On 9/15/17 6:35 PM, Dario Faggioli wrote:
static unsigned int __read_mostly opt_migrate_resist = 500;
integer_param("sched_credit2_migrate_resist", opt_migrate_resist);
@@ -1453,6 +1459,26 @@ runq_tickle(const struct scheduler *ops, struct
csched2_vcpu *new, s_time_t now)
(unsigned char *)&d);
}
+ /*
+ * Exclusive pinning is when a vcpu has hard-affinity with only one
+ * cpu, and there is no other vcpu that has hard-affinity with that
+ * same cpu. This is infrequent, but if it happens, is for achieving
+ * the most possible determinism, and least possible overhead for
+ * the vcpus in question.
+ *
+ * Try to identify the vast majority of these situations, and deal
+ * with them quickly.
Sorry, if I have missed to review the earlier series on the same subject.
But, I am not completely satisfied with the condition that pinning to a
pcpu is only possible if and only if no other vcpu has hard affinity of
that pcpu.
I think we can do away with this condition and give pinning a priority.
Your thoughts please..
+ */
+ if ( unlikely((new->flags & CSFLAG_pinned) &&
+ cpumask_test_cpu(cpu, &rqd->idle) &&
+ !cpumask_test_cpu(cpu, &rqd->tickled)) )
+ {
+ ASSERT(cpumask_cycle(cpu, new->vcpu->cpu_hard_affinity) == cpu);
+ SCHED_STAT_CRANK(tickled_idle_cpu_excl);
+ ipid = cpu;
+ goto tickle;
+ }
+
for_each_affinity_balance_step( bs )
{
/* Just skip first step, if we don't have a soft affinity */
@@ -2826,6 +2852,19 @@ csched2_dom_cntl(
return rc;
}
+static void
+csched2_aff_cntl(const struct scheduler *ops, struct vcpu *v,
+ const cpumask_t *hard, const cpumask_t *soft)
+{
+ struct csched2_vcpu *svc = csched2_vcpu(v);
+
+ /* Are we becoming exclusively pinned? */
+ if ( cpumask_weight(hard) == 1 )
+ __set_bit(__CSFLAG_pinned, &svc->flags);
+ else
+ __clear_bit(__CSFLAG_pinned, &svc->flags);
+}
+
static int csched2_sys_cntl(const struct scheduler *ops,
struct xen_sysctl_scheduler_op *sc)
Looks fine.
Anshul
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