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| author |  Andre Detsch <adetsch@br.ibm.com>
| 2008-10-21 11:16:09 +1100 |
|---|---|---|
| committer |  Jeremy Kerr <jk@ozlabs.org>
| 2008-10-21 11:16:09 +1100 |
| commit | 34318c253b861f82bd4a2956e6c8ae8ee2c3aae7 (patch) | |
| tree | acf2a66a3d569de53a432e452f278b4ebb9b0def /arch/powerpc | |
| parent | powerpc/spufs: Improve search of node for contexts with SPU affinity (diff) | |
| download | linux-34318c253b861f82bd4a2956e6c8ae8ee2c3aae7.tar.gz linux-34318c253b861f82bd4a2956e6c8ae8ee2c3aae7.tar.bz2 linux-34318c253b861f82bd4a2956e6c8ae8ee2c3aae7.zip | |
powerpc/spufs: Explain conditional decrement of aff_sched_count
This patch adds a comment to clarify why atomic_dec_if_positive is being used
to decrement gang's aff_sched_count on SPU context unbind.
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/platforms/cell/spufs/sched.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c index 6253df5a436e..2ad914c47493 100644 --- a/arch/powerpc/platforms/cell/spufs/sched.c +++ b/arch/powerpc/platforms/cell/spufs/sched.c @@ -444,6 +444,11 @@ static void spu_unbind_context(struct spu *spu, struct spu_context *ctx) atomic_dec(&cbe_spu_info[spu->node].reserved_spus); if (ctx->gang) + /* + * If ctx->gang->aff_sched_count is positive, SPU affinity is + * being considered in this gang. Using atomic_dec_if_positive + * allow us to skip an explicit check for affinity in this gang + */ atomic_dec_if_positive(&ctx->gang->aff_sched_count); spu_switch_notify(spu, NULL); |