The patch titled
readahead: reduce unnecessary mmap_miss increases
has been added to the -mm tree. Its filename is
readahead-reduce-unnecessary-mmap_miss-increases.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: readahead: reduce unnecessary mmap_miss increases
From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
The original INT_MAX is too large, reduce it to
- avoid unnecessarily dirtying/bouncing the cache line
- restore mmap read-around faster on changed access pattern
Tested-by: Tim Chen <tim.c.chen@xxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/filemap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN mm/filemap.c~readahead-reduce-unnecessary-mmap_miss-increases mm/filemap.c
--- a/mm/filemap.c~readahead-reduce-unnecessary-mmap_miss-increases
+++ a/mm/filemap.c
@@ -1577,7 +1577,8 @@ static void do_sync_mmap_readahead(struc
return;
}
- if (ra->mmap_miss < INT_MAX)
+ /* Avoid banging the cache line if not needed */
+ if (ra->mmap_miss < MMAP_LOTSAMISS * 10)
ra->mmap_miss++;
/*
_
Patches currently in -mm which might be from ak@xxxxxxxxxxxxxxx are
origin.patch
linux-next.patch
mm-rename-alloc_pages_exact.patch
mm-make-new-alloc_pages_exact.patch
mm-reuse-__free_pages_exact-in-__alloc_pages_exact.patch
readahead-return-early-when-readahead-is-disabled.patch
readahead-reduce-unnecessary-mmap_miss-increases.patch
readahead-trigger-mmap-sequential-readahead-on-pg_readahead.patch
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