src/patches/suse-2.6.27.31/patches.suse/SoN-02-mm-setup_per_zone_pages_min.patch

   1 From: Peter Zijlstra <a.p.zijlstra@chello.nl>
   2 Subject: mm: serialize access to min_free_kbytes
   3 Patch-mainline: No
   4 References: FATE#303834
   5
   6 There is a small race between the procfs caller and the memory hotplug caller
   7 of setup_per_zone_pages_min(). Not a big deal, but the next patch will add yet
   8 another caller. Time to close the gap.
   9
  10 Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
  11 Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
  12 Acked-by: Neil Brown <neilb@suse.de>
  13 Acked-by: Suresh Jayaraman <sjayaraman@suse.de>
  14
  15 ---
  16  mm/page_alloc.c |   16 +++++++++++++---
  17  1 file changed, 13 insertions(+), 3 deletions(-)
  18
  19 --- a/mm/page_alloc.c
  20 +++ b/mm/page_alloc.c
  21 @@ -120,6 +120,7 @@ static char * const zone_names[MAX_NR_ZO
  22          "Movable",
  23  };
  24
  25 +static DEFINE_SPINLOCK(min_free_lock);
  26  int min_free_kbytes = 1024;
  27
  28  unsigned long __meminitdata nr_kernel_pages;
  29 @@ -4265,12 +4266,12 @@ static void setup_per_zone_lowmem_reserv
  30  }
  31
  32  /**
  33 - * setup_per_zone_pages_min - called when min_free_kbytes changes.
  34 + * __setup_per_zone_pages_min - called when min_free_kbytes changes.
  35   *
  36   * Ensures that the pages_{min,low,high} values for each zone are set correctly
  37   * with respect to min_free_kbytes.
  38   */
  39 -void setup_per_zone_pages_min(void)
  40 +static void __setup_per_zone_pages_min(void)
  41  {
  42         unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
  43         unsigned long lowmem_pages = 0;
  44 @@ -4325,6 +4326,15 @@ void setup_per_zone_pages_min(void)
  45         calculate_totalreserve_pages();
  46  }
  47
  48 +void setup_per_zone_pages_min(void)
  49 +{
  50 +       unsigned long flags;
  51 +
  52 +       spin_lock_irqsave(&min_free_lock, flags);
  53 +       __setup_per_zone_pages_min();
  54 +       spin_unlock_irqrestore(&min_free_lock, flags);
  55 +}
  56 +
  57  /*
  58   * Initialise min_free_kbytes.
  59   *
  60 @@ -4360,7 +4370,7 @@ static int __init init_per_zone_pages_mi
  61                 min_free_kbytes = 128;
  62         if (min_free_kbytes > 65536)
  63                 min_free_kbytes = 65536;
  64 -       setup_per_zone_pages_min();
  65 +       __setup_per_zone_pages_min();
  66         setup_per_zone_lowmem_reserve();
  67         return 0;
  68  }