[Xen-devel] [PATCH] sched/null: skip vCPUs on the waitqueue that are blocked

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Avoid scheduling vCPUs that are blocked, there's no point in assigning
them to a pCPU because they are not going to run anyway and might
prevent a non-blocked vCPU from actually running.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
Cc: Dario Faggioli <raistlin@xxxxxxxx>
---
 xen/common/sched_null.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xen/common/sched_null.c b/xen/common/sched_null.c
index b4a24baf8e..78a3b12845 100644
--- a/xen/common/sched_null.c
+++ b/xen/common/sched_null.c
@@ -781,6 +781,10 @@ static struct task_slice null_schedule(const struct 
scheduler *ops,
         {
             list_for_each_entry( wvc, &prv->waitq, waitq_elem )
             {
+                if ( test_bit(_VPF_down, &wvc->vcpu->pause_flags) )
+                    /* Skip vCPUs that are down. */
+                    continue;
+
                 if ( bs == BALANCE_SOFT_AFFINITY &&
                      !has_soft_affinity(wvc->vcpu, 
wvc->vcpu->cpu_hard_affinity) )
                     continue;
-- 
2.14.3 (Apple Git-98)


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