genriq: pick only one CPU while overriding the affinity during migration
With commit bfc60d474137 ("genirq: Use irq_set_affinity_locked to change
irq affinity"), affinity listeners receive the notification when the irq
affinity is changed during migration. If there is no online and
un-isolated CPU available from the user specified affinity, the affinity
is overridden with all online and un-isolated CPUs. The same cpumask is
notified to PM QOS affinity listener which applies PM_QOS_CPU_DMA_LATENCY
vote to all those CPUs. As the low level irqchip driver sets affinity to
only one CPU, do the same while overriding the affinity during migration.
Change-Id: I0bcb75dd356658da100fbeeefd33ef8b121f4d6d
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
index dac3724..e072f71 100644
--- a/kernel/irq/cpuhotplug.c
+++ b/kernel/irq/cpuhotplug.c
@@ -40,6 +40,17 @@
cpu_isolated_mask);
if (cpumask_empty(affinity))
affinity = cpu_online_mask;
+ /*
+ * We are overriding the affinity with all online and
+ * un-isolated cpus. irq_set_affinity_locked() call
+ * below notify this mask to PM QOS affinity listener.
+ * That results in applying the CPU_DMA_LATENCY QOS
+ * to all the CPUs specified in the mask. But the low
+ * level irqchip driver sets the affinity of an irq
+ * to only one CPU. So pick only one CPU from the
+ * prepared mask while overriding the user affinity.
+ */
+ affinity = cpumask_of(cpumask_any(affinity));
ret = true;
}