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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 2F7A4C11D0C for ; Thu, 20 Feb 2020 15:49:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E0E4224656 for ; Thu, 20 Feb 2020 15:49:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IvfiRDAg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E0E4224656 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 93F0A6B0003; Thu, 20 Feb 2020 10:49:14 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 916A26B0006; Thu, 20 Feb 2020 10:49:14 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 82B646B0007; Thu, 20 Feb 2020 10:49:14 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0098.hostedemail.com [216.40.44.98]) by kanga.kvack.org (Postfix) with ESMTP id 6B5006B0003 for ; Thu, 20 Feb 2020 10:49:14 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 14FC7180AD80F for ; Thu, 20 Feb 2020 15:49:14 +0000 (UTC) X-FDA: 76510939428.22.sound91_6daa1c96c1f0c X-HE-Tag: sound91_6daa1c96c1f0c X-Filterd-Recvd-Size: 6484 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Thu, 20 Feb 2020 15:49:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=7g85dNFHzF/fBL9mBZEQmhhyGBt/I3eV6QDa1nqOoos=; b=IvfiRDAgsZm0A9toDG9h8/8uAA KbYE+2vwy69rK19el39MgBf1l8Zem4llp2DdKaoFaLssf9HIohLYHoTx3yLoNphAL3B4OW2a3TqaQ APCgNVOUP8g+TxCalGnh8EI42nuAFMrX9cE9OX4zt+hbxXsL+0/NJcWdbqDoY7JufhSpOQo1f3wfV fkGP7cFp6XG76uPR5pdo5zTHChgWTTy+EJ1gchARS9Yknu04TeExGo+IFyyvEtOZG64LP3eWb02w2 WqzkFJXmy1vTEJVCbYJfZJxS0vJbpIavKWbr+CHQ6AfPHzIjCreIBNVndGPsy/9SPIGuaAwSRaJS4 bnKVMu2g==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j4o4e-0005Ks-N5; Thu, 20 Feb 2020 15:49:12 +0000 Date: Thu, 20 Feb 2020 07:49:12 -0800 From: Christoph Hellwig 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 v7 22/24] iomap: Convert from readpages to readahead Message-ID: <20200220154912.GC19577@infradead.org> References: <20200219210103.32400-1-willy@infradead.org> <20200219210103.32400-23-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200219210103.32400-23-willy@infradead.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html 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 Wed, Feb 19, 2020 at 01:01:01PM -0800, Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" > > Use the new readahead operation in iomap. Convert XFS and ZoneFS to > use it. > > Signed-off-by: Matthew Wilcox (Oracle) > --- > fs/iomap/buffered-io.c | 90 +++++++++++++++--------------------------- > fs/iomap/trace.h | 2 +- > fs/xfs/xfs_aops.c | 13 +++--- > fs/zonefs/super.c | 7 ++-- > include/linux/iomap.h | 3 +- > 5 files changed, 41 insertions(+), 74 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index 31899e6cb0f8..66cf453f4bb7 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -214,9 +214,8 @@ iomap_read_end_io(struct bio *bio) > struct iomap_readpage_ctx { > struct page *cur_page; > bool cur_page_in_bio; > - bool is_readahead; > struct bio *bio; > - struct list_head *pages; > + struct readahead_control *rac; > }; > > static void > @@ -307,11 +306,11 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > if (ctx->bio) > submit_bio(ctx->bio); > > - if (ctx->is_readahead) /* same as readahead_gfp_mask */ > + if (ctx->rac) /* same as readahead_gfp_mask */ > gfp |= __GFP_NORETRY | __GFP_NOWARN; > ctx->bio = bio_alloc(gfp, min(BIO_MAX_PAGES, nr_vecs)); > ctx->bio->bi_opf = REQ_OP_READ; > - if (ctx->is_readahead) > + if (ctx->rac) > ctx->bio->bi_opf |= REQ_RAHEAD; > ctx->bio->bi_iter.bi_sector = sector; > bio_set_dev(ctx->bio, iomap->bdev); > @@ -367,36 +366,8 @@ iomap_readpage(struct page *page, const struct iomap_ops *ops) > } > EXPORT_SYMBOL_GPL(iomap_readpage); > > -static struct page * > -iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, > - loff_t length, loff_t *done) > -{ > - while (!list_empty(pages)) { > - struct page *page = lru_to_page(pages); > - > - if (page_offset(page) >= (u64)pos + length) > - break; > - > - list_del(&page->lru); > - if (!add_to_page_cache_lru(page, inode->i_mapping, page->index, > - GFP_NOFS)) > - return page; > - > - /* > - * If we already have a page in the page cache at index we are > - * done. Upper layers don't care if it is uptodate after the > - * readpages call itself as every page gets checked again once > - * actually needed. > - */ > - *done += PAGE_SIZE; > - put_page(page); > - } > - > - return NULL; > -} > - > static loff_t > -iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, > +iomap_readahead_actor(struct inode *inode, loff_t pos, loff_t length, > void *data, struct iomap *iomap, struct iomap *srcmap) > { > struct iomap_readpage_ctx *ctx = data; > @@ -404,10 +375,7 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, > > while (done < length) { > if (!ctx->cur_page) { > - ctx->cur_page = iomap_next_page(inode, ctx->pages, > - pos, length, &done); > - if (!ctx->cur_page) > - break; > + ctx->cur_page = readahead_page(ctx->rac); > ctx->cur_page_in_bio = false; > } > ret = iomap_readpage_actor(inode, pos + done, length - done, > @@ -431,44 +399,48 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, > return done; > } > > -int > -iomap_readpages(struct address_space *mapping, struct list_head *pages, > - unsigned nr_pages, const struct iomap_ops *ops) > +/** > + * iomap_readahead - Attempt to read pages from a file. > + * @rac: Describes the pages to be read. > + * @ops: The operations vector for the filesystem. > + * > + * This function is for filesystems to call to implement their readahead > + * address_space operation. > + * > + * Context: The file is pinned by the caller, and the pages to be read are > + * all locked and have an elevated refcount. This function will unlock > + * the pages (once I/O has completed on them, or I/O has been determined to > + * not be necessary). It will also decrease the refcount once the pages > + * have been submitted for I/O. After this point, the page may be removed > + * from the page cache, and should not be referenced. > + */ Isn't the context documentation something that belongs into the aop documentation? I've never really seen the value of duplicating this information in method instances, as it is just bound to be out of date rather sooner than later.