Commit 34318c25 authored by Andre Detsch's avatar Andre Detsch Committed by Jeremy Kerr
Browse files

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: default avatarAndre Detsch <adetsch@br.ibm.com>
Signed-off-by: default avatarJeremy Kerr <jk@ozlabs.org>
parent 10baa26c
...@@ -444,6 +444,11 @@ static void spu_unbind_context(struct spu *spu, struct spu_context *ctx) ...@@ -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); atomic_dec(&cbe_spu_info[spu->node].reserved_spus);
if (ctx->gang) 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); atomic_dec_if_positive(&ctx->gang->aff_sched_count);
spu_switch_notify(spu, NULL); spu_switch_notify(spu, NULL);
......
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