The patch titled
readahead: make mmap_miss an unsigned int
has been added to the -mm tree. Its filename is
readahead-make-mmap_miss-an-unsigned-int.patch
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------------------------------------------------------
Subject: readahead: make mmap_miss an unsigned int
From: Wu Fengguang <fengguang.wu@xxxxxxxxx>
This makes the performance impact of possible mmap_miss wrap around to be
temporary and tolerable: i.e. MMAP_LOTSAMISS=100 extra readarounds.
Otherwise if ever mmap_miss wraps around to negative, it takes INT_MAX
cache misses to bring it back to normal state. During the time mmap
readaround will be _enabled_ for whatever wild random workload. That's
almost permanent performance impact.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Cc: Ying Han <yinghan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/fs.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN include/linux/fs.h~readahead-make-mmap_miss-an-unsigned-int include/linux/fs.h
--- a/include/linux/fs.h~readahead-make-mmap_miss-an-unsigned-int
+++ a/include/linux/fs.h
@@ -824,7 +824,7 @@ struct file_ra_state {
there are only # of pages ahead */
unsigned int ra_pages; /* Maximum readahead window */
- int mmap_miss; /* Cache miss stat for mmap accesses */
+ unsigned int mmap_miss; /* Cache miss stat for mmap accesses */
loff_t prev_pos; /* Cache last read() position */
};
_
Patches currently in -mm which might be from fengguang.wu@xxxxxxxxx are
linux-next.patch
readahead-make-mmap_miss-an-unsigned-int.patch
readahead-move-max_sane_readahead-calls-into-force_page_cache_readahead.patch
readahead-apply-max_sane_readahead-limit-in-ondemand_readahead.patch
readahead-remove-one-unnecessary-radix-tree-lookup.patch
readahead-increase-interleaved-readahead-size.patch
readahead-remove-sync-async-readahead-call-dependency.patch
readahead-clean-up-and-simplify-the-code-for-filemap-page-fault-readahead.patch
readahead-sequential-mmap-readahead.patch
readahead-enforce-full-readahead-size-on-async-mmap-readahead.patch
readahead-record-mmap-read-around-states-in-file_ra_state.patch
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