[Xen-devel] [PATCH v2 2/6] xen: ARM: suspend the tick (if in use) when going idle.

[Dario Faggioli <dario.faggioli@xxxxxxxxxx>]

Since commit 964fae8ac ("cpuidle: suspend/resume scheduler
tick timer during cpu idle state entry/exit"), if a scheduler
has a periodic tick timer, we stop it when going idle.

This, however, is only true for x86. Make it true for ARM as
well.

Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
Cc: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/arm/domain.c |   29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index eeebbdb..2160d2b 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -39,6 +39,25 @@
 
 DEFINE_PER_CPU(struct vcpu *, curr_vcpu);
 
+static void do_idle(void)
+{
+    unsigned int cpu = smp_processor_id();
+
+    sched_tick_suspend();
+    /* sched_tick_suspend() can raise TIMER_SOFTIRQ. Process it now. */
+    process_pending_softirqs();
+
+    local_irq_disable();
+    if ( cpu_is_haltable(cpu) )
+    {
+        dsb(sy);
+        wfi();
+    }
+    local_irq_enable();
+
+    sched_tick_resume();
+}
+
 void idle_loop(void)
 {
     unsigned int cpu = smp_processor_id();
@@ -52,15 +71,7 @@ void idle_loop(void)
         if ( unlikely(tasklet_work_to_do(cpu)) )
             do_tasklet();
         else
-        {
-            local_irq_disable();
-            if ( cpu_is_haltable(cpu) )
-            {
-                dsb(sy);
-                wfi();
-            }
-            local_irq_enable();
-        }
+            do_idle();
 
         do_softirq();
         /*


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