From patchwork Tue Feb 11 01:03:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Matthew Wilcox (Oracle)" X-Patchwork-Id: 11374553 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6F2C2109A for ; Tue, 11 Feb 2020 01:04:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 46AF120838 for ; Tue, 11 Feb 2020 01:04:34 +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="DHdtZGeV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727969AbgBKBD6 (ORCPT ); Mon, 10 Feb 2020 20:03:58 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:54790 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727952AbgBKBD5 (ORCPT ); Mon, 10 Feb 2020 20:03:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=aRGXOYJKfqUnemNd2/EE+PIGxC7h8UcYZ50qWybxHys=; b=DHdtZGeV6dx9AasdzgsZ7AwumB y4YbUuEU4MMCmhdea8evj8EzmKtUcN1PIlxQwwzj3aN8cw0vNA33rnii1eZUADbN9wbPoa0k0y5eD UtUIQde61wWRHMGxe6LHa22mOd1OMmHBNEwy2cK/WhwliMvriibB32zqqR5775ETs4XMG+4GqJY1L CCVooOXShnHfaHkr5nHvPkpQ28zCC1M7X89h0rrpVpUFWB54NJVDYmcRI1OFzHeVNneSRwb3bzD3d KvzWnYWxHLM0F8RdiLUeD317FsBldabHSRJyWR/tjOYG3FadyGe6Edfh32NmJ4HswNBMc2eEdICCS m4N+go8g==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j1Jxu-0001nx-Eg; Tue, 11 Feb 2020 01:03:50 +0000 From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , 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: [PATCH v5 05/13] mm: Add page_cache_readahead_limit Date: Mon, 10 Feb 2020 17:03:40 -0800 Message-Id: <20200211010348.6872-6-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200211010348.6872-1-willy@infradead.org> References: <20200211010348.6872-1-willy@infradead.org> MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: "Matthew Wilcox (Oracle)" ext4 and f2fs have duplicated the guts of the readahead code so they can read past i_size. Instead, separate out the guts of the readahead code so they can call it directly. Signed-off-by: Matthew Wilcox (Oracle) --- fs/ext4/verity.c | 35 ++-------------------------- fs/f2fs/verity.c | 35 ++-------------------------- include/linux/pagemap.h | 4 ++++ mm/readahead.c | 51 ++++++++++++++++++++++++----------------- 4 files changed, 38 insertions(+), 87 deletions(-) diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c index dc5ec724d889..f6e0bf05933e 100644 --- a/fs/ext4/verity.c +++ b/fs/ext4/verity.c @@ -342,37 +342,6 @@ static int ext4_get_verity_descriptor(struct inode *inode, void *buf, return desc_size; } -/* - * Prefetch some pages from the file's Merkle tree. - * - * This is basically a stripped-down version of __do_page_cache_readahead() - * which works on pages past i_size. - */ -static void ext4_merkle_tree_readahead(struct address_space *mapping, - pgoff_t start_index, unsigned long count) -{ - LIST_HEAD(pages); - unsigned int nr_pages = 0; - struct page *page; - pgoff_t index; - struct blk_plug plug; - - for (index = start_index; index < start_index + count; index++) { - page = xa_load(&mapping->i_pages, index); - if (!page || xa_is_value(page)) { - page = __page_cache_alloc(readahead_gfp_mask(mapping)); - if (!page) - break; - page->index = index; - list_add(&page->lru, &pages); - nr_pages++; - } - } - blk_start_plug(&plug); - ext4_mpage_readpages(mapping, &pages, NULL, nr_pages, true); - blk_finish_plug(&plug); -} - static struct page *ext4_read_merkle_tree_page(struct inode *inode, pgoff_t index, unsigned long num_ra_pages) @@ -386,8 +355,8 @@ static struct page *ext4_read_merkle_tree_page(struct inode *inode, if (page) put_page(page); else if (num_ra_pages > 1) - ext4_merkle_tree_readahead(inode->i_mapping, index, - num_ra_pages); + page_cache_readahead_limit(inode->i_mapping, NULL, + index, LONG_MAX, num_ra_pages, 0); page = read_mapping_page(inode->i_mapping, index, NULL); } return page; diff --git a/fs/f2fs/verity.c b/fs/f2fs/verity.c index d7d430a6f130..71a3e36721fa 100644 --- a/fs/f2fs/verity.c +++ b/fs/f2fs/verity.c @@ -222,37 +222,6 @@ static int f2fs_get_verity_descriptor(struct inode *inode, void *buf, return size; } -/* - * Prefetch some pages from the file's Merkle tree. - * - * This is basically a stripped-down version of __do_page_cache_readahead() - * which works on pages past i_size. - */ -static void f2fs_merkle_tree_readahead(struct address_space *mapping, - pgoff_t start_index, unsigned long count) -{ - LIST_HEAD(pages); - unsigned int nr_pages = 0; - struct page *page; - pgoff_t index; - struct blk_plug plug; - - for (index = start_index; index < start_index + count; index++) { - page = xa_load(&mapping->i_pages, index); - if (!page || xa_is_value(page)) { - page = __page_cache_alloc(readahead_gfp_mask(mapping)); - if (!page) - break; - page->index = index; - list_add(&page->lru, &pages); - nr_pages++; - } - } - blk_start_plug(&plug); - f2fs_mpage_readpages(mapping, &pages, NULL, nr_pages, true); - blk_finish_plug(&plug); -} - static struct page *f2fs_read_merkle_tree_page(struct inode *inode, pgoff_t index, unsigned long num_ra_pages) @@ -266,8 +235,8 @@ static struct page *f2fs_read_merkle_tree_page(struct inode *inode, if (page) put_page(page); else if (num_ra_pages > 1) - f2fs_merkle_tree_readahead(inode->i_mapping, index, - num_ra_pages); + page_cache_readahead_limit(inode->i_mapping, NULL, + index, LONG_MAX, num_ra_pages, 0); page = read_mapping_page(inode->i_mapping, index, NULL); } return page; diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 13efafaf7e1f..ddb2d1b43212 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -389,6 +389,10 @@ extern struct page * read_cache_page_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp_mask); extern int read_cache_pages(struct address_space *mapping, struct list_head *pages, filler_t *filler, void *data); +unsigned long page_cache_readahead_limit(struct address_space *mapping, + struct file *file, pgoff_t start, pgoff_t end_index, + unsigned long nr_to_read, unsigned long lookahead_size); + static inline struct page *read_mapping_page(struct address_space *mapping, pgoff_t index, void *data) diff --git a/mm/readahead.c b/mm/readahead.c index 933b32e0c90a..29ca25c8f01e 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -144,38 +144,22 @@ static void read_pages(struct readahead_control *rac, struct list_head *pages) blk_finish_plug(&plug); } -/* - * __do_page_cache_readahead() actually reads a chunk of disk. It allocates - * the pages first, then submits them for I/O. This avoids the very bad - * behaviour which would occur if page allocations are causing VM writeback. - * We really don't want to intermingle reads and writes like that. - * - * Returns the number of pages requested, or the maximum amount of I/O allowed. - */ -unsigned long __do_page_cache_readahead(struct address_space *mapping, - struct file *filp, pgoff_t start, unsigned long nr_to_read, - unsigned long lookahead_size) +unsigned long page_cache_readahead_limit(struct address_space *mapping, + struct file *file, pgoff_t start, pgoff_t end_index, + unsigned long nr_to_read, unsigned long lookahead_size) { - struct inode *inode = mapping->host; - unsigned long end_index; /* The last page we want to read */ LIST_HEAD(page_pool); int page_idx; pgoff_t page_offset = start; - loff_t isize = i_size_read(inode); gfp_t gfp_mask = readahead_gfp_mask(mapping); bool use_list = mapping->a_ops->readpages; struct readahead_control rac = { .mapping = mapping, - .file = filp, + .file = file, .start = start, .nr_pages = 0, }; - if (isize == 0) - goto out; - - end_index = ((isize - 1) >> PAGE_SHIFT); - /* * Preallocate as many pages as we will need. */ @@ -233,9 +217,34 @@ unsigned long __do_page_cache_readahead(struct address_space *mapping, */ read_pages(&rac, &page_pool); BUG_ON(!list_empty(&page_pool)); -out: return rac.nr_pages; } +EXPORT_SYMBOL_GPL(page_cache_readahead_limit); + +/* + * __do_page_cache_readahead() actually reads a chunk of disk. It allocates + * the pages first, then submits them for I/O. This avoids the very bad + * behaviour which would occur if page allocations are causing VM writeback. + * We really don't want to intermingle reads and writes like that. + * + * Returns the number of pages requested, or the maximum amount of I/O allowed. + */ +unsigned long __do_page_cache_readahead(struct address_space *mapping, + struct file *file, pgoff_t start, unsigned long nr_to_read, + unsigned long lookahead_size) +{ + struct inode *inode = mapping->host; + unsigned long end_index; /* The last page we want to read */ + loff_t isize = i_size_read(inode); + + if (isize == 0) + return 0; + + end_index = ((isize - 1) >> PAGE_SHIFT); + + return page_cache_readahead_limit(mapping, file, start, end_index, + nr_to_read, lookahead_size); +} /* * Chunk the readahead into 2 megabyte units, so that we don't pin too much