[POWERPC] spufs: try to route SPU interrupts to local node

Currently, we re-route SPU interrupts to the current cpu, which may be
on a remote node. In the case of time slicing, all spu interrupts will
end up routed to the same cpu, where the spusched_tick occurs.

This change routes mfc interrupts to the cpu where the controlling
thread last ran, provided that cpu is on the same node as the spu
(otherwise don't reroute interrupts).

This should improve performance and provide a more predictable
environment for processing spu exceptions. In the past we have seen
concurrent delivery of spu exceptions to two cpus. This eliminates that
concern.

Signed-off-by: Luke Browning <lukebr@linux.vnet.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 14 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/cell/spu_priv1_mmio.c b/arch/powerpc/platforms/cell/spu_priv1_mmio.c
index 67fa7247b80a..906a0a2a9fe1 100644
--- a/arch/powerpc/platforms/cell/spu_priv1_mmio.c
+++ b/arch/powerpc/platforms/cell/spu_priv1_mmio.c
@@ -28,6 +28,7 @@
 #include <linux/io.h>
 #include <linux/mutex.h>
 #include <linux/device.h>
+#include <linux/sched.h>
 
 #include <asm/spu.h>
 #include <asm/spu_priv1.h>
@@ -75,8 +76,19 @@ static u64 int_stat_get(struct spu *spu, int class)
 
 static void cpu_affinity_set(struct spu *spu, int cpu)
 {
-	u64 target = iic_get_target_id(cpu);
-	u64 route = target << 48 | target << 32 | target << 16;
+	u64 target;
+	u64 route;
+
+	if (nr_cpus_node(spu->node)) {
+		cpumask_t spumask = node_to_cpumask(spu->node);
+		cpumask_t cpumask = node_to_cpumask(cpu_to_node(cpu));
+
+		if (!cpus_intersects(spumask, cpumask))
+			return;
+	}
+
+	target = iic_get_target_id(cpu);
+	route = target << 48 | target << 32 | target << 16;
 	out_be64(&spu->priv1->int_route_RW, route);
 }