From patchwork Mon Feb 17 18:45:55 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: 11387199 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 1D09A109A for ; Mon, 17 Feb 2020 18:46:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E886C208C4 for ; Mon, 17 Feb 2020 18:46:20 +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="i7Z6Vj6w" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729842AbgBQSqU (ORCPT ); Mon, 17 Feb 2020 13:46:20 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:48050 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729786AbgBQSqT (ORCPT ); Mon, 17 Feb 2020 13:46:19 -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=IdbzKhHNnhdRYLMVi5hhCdd4h8STLZkROVG6Wr3MY44=; b=i7Z6Vj6wwMTAXfgAvdOo2oaMcJ LqeO+lH8TMReny2uW/bz8R7NrjhQMCZqQlovCEjnNTyLqmMQ5II9orC/y2cXO351y/6QfP/eq9SB7 k7mGlh68xoLUqmuu8w09NYV1CHY3kMnxzhv2y3IWUOcCOiJsjCUWC9k9AcpXUh7eaaZCOITgKAxhR fZWUrVojffqwx2VYvkTw7fzwNCMrwSbu+UDrYys3swceDTofPrN0MSqQpsrYBfX0GbYZ6A7yN84L7 2bd1u1HT7USizpCacyRpB+T6OYW99+W+nD6XoejPSt6ZG1DWxn7U2iCE3DFon9qF4AlFPOq8lsKzk R9ByIgAQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j3lPL-0005AD-Pu; 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 09/16] btrfs: Convert from readpages to readahead Date: Mon, 17 Feb 2020 10:45:55 -0800 Message-Id: <20200217184613.19668-15-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-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: "Matthew Wilcox (Oracle)" Use the new readahead operation in btrfs. Add a readahead_for_each_batch() iterator to optimise the loop in the XArray. Signed-off-by: Matthew Wilcox (Oracle) --- fs/btrfs/extent_io.c | 48 ++++++++++++++--------------------------- fs/btrfs/extent_io.h | 3 +-- fs/btrfs/inode.c | 16 ++++++-------- include/linux/pagemap.h | 27 +++++++++++++++++++++++ 4 files changed, 51 insertions(+), 43 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index c0f202741e09..d9f66058e0a7 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -4278,52 +4278,36 @@ int extent_writepages(struct address_space *mapping, return ret; } -int extent_readpages(struct address_space *mapping, struct list_head *pages, - unsigned nr_pages) +void extent_readahead(struct readahead_control *rac) { struct bio *bio = NULL; unsigned long bio_flags = 0; struct page *pagepool[16]; struct extent_map *em_cached = NULL; - struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree; - int nr = 0; + struct extent_io_tree *tree = &BTRFS_I(rac->mapping->host)->io_tree; u64 prev_em_start = (u64)-1; + int nr; - while (!list_empty(pages)) { - u64 contig_end = 0; - - for (nr = 0; nr < ARRAY_SIZE(pagepool) && !list_empty(pages);) { - struct page *page = lru_to_page(pages); - - prefetchw(&page->flags); - list_del(&page->lru); - if (add_to_page_cache_lru(page, mapping, page->index, - readahead_gfp_mask(mapping))) { - put_page(page); - break; - } - - pagepool[nr++] = page; - contig_end = page_offset(page) + PAGE_SIZE - 1; - } - - if (nr) { - u64 contig_start = page_offset(pagepool[0]); + readahead_for_each_batch(rac, pagepool, ARRAY_SIZE(pagepool), nr) { + u64 contig_start = page_offset(pagepool[0]); + u64 contig_end = page_offset(pagepool[nr - 1]) + PAGE_SIZE - 1; - ASSERT(contig_start + nr * PAGE_SIZE - 1 == contig_end); + ASSERT(contig_start + nr * PAGE_SIZE - 1 == contig_end); - contiguous_readpages(tree, pagepool, nr, contig_start, - contig_end, &em_cached, &bio, &bio_flags, - &prev_em_start); - } + contiguous_readpages(tree, pagepool, nr, contig_start, + contig_end, &em_cached, &bio, &bio_flags, + &prev_em_start); } if (em_cached) free_extent_map(em_cached); - if (bio) - return submit_one_bio(bio, 0, bio_flags); - return 0; + if (bio) { + int ret = submit_one_bio(bio, 0, bio_flags); + if (ret < 0) { + /* XXX: unlock the pages here? */ + } + } } /* diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index 5d205bbaafdc..bddac32948c7 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -198,8 +198,7 @@ int extent_writepages(struct address_space *mapping, struct writeback_control *wbc); int btree_write_cache_pages(struct address_space *mapping, struct writeback_control *wbc); -int extent_readpages(struct address_space *mapping, struct list_head *pages, - unsigned nr_pages); +void extent_readahead(struct readahead_control *rac); int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, __u64 start, __u64 len); void set_page_extent_mapped(struct page *page); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 5b3ec93ff911..d964b2a78ed8 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4794,8 +4794,8 @@ static void evict_inode_truncate_pages(struct inode *inode) /* * Keep looping until we have no more ranges in the io tree. - * We can have ongoing bios started by readpages (called from readahead) - * that have their endio callback (extent_io.c:end_bio_extent_readpage) + * We can have ongoing bios started by readahead that have + * their endio callback (extent_io.c:end_bio_extent_readpage) * still in progress (unlocked the pages in the bio but did not yet * unlocked the ranges in the io tree). Therefore this means some * ranges can still be locked and eviction started because before @@ -6996,11 +6996,11 @@ static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend, * for it to complete) and then invalidate the pages for * this range (through invalidate_inode_pages2_range()), * but that can lead us to a deadlock with a concurrent - * call to readpages() (a buffered read or a defrag call + * call to readahead (a buffered read or a defrag call * triggered a readahead) on a page lock due to an * ordered dio extent we created before but did not have * yet a corresponding bio submitted (whence it can not - * complete), which makes readpages() wait for that + * complete), which makes readahead wait for that * ordered extent to complete while holding a lock on * that page. */ @@ -8239,11 +8239,9 @@ static int btrfs_writepages(struct address_space *mapping, return extent_writepages(mapping, wbc); } -static int -btrfs_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void btrfs_readahead(struct readahead_control *rac) { - return extent_readpages(mapping, pages, nr_pages); + extent_readahead(rac); } static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags) @@ -10448,7 +10446,7 @@ static const struct address_space_operations btrfs_aops = { .readpage = btrfs_readpage, .writepage = btrfs_writepage, .writepages = btrfs_writepages, - .readpages = btrfs_readpages, + .readahead = btrfs_readahead, .direct_IO = btrfs_direct_IO, .invalidatepage = btrfs_invalidatepage, .releasepage = btrfs_releasepage, diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 4f36c06d064d..1bbb60a0bf16 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -669,6 +669,33 @@ static inline void readahead_next(struct readahead_control *rac) #define readahead_for_each(rac, page) \ for (; (page = readahead_page(rac)); readahead_next(rac)) +static inline unsigned int readahead_page_batch(struct readahead_control *rac, + struct page **array, unsigned int size) +{ + unsigned int batch = 0; + XA_STATE(xas, &rac->mapping->i_pages, rac->_start); + struct page *page; + + rac->_batch_count = 0; + xas_for_each(&xas, page, rac->_start + rac->_nr_pages - 1) { + VM_BUG_ON_PAGE(!PageLocked(page), page); + VM_BUG_ON_PAGE(PageTail(page), page); + array[batch++] = page; + rac->_batch_count += hpage_nr_pages(page); + if (PageHead(page)) + xas_set(&xas, rac->_start + rac->_batch_count); + + if (batch == size) + break; + } + + return batch; +} + +#define readahead_for_each_batch(rac, array, size, nr) \ + for (; (nr = readahead_page_batch(rac, array, size)); \ + readahead_next(rac)) + /* The byte offset into the file of this readahead block */ static inline loff_t readahead_offset(struct readahead_control *rac) {