Messages in this thread Patch in this message | | | Date | Wed, 24 Feb 2010 11:10:15 +0800 | From | Wu Fengguang <> | Subject | [PATCH 14/15] readahead: reduce MMAP_LOTSAMISS for mmap read-around |
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Now that we lifts readahead size from 128KB to 512KB, the MMAP_LOTSAMISS shall be shrinked accordingly.
We shrink it a bit more, so that for sparse random access patterns, only 10*512KB or ~5MB memory will be wasted, instead of the previous 100*128KB or ~12MB. The new threshold "10" is still big enough to avoid turning off read-around for typical executable/lib page faults.
CC: Nick Piggin <npiggin@suse.de> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> --- mm/filemap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- linux.orig/mm/filemap.c 2010-02-21 23:56:22.000000000 +0800 +++ linux/mm/filemap.c 2010-02-21 23:56:26.000000000 +0800 @@ -1393,7 +1393,7 @@ static int page_cache_read(struct file * return ret; } -#define MMAP_LOTSAMISS (100) +#define MMAP_LOTSAMISS (10) /* * Synchronous readahead happens when we don't even find
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