lkml.org 
[lkml]   [2011]   [Apr]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH 2/3] readahead: reduce unnecessary mmap_miss increases
    From: Andi Kleen <ak@linux.intel.com>

    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@intel.com>
    Signed-off-by: Andi Kleen <ak@linux.intel.com>
    Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
    ---
    mm/filemap.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    --- linux-next.orig/mm/filemap.c 2011-04-23 09:01:44.000000000 +0800
    +++ linux-next/mm/filemap.c 2011-04-23 09:17:21.000000000 +0800
    @@ -1538,7 +1538,8 @@ 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++;

    /*



    \
     
     \ /
      Last update: 2011-04-26 11:53    [W:0.022 / U:0.220 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site