The patch titled
Subject: mm: move end_index check out of readahead loop
has been added to the -mm tree. Its filename is
mm-move-end_index-check-out-of-readahead-loop.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-move-end_index-check-out-of-readahead-loop.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-move-end_index-check-out-of-readahead-loop.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: move end_index check out of readahead loop
By reducing nr_to_read, we can eliminate this check from inside the loop.
Link: http://lkml.kernel.org/r/20200414150233.24495-13-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
Cc: Chao Yu <yuchao0@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Cc: Dave Chinner <dchinner@xxxxxxxxxx>
Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: Gao Xiang <gaoxiang25@xxxxxxxxxx>
Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Cc: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/readahead.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
--- a/mm/readahead.c~mm-move-end_index-check-out-of-readahead-loop
+++ a/mm/readahead.c
@@ -167,8 +167,6 @@ void __do_page_cache_readahead(struct ad
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 ad
._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
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-move-readahead-prototypes-from-mmh.patch
mm-return-void-from-various-readahead-functions.patch
mm-ignore-return-value-of-readpages.patch
mm-move-readahead-nr_pages-check-into-read_pages.patch
mm-add-new-readahead_control-api.patch
mm-use-readahead_control-to-pass-arguments.patch
mm-rename-various-offset-parameters-to-index.patch
mm-rename-readahead-loop-variable-to-i.patch
mm-remove-page_offset-from-readahead-loop.patch
mm-put-readahead-pages-in-cache-earlier.patch
mm-add-readahead-address-space-operation.patch
mm-move-end_index-check-out-of-readahead-loop.patch
mm-add-page_cache_readahead_unbounded.patch
mm-document-why-we-dont-set-pagereadahead.patch
mm-use-memalloc_nofs_save-in-readahead-path.patch
fs-convert-mpage_readpages-to-mpage_readahead.patch
btrfs-convert-from-readpages-to-readahead.patch
erofs-convert-uncompressed-files-from-readpages-to-readahead.patch
erofs-convert-compressed-files-from-readpages-to-readahead.patch
ext4-convert-from-readpages-to-readahead.patch
ext4-pass-the-inode-to-ext4_mpage_readpages.patch
f2fs-convert-from-readpages-to-readahead.patch
f2fs-pass-the-inode-to-f2fs_mpage_readpages.patch
fuse-convert-from-readpages-to-readahead.patch
iomap-convert-from-readpages-to-readahead.patch
