Commit-ID: 024c9d2faebdad3fb43fe49ad68e91a36190f1e2
Gitweb: https://git.kernel.org/tip/024c9d2faebdad3fb43fe49ad68e91a36190f1e2
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 9 Oct 2017 10:36:53 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 10 Oct 2017 10:14:03 +0200
sched/core: Ensure load_balance() respects the active_mask
While load_balance() masks the source CPUs against active_mask, it had
a hole against the destination CPU. Ensure the destination CPU is also
part of the 'domain-mask & active-mask' set.
Reported-by: Levin, Alexander (Sasha Levin) <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Fixes: 77d1dfda0e79 ("sched/topology, cpuset: Avoid spurious/wrong domain rebuilds")
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ed2ab47..d3f3094 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8043,6 +8043,13 @@ static int should_we_balance(struct lb_env *env)
int cpu, balance_cpu = -1;
/*
+ * Ensure the balancing environment is consistent; can happen
+ * when the softirq triggers 'during' hotplug.
+ */
+ if (!cpumask_test_cpu(env->dst_cpu, env->cpus))
+ return 0;
+
+ /*
* In the newly idle case, we will allow all the cpu's
* to do the newly idle load balance.
*/
--
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