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=-2.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, URIBL_DBL_ABUSE_MALW,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 C919CC33CB3 for ; Wed, 29 Jan 2020 01:08:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A95DC205F4 for ; Wed, 29 Jan 2020 01:08:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726833AbgA2BIe (ORCPT ); Tue, 28 Jan 2020 20:08:34 -0500 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:43818 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726422AbgA2BIe (ORCPT ); Tue, 28 Jan 2020 20:08:34 -0500 Received: from dread.disaster.area (pa49-195-111-217.pa.nsw.optusnet.com.au [49.195.111.217]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id EE9ED3A2496; Wed, 29 Jan 2020 12:08:30 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1iwbqH-0005zH-9B; Wed, 29 Jan 2020 12:08:29 +1100 Date: Wed, 29 Jan 2020 12:08:29 +1100 From: Dave Chinner To: Matthew Wilcox Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 11/12] fuse: Convert from readpages to readahead Message-ID: <20200129010829.GK18610@dread.disaster.area> References: <20200125013553.24899-1-willy@infradead.org> <20200125013553.24899-12-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200125013553.24899-12-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=LYdCFQXi c=1 sm=1 tr=0 a=0OveGI8p3fsTA6FL6ss4ZQ==:117 a=0OveGI8p3fsTA6FL6ss4ZQ==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=Jdjhy38mL1oA:10 a=JfrnYn6hAAAA:8 a=7-415B0cAAAA:8 a=XQoKVZl3_x8TtcCbSDwA:9 a=dkzf7bQtNeN5L-sv:21 a=BzqqMxnNl6DEKTpg:21 a=CjuIK1q_8ugA:10 a=WSd5SQCJy8UA:10 a=1CNFftbPRP8L7MoqJWF3:22 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 24, 2020 at 05:35:52PM -0800, Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" > > Use the new readahead operation in fuse. Switching away from the > read_cache_pages() helper gets rid of an implicit call to put_page(), > so we can get rid of the get_page() call in fuse_readpages_fill(). > We can also get rid of the call to fuse_wait_on_page_writeback() as > this page is newly allocated and so cannot be under writeback. > > Signed-off-by: Matthew Wilcox (Oracle) ..... > @@ -968,19 +962,24 @@ static int fuse_readpages(struct file *file, struct address_space *mapping, > data.max_pages = min_t(unsigned int, nr_pages, fc->max_pages); > ; > data.ia = fuse_io_alloc(NULL, data.max_pages); > - err = -ENOMEM; > if (!data.ia) > goto out; > > - err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data); > - if (!err) { > - if (data.ia->ap.num_pages) > - fuse_send_readpages(data.ia, file); > - else > - fuse_io_free(data.ia); > + while (nr_pages--) { > + struct page *page = readahead_page(mapping, start++); > + int err = fuse_readpages_fill(&data, page); > + > + if (!err) > + continue; > + nr_pages++; > + goto out; > } That's some pretty convoluted logic. Perhaps: for (; nr_pages > 0 ; nr_pages--) { struct page *page = readahead_page(mapping, start++); if (fuse_readpages_fill(&data, page)) goto out; } -Dave. -- Dave Chinner david@fromorbit.com