On my smp platform which is made of 5 cores in 2 clusters,I have the
nr_busy_cpus field of sched_group_power struct that is not null when the
platform is fully idle. The root cause seems to be:
During the boot sequence, some CPUs reach the idle loop and set their
NOHZ_IDLE flag while waiting for others CPUs to boot. But the nr_busy_cpus
field is initialized later with the assumption that all CPUs are in the busy
state whereas some CPUs have already set their NOHZ_IDLE flag.
We clear the NOHZ_IDLE flag when nr_busy_cpus is initialized in order to
have a coherent configuration.
Signed-off-by: Vincent Guittot <vincent.guit...@linaro.org>
---
kernel/sched/core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index bae620a..77a01c8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5875,6 +5875,7 @@ static void init_sched_groups_power(int cpu, struct
sched_domain *sd)
update_group_power(sd, cpu);
atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight);
+ clear_bit(NOHZ_IDLE, nohz_flags(cpu));
}
int __weak arch_sd_sibling_asym_packing(void)
--
1.7.9.5
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