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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 7ADDEC35242 for ; Tue, 11 Feb 2020 04:52:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DF062072C for ; Tue, 11 Feb 2020 04:52:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728158AbgBKEwg (ORCPT ); Mon, 10 Feb 2020 23:52:36 -0500 Received: from mail104.syd.optusnet.com.au ([211.29.132.246]:44681 "EHLO mail104.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727121AbgBKEwg (ORCPT ); Mon, 10 Feb 2020 23:52:36 -0500 Received: from dread.disaster.area (pa49-179-138-28.pa.nsw.optusnet.com.au [49.179.138.28]) by mail104.syd.optusnet.com.au (Postfix) with ESMTPS id 11F74820924; Tue, 11 Feb 2020 15:52:30 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1j1NXC-0005dw-7j; Tue, 11 Feb 2020 15:52:30 +1100 Date: Tue, 11 Feb 2020 15:52:30 +1100 From: Dave Chinner To: Matthew Wilcox Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, ocfs2-devel@oss.oracle.com, linux-xfs@vger.kernel.org Subject: Re: [PATCH v5 04/13] mm: Add readahead address space operation Message-ID: <20200211045230.GD10776@dread.disaster.area> References: <20200211010348.6872-1-willy@infradead.org> <20200211010348.6872-5-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200211010348.6872-5-willy@infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=W5xGqiek c=1 sm=1 tr=0 a=zAxSp4fFY/GQY8/esVNjqw==:117 a=zAxSp4fFY/GQY8/esVNjqw==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=l697ptgUJYAA:10 a=JfrnYn6hAAAA:8 a=7-415B0cAAAA:8 a=TWVYvH7QqZ0YkocKP0UA:9 a=CjuIK1q_8ugA:10 a=1CNFftbPRP8L7MoqJWF3:22 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Feb 10, 2020 at 05:03:39PM -0800, Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" > > This replaces ->readpages with a saner interface: > - Return void instead of an ignored error code. > - Pages are already in the page cache when ->readahead is called. > - Implementation looks up the pages in the page cache instead of > having them passed in a linked list. > > Signed-off-by: Matthew Wilcox (Oracle) .... > > +/* > + * Readahead is of a block of consecutive pages. > + */ > +struct readahead_control { > + struct file *file; > + struct address_space *mapping; > +/* private: use the readahead_* accessors instead */ > + pgoff_t start; > + unsigned int nr_pages; > + unsigned int batch_count; > +}; > + > +static inline struct page *readahead_page(struct readahead_control *rac) > +{ > + struct page *page; > + > + if (!rac->nr_pages) > + return NULL; > + > + page = xa_load(&rac->mapping->i_pages, rac->start); > + VM_BUG_ON_PAGE(!PageLocked(page), page); > + rac->batch_count = hpage_nr_pages(page); > + rac->start += rac->batch_count; There's no mention of large page support in the patch description and I don't recall this sort of large page batching in previous iterations. This seems like new functionality to me, not directly related to the initial ->readahead API change? What have I missed? Cheers, Dave. -- Dave Chinner david@fromorbit.com