src/patches/suse-2.6.27.31/patches.suse/unmap_vmas-lat

   1 From: andrea@suse.de
   2 Subject: low-latency stuff
   3
   4
   5 My point is that preempt and no-preempt should do the same thing there,
   6 otherwise when you benchmark -preempt, you'll get better latency,
   7 but not because of the preempt feature, but just because of unrelated
   8 latency improvements that have nothing to do with preempt.
   9
  10
  11 ---
  12  mm/memory.c |    8 ++++----
  13  1 file changed, 4 insertions(+), 4 deletions(-)
  14
  15 --- a/mm/memory.c
  16 +++ b/mm/memory.c
  17 @@ -855,11 +855,11 @@ static unsigned long unmap_page_range(st
  18         return addr;
  19  }
  20
  21 -#ifdef CONFIG_PREEMPT
  22 -# define ZAP_BLOCK_SIZE        (8 * PAGE_SIZE)
  23 +#ifdef CONFIG_SMP
  24 +/* zap one pte page at a time */
  25 +#define ZAP_BLOCK_SIZE         (FREE_PTE_NR * PAGE_SIZE)
  26  #else
  27 -/* No preempt: go for improved straight-line efficiency */
  28 -# define ZAP_BLOCK_SIZE        (1024 * PAGE_SIZE)
  29 +#define ZAP_BLOCK_SIZE         (253 * PAGE_SIZE)
  30  #endif
  31
  32  /**