1 Subject: Explain conditional decrement of aff_sched_count
2 From: Andre Detsch <adetsch@br.ibm.com>
3 References: 447133 - LTC50070
5 This patch adds a comment to clarify why atomic_dec_if_positive is being used
6 to decrement gang's aff_sched_count on SPU context unbind.
8 Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
9 Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
10 Signed-off-by: Olaf Hering <olh@suse.de>
12 arch/powerpc/platforms/cell/spufs/sched.c | 5 +++++
13 1 file changed, 5 insertions(+)
15 --- a/arch/powerpc/platforms/cell/spufs/sched.c
16 +++ b/arch/powerpc/platforms/cell/spufs/sched.c
17 @@ -444,6 +444,11 @@ static void spu_unbind_context(struct sp
18 atomic_dec(&cbe_spu_info[spu->node].reserved_spus);
22 + * If ctx->gang->aff_sched_count is positive, SPU affinity is
23 + * being considered in this gang. Using atomic_dec_if_positive
24 + * allow us to skip an explicit check for affinity in this gang
26 atomic_dec_if_positive(&ctx->gang->aff_sched_count);
28 spu_switch_notify(spu, NULL);