xen: credit2: fix 2 (minor) issues in load tracking logic

All calculations that involve load_last_update uses quantities
shifted by LOADAVG_GRANULARITY_SHIFT, so make sure that this
is true even when the field is assigned a value for the first
time, during vcpu allocation.

Also, during migration, while the loads of both the source and
destination runqueues certainly need changing, the vcpu being
moved does not change its running/non-running status, and its
calculated load should hence not be affected.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>

diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index dee961b9e5915750ed15afcd695ff37e6ee93e05..f3b62acfca7c5ff384c27130b0a6472cfa983250 100644 (file)
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -867,7 +867,7 @@ csched2_alloc_vdata(const struct scheduler *ops, struct vcpu *vc, void *dd)
         svc->weight = svc->sdom->weight;
         /* Starting load of 50% */
         svc->avgload = 1ULL << (CSCHED2_PRIV(ops)->load_window_shift - 1);
-        svc->load_last_update = NOW();
+        svc->load_last_update = NOW() >> LOADAVG_GRANULARITY_SHIFT;
     }
     else
     {
@@ -1301,7 +1301,7 @@ static void migrate(const struct scheduler *ops,
         if ( __vcpu_on_runq(svc) )
         {
             __runq_remove(svc);
-            update_load(ops, svc->rqd, svc, -1, now);
+            update_load(ops, svc->rqd, NULL, -1, now);
             on_runq=1;
         }
         __runq_deassign(svc);
@@ -1314,7 +1314,7 @@ static void migrate(const struct scheduler *ops,
         __runq_assign(svc, trqd);
         if ( on_runq )
         {
-            update_load(ops, svc->rqd, svc, 1, now);
+            update_load(ops, svc->rqd, NULL, 1, now);
             runq_insert(ops, svc->vcpu->processor, svc);
             runq_tickle(ops, svc->vcpu->processor, svc, now);
             SCHED_STAT_CRANK(migrate_on_runq);