src/patches/suse-2.6.27.25/patches.arch/ppc-spufs-09-Improve-search-of-node-for-contexts-w.patch

   1 Subject: Improve search of node for contexts with SPU affinity
   2 From: Andre Detsch <adetsch@br.ibm.com>
   3 References: 447133 - LTC50070
   4
   5 This patch improves redability of the code responsible for trying to find
   6 a node with enough SPUs not committed to other affinity gangs.
   7
   8 An additional check is also added, to avoid taking into account gangs that
   9 have no SPU affinity.
  10
  11 Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
  12 Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
  13 Signed-off-by: Olaf Hering <olh@suse.de>
  14 ---
  15  arch/powerpc/platforms/cell/spufs/sched.c |   19 +++++++++++++------
  16  1 file changed, 13 insertions(+), 6 deletions(-)
  17
  18 --- a/arch/powerpc/platforms/cell/spufs/sched.c
  19 +++ b/arch/powerpc/platforms/cell/spufs/sched.c
  20 @@ -312,6 +312,15 @@ static struct spu *aff_ref_location(stru
  21          */
  22         node = cpu_to_node(raw_smp_processor_id());
  23         for (n = 0; n < MAX_NUMNODES; n++, node++) {
  24 +               /*
  25 +                * "available_spus" counts how many spus are not potentially
  26 +                * going to be used by other affinity gangs whose reference
  27 +                * context is already in place. Although this code seeks to
  28 +                * avoid having affinity gangs with a summed amount of
  29 +                * contexts bigger than the amount of spus in the node,
  30 +                * this may happen sporadically. In this case, available_spus
  31 +                * becomes negative, which is harmless.
  32 +                */
  33                 int available_spus;
  34
  35                 node = (node < MAX_NUMNODES) ? node : 0;
  36 @@ -321,12 +330,10 @@ static struct spu *aff_ref_location(stru
  37                 available_spus = 0;
  38                 mutex_lock(&cbe_spu_info[node].list_mutex);
  39                 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
  40 -                       if (spu->ctx && spu->ctx->gang
  41 -                                       && spu->ctx->aff_offset == 0)
  42 -                               available_spus -=
  43 -                                       (spu->ctx->gang->contexts - 1);
  44 -                       else
  45 -                               available_spus++;
  46 +                       if (spu->ctx && spu->ctx->gang && !spu->ctx->aff_offset
  47 +                                       && spu->ctx->gang->aff_ref_spu)
  48 +                               available_spus -= spu->ctx->gang->contexts;
  49 +                       available_spus++;
  50                 }
  51                 if (available_spus < ctx->gang->contexts) {
  52                         mutex_unlock(&cbe_spu_info[node].list_mutex);