From: Matthew Wilcox <willy@infradead.org> To: Andrew Morton <akpm@linux-foundation.org> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>, 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, John Hubbard <jhubbard@nvidia.com>, William Kucharski <william.kucharski@oracle.com> Subject: [PATCH v11 12/25] mm: Move end_index check out of readahead loop Date: Tue, 14 Apr 2020 08:02:20 -0700 Message-ID: <20200414150233.24495-13-willy@infradead.org> (raw) In-Reply-To: <20200414150233.24495-1-willy@infradead.org> From: "Matthew Wilcox (Oracle)" <willy@infradead.org> By reducing nr_to_read, we can eliminate this check from inside the loop. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> --- mm/readahead.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/readahead.c b/mm/readahead.c index d01531ef9f3c..998fdd23c0b1 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -167,8 +167,6 @@ void __do_page_cache_readahead(struct address_space *mapping, unsigned long lookahead_size) { struct inode *inode = mapping->host; - struct page *page; - unsigned long end_index; /* The last page we want to read */ LIST_HEAD(page_pool); loff_t isize = i_size_read(inode); gfp_t gfp_mask = readahead_gfp_mask(mapping); @@ -178,22 +176,26 @@ void __do_page_cache_readahead(struct address_space *mapping, ._index = index, }; unsigned long i; + pgoff_t end_index; /* The last page we want to read */ if (isize == 0) return; - end_index = ((isize - 1) >> PAGE_SHIFT); + end_index = (isize - 1) >> PAGE_SHIFT; + if (index > end_index) + return; + /* Don't read past the page containing the last byte of the file */ + if (nr_to_read > end_index - index) + nr_to_read = end_index - index + 1; /* * Preallocate as many pages as we will need. */ for (i = 0; i < nr_to_read; i++) { - if (index + i > end_index) - break; + struct page *page = xa_load(&mapping->i_pages, index + i); BUG_ON(index + i != rac._index + rac._nr_pages); - page = xa_load(&mapping->i_pages, index + i); if (page && !xa_is_value(page)) { /* * Page already present? Kick off the current batch of -- 2.25.1
next prev parent reply index Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-14 15:02 [PATCH v11 00/25] Change readahead API Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 01/25] mm: Move readahead prototypes from mm.h Matthew Wilcox 2020-04-15 9:10 ` Johannes Thumshirn 2020-04-14 15:02 ` [PATCH v11 02/25] mm: Return void from various readahead functions Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 03/25] mm: Ignore return value of ->readpages Matthew Wilcox 2020-04-15 9:17 ` Johannes Thumshirn 2020-04-14 15:02 ` [PATCH v11 04/25] mm: Move readahead nr_pages check into read_pages Matthew Wilcox 2020-04-15 9:19 ` Johannes Thumshirn 2020-04-14 15:02 ` [PATCH v11 05/25] mm: Add new readahead_control API Matthew Wilcox 2020-04-15 1:17 ` Andrew Morton 2020-04-15 2:18 ` Matthew Wilcox 2020-04-15 4:56 ` Andrew Morton 2020-04-15 11:22 ` Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 06/25] mm: Use readahead_control to pass arguments Matthew Wilcox 2020-04-15 9:30 ` Johannes Thumshirn 2020-04-14 15:02 ` [PATCH v11 07/25] mm: Rename various 'offset' parameters to 'index' Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 08/25] mm: rename readahead loop variable to 'i' Matthew Wilcox 2020-04-15 9:31 ` Johannes Thumshirn 2020-04-14 15:02 ` [PATCH v11 09/25] mm: Remove 'page_offset' from readahead loop Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 10/25] mm: Put readahead pages in cache earlier Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 11/25] mm: Add readahead address space operation Matthew Wilcox 2020-04-14 15:02 ` Matthew Wilcox [this message] 2020-04-14 15:02 ` [PATCH v11 13/25] mm: Add page_cache_readahead_unbounded Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 14/25] mm: Document why we don't set PageReadahead Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 15/25] mm: Use memalloc_nofs_save in readahead path Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 16/25] fs: Convert mpage_readpages to mpage_readahead Matthew Wilcox 2020-06-16 22:36 ` [Cluster-devel] " Andreas Gruenbacher 2020-06-17 0:32 ` Matthew Wilcox 2020-06-17 0:57 ` Andreas Grünbacher 2020-06-17 2:21 ` Matthew Wilcox 2020-06-18 12:46 ` Andreas Gruenbacher 2020-06-18 15:03 ` Matthew Wilcox 2020-06-18 16:40 ` Andreas Gruenbacher 2020-04-14 15:02 ` [PATCH v11 17/25] btrfs: Convert from readpages to readahead Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 18/25] erofs: Convert uncompressed files " Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 19/25] erofs: Convert compressed " Matthew Wilcox 2020-04-21 5:42 ` Andrew Morton 2020-04-21 7:28 ` Gao Xiang 2020-04-14 15:02 ` [PATCH v11 20/25] ext4: Convert " Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 21/25] ext4: Pass the inode to ext4_mpage_readpages Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 22/25] f2fs: Convert from readpages to readahead Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 23/25] f2fs: Pass the inode to f2fs_mpage_readpages Matthew Wilcox 2020-04-14 15:02 ` [PATCH v11 24/25] fuse: Convert from readpages to readahead Matthew Wilcox 2020-04-20 11:14 ` Miklos Szeredi 2020-04-20 11:43 ` Matthew Wilcox 2020-04-20 11:54 ` Miklos Szeredi 2020-04-14 15:02 ` [PATCH v11 25/25] iomap: " Matthew Wilcox
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