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@xxxxxxx> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx> --- 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>