From patchwork Mon Feb 17 18:45:51 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: 1239520 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20170209 header.b=TSzeKvD/; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48LtKQ74Mkz9sSW for ; Tue, 18 Feb 2020 05:48:10 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729610AbgBQSsK (ORCPT ); Mon, 17 Feb 2020 13:48:10 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:48164 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729897AbgBQSqW (ORCPT ); Mon, 17 Feb 2020 13:46:22 -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=sD3WK8blKDBvHqnGFtSLkIMu7MQ1pNDfe0fQpuod3eg=; b=TSzeKvD/R0+qInKvOW0Z9NR8FI SjS8g/W6kCr1vojCeVDmW/rsDXq0PSrJhA6qfv2MrHnY6nSF+eehaMdOwfrABFEiRW7V1DONZjqJ+ eAKWCtyr9tFuYqAwK3SgYhmo6IRTF2A5TeGtpJ8gnGJy/UleL1Y37j4hUsVtF5ZKToHYkrPVJUWZR oj3SE/bSHSbnLvrjHDb20NaQSmBE7u74peXxwIif6wsYrtMD6NAyV8/vOcmNp8IvOX1/11N3wjzXk r8wYKT6vbNZ+ZVJLxjNrrfML3cr/H7us0rQSDgN/ydRJJOQ683Dsp8vzcO66LRDQaRYwDIFaMjsX0 rjXGVJZQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j3lPL-00059T-KR; Mon, 17 Feb 2020 18:46:15 +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 v6 07/16] mm: Add page_cache_readahead_limit Date: Mon, 17 Feb 2020 10:45:51 -0800 Message-Id: <20200217184613.19668-11-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200217184613.19668-1-willy@infradead.org> References: <20200217184613.19668-1-willy@infradead.org> MIME-Version: 1.0 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@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 | 46 +++++++++++++++++++++++++---------------- 4 files changed, 36 insertions(+), 84 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 bd4291f78f41..4f36c06d064d 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); +void page_cache_readahead_limit(struct address_space *mapping, + struct file *file, pgoff_t offset, 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 5be7e1cb8666..566693f4e539 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -142,35 +142,21 @@ 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. - */ -void __do_page_cache_readahead(struct address_space *mapping, - struct file *filp, pgoff_t offset, unsigned long nr_to_read, - unsigned long lookahead_size) +void page_cache_readahead_limit(struct address_space *mapping, + struct file *file, pgoff_t offset, 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; - 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 = offset, ._nr_pages = 0, }; - if (isize == 0) - return; - - end_index = ((isize - 1) >> PAGE_SHIFT); - /* * Preallocate as many pages as we will need. */ @@ -225,6 +211,30 @@ void __do_page_cache_readahead(struct address_space *mapping, read_pages(&rac, &page_pool); BUG_ON(!list_empty(&page_pool)); } +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. + */ +void __do_page_cache_readahead(struct address_space *mapping, + struct file *file, pgoff_t offset, 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; + + end_index = ((isize - 1) >> PAGE_SHIFT); + + page_cache_readahead_limit(mapping, file, offset, end_index, + nr_to_read, lookahead_size); +} /* * Chunk the readahead into 2 megabyte units, so that we don't pin too much