lkml.org 
[lkml]   [2010]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 14/15] readahead: reduce MMAP_LOTSAMISS for mmap read-around
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



\
 
 \ /
  Last update: 2010-02-24 04:17    [from the cache]
©2003-2011 Jasper Spaans. Advertise on this site