powerpc/spufs: Improve search of node for contexts with SPU affinity

This patch improves redability of the code responsible for trying to find
a node with enough SPUs not committed to other affinity gangs.

An additional check is also added, to avoid taking into account gangs that
have no SPU affinity.

Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
This commit is contained in:
Andre Detsch 2008-10-21 11:15:23 +11:00 committed by Jeremy Kerr
parent 837ef884b7
commit 10baa26c8c

View file

@ -312,6 +312,15 @@ static struct spu *aff_ref_location(struct spu_context *ctx, int mem_aff,
*/
node = cpu_to_node(raw_smp_processor_id());
for (n = 0; n < MAX_NUMNODES; n++, node++) {
/*
* "available_spus" counts how many spus are not potentially
* going to be used by other affinity gangs whose reference
* context is already in place. Although this code seeks to
* avoid having affinity gangs with a summed amount of
* contexts bigger than the amount of spus in the node,
* this may happen sporadically. In this case, available_spus
* becomes negative, which is harmless.
*/
int available_spus;
node = (node < MAX_NUMNODES) ? node : 0;
@ -321,12 +330,10 @@ static struct spu *aff_ref_location(struct spu_context *ctx, int mem_aff,
available_spus = 0;
mutex_lock(&cbe_spu_info[node].list_mutex);
list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
if (spu->ctx && spu->ctx->gang
&& spu->ctx->aff_offset == 0)
available_spus -=
(spu->ctx->gang->contexts - 1);
else
available_spus++;
if (spu->ctx && spu->ctx->gang && !spu->ctx->aff_offset
&& spu->ctx->gang->aff_ref_spu)
available_spus -= spu->ctx->gang->contexts;
available_spus++;
}
if (available_spus < ctx->gang->contexts) {
mutex_unlock(&cbe_spu_info[node].list_mutex);