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authorMatthew Wilcox (Oracle) <willy@infradead.org>2020-06-02 07:46:47 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-02 20:59:06 +0300
commitb0f31d78cbc191058e654c8eb062a864b6c9a7eb (patch)
tree6c692ab6616a70c8c07edc0e03f21bbdc85c2336 /mm/readahead.c
parent8151b4c8bee43cea7a28cb0300123df90880e60c (diff)
downloadlinux-b0f31d78cbc191058e654c8eb062a864b6c9a7eb.tar.xz
mm: move end_index check out of readahead loop
By reducing nr_to_read, we can eliminate this check from inside the loop. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Cc: Chao Yu <yuchao0@huawei.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Dave Chinner <dchinner@redhat.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Gao Xiang <gaoxiang25@huawei.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Link: http://lkml.kernel.org/r/20200414150233.24495-13-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/readahead.c')
-rw-r--r--mm/readahead.c14
1 files 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