.com (client-ip=216.228.121.64; helo=hqnvemgate25.nvidia.com; envelope-from=jhubbard@nvidia.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=nvidia.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=nvidia.com header.i=@nvidia.com header.a=rsa-sha256 header.s=n1 header.b=OYgEBVV/; dkim-atps=neutral Received: from hqnvemgate25.nvidia.com (hqnvemgate25.nvidia.com [216.228.121.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48MXyk1rRLzDqZT for ; Wed, 19 Feb 2020 07:49:16 +1100 (AEDT) Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 18 Feb 2020 12:48:40 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Tue, 18 Feb 2020 12:49:11 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Tue, 18 Feb 2020 12:49:11 -0800 Received: from [10.110.48.28] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 18 Feb 2020 20:49:11 +0000 Subject: Re: [PATCH v6 00/19] Change readahead API To: Matthew Wilcox , References: <20200217184613.19668-1-willy@infradead.org> From: John Hubbard X-Nvconfidentiality: public Message-ID: <80d98657-2f93-da92-a541-707429a6fcdf@nvidia.com> Date: Tue, 18 Feb 2020 12:49:11 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200217184613.19668-1-willy@infradead.org> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1582058920; bh=sSzUuAsXGIrXy4vQ0zTAGyf0jed9sNlmwz2tpEx8I1w=; h=X-PGP-Universal:Subject:To:CC:References:From:X-Nvconfidentiality: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=OYgEBVV/ua9FohonQVxYl3qPPXVMYQG31aVJZXFPu7SkYOwxhtaZfQM11ZRWuKWRn lVI3HR/RIXFrZMOWjvHUihTcKXkE2jgWZqXXGCNxpXb3Nv2SKAT+FXp4fzmW9R+SbR +H8xokJDzpZ6UCukKlMzu/5eKP5axPGrm5jxpyyz73wcaxjN5ykeBaYI4TDMwgMSY8 xsZHrBQYyHRUHdXgYU3ZVNQuJpgqlmVcDrdSv4XqikXa55cxrAOxN2l1s5oRfr4SZG EEyk1LdZCMme+4QhBVN+8g/HUCynjQ8e9lz6/YoFujDdaTBOhd1TQ8nXhH+hrOTVqL JwGZHfev+XX/A== X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-mm@kvack.org, ocfs2-devel@oss.oracle.com, linux-ext4@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" On 2/17/20 10:45 AM, Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" > > This series adds a readahead address_space operation to eventually > replace the readpages operation. The key difference is that > pages are added to the page cache as they are allocated (and > then looked up by the filesystem) instead of passing them on a > list to the readpages operation and having the filesystem add > them to the page cache. It's a net reduction in code for each > implementation, more efficient than walking a list, and solves > the direct-write vs buffered-read problem reported by yu kuai at > https://lore.kernel.org/linux-fsdevel/20200116063601.39201-1-yukuai3@huawei.com/ > > The only unconverted filesystems are those which use fscache. > Their conversion is pending Dave Howells' rewrite which will make the > conversion substantially easier. Hi Matthew, I see that Dave Chinner is reviewing this series, but I'm trying out his recent advice about code reviews [1], and so I'm not going to read his comments first. So you may see some duplication or contradictions this time around. [1] Somewhere in this thread, "[LSF/MM/BPF TOPIC] FS Maintainers Don't Scale": https://lore.kernel.org/r/20200131052520.GC6869@magnolia thanks, -- John Hubbard NVIDIA > > v6: > - Name the private members of readahead_control with a leading underscore > (suggested by Christoph Hellwig) > - Fix whitespace in rst file > - Remove misleading comment in btrfs patch > - Add readahead_next() API and use it in iomap > - Add iomap_readahead kerneldoc. > - Fix the mpage_readahead kerneldoc > - Make various readahead functions return void > - Keep readahead_index() and readahead_offset() pointing to the start of > this batch through the body. No current user requires this, but it's > less surprising. > - Add kerneldoc for page_cache_readahead_limit > - Make page_idx an unsigned long, and rename it to just 'i' > - Get rid of page_offset local variable > - Add patch to call memalloc_nofs_save() before allocating pages (suggested > by Michal Hocko) > - Resplit a lot of patches for more logical progression and easier review > (suggested by John Hubbard) > - Added sign-offs where received, and I deemed still relevant > > v5 switched to passing a readahead_control struct (mirroring the > writepages_control struct passed to writepages). This has a number of > advantages: > - It fixes a number of bugs in various implementations, eg forgetting to > increment 'start', an off-by-one error in 'nr_pages' or treating 'start' > as a byte offset instead of a page offset. > - It allows us to change the arguments without changing all the > implementations of ->readahead which just call mpage_readahead() or > iomap_readahead() > - Figuring out which pages haven't been attempted by the implementation > is more natural this way. > - There's less code in each implementation. > > Matthew Wilcox (Oracle) (19): > mm: Return void from various readahead functions > mm: Ignore return value of ->readpages > mm: Use readahead_control to pass arguments > mm: Rearrange readahead loop > mm: Remove 'page_offset' from readahead loop > mm: rename readahead loop variable to 'i' > mm: Put readahead pages in cache earlier > mm: Add readahead address space operation > mm: Add page_cache_readahead_limit > fs: Convert mpage_readpages to mpage_readahead > btrfs: Convert from readpages to readahead > erofs: Convert uncompressed files from readpages to readahead > erofs: Convert compressed files from readpages to readahead > ext4: Convert from readpages to readahead > f2fs: Convert from readpages to readahead > fuse: Convert from readpages to readahead > iomap: Restructure iomap_readpages_actor > iomap: Convert from readpages to readahead > mm: Use memalloc_nofs_save in readahead path > > Documentation/filesystems/locking.rst | 6 +- > Documentation/filesystems/vfs.rst | 13 ++ > drivers/staging/exfat/exfat_super.c | 7 +- > fs/block_dev.c | 7 +- > fs/btrfs/extent_io.c | 46 ++----- > fs/btrfs/extent_io.h | 3 +- > fs/btrfs/inode.c | 16 +-- > fs/erofs/data.c | 39 ++---- > fs/erofs/zdata.c | 29 ++-- > fs/ext2/inode.c | 10 +- > fs/ext4/ext4.h | 3 +- > fs/ext4/inode.c | 23 ++-- > fs/ext4/readpage.c | 22 ++- > fs/ext4/verity.c | 35 +---- > fs/f2fs/data.c | 50 +++---- > fs/f2fs/f2fs.h | 5 +- > fs/f2fs/verity.c | 35 +---- > fs/fat/inode.c | 7 +- > fs/fuse/file.c | 46 +++---- > fs/gfs2/aops.c | 23 ++-- > fs/hpfs/file.c | 7 +- > fs/iomap/buffered-io.c | 118 +++++++---------- > fs/iomap/trace.h | 2 +- > fs/isofs/inode.c | 7 +- > fs/jfs/inode.c | 7 +- > fs/mpage.c | 38 ++---- > fs/nilfs2/inode.c | 15 +-- > fs/ocfs2/aops.c | 34 ++--- > fs/omfs/file.c | 7 +- > fs/qnx6/inode.c | 7 +- > fs/reiserfs/inode.c | 8 +- > fs/udf/inode.c | 7 +- > fs/xfs/xfs_aops.c | 13 +- > fs/zonefs/super.c | 7 +- > include/linux/fs.h | 2 + > include/linux/iomap.h | 3 +- > include/linux/mpage.h | 4 +- > include/linux/pagemap.h | 90 +++++++++++++ > include/trace/events/erofs.h | 6 +- > include/trace/events/f2fs.h | 6 +- > mm/internal.h | 8 +- > mm/migrate.c | 2 +- > mm/readahead.c | 184 +++++++++++++++++--------- > 43 files changed, 474 insertions(+), 533 deletions(-) > > > base-commit: 11a48a5a18c63fd7621bb050228cebf13566e4d8 >