Commit-ID:  359aef5a0f04cf4bb62ae9e85a09b1b3608577ce
Gitweb:     http://git.kernel.org/tip/359aef5a0f04cf4bb62ae9e85a09b1b3608577ce
Author:     Thomas Gleixner <[email protected]>
AuthorDate: Thu, 10 Mar 2016 12:54:17 +0100
Committer:  Thomas Gleixner <[email protected]>
CommitDate: Thu, 5 May 2016 13:17:54 +0200

sched/migration: Move CPU_ONLINE into scheduler state

The alleged requirement that the migration notifier has a lower priority than
perf is completely undocumented and there is no indication at all that this is
true. perf does not even handle the CPU_ONLINE notification and perf really
has nothing to do with migration.

Move the CPU_ONLINE code into the sched_activate_cpu() state callback.

Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

---
 kernel/sched/core.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 688e8a8..8d8d903 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5424,17 +5424,6 @@ migration_call(struct notifier_block *nfb, unsigned long 
action, void *hcpu)
 
        switch (action & ~CPU_TASKS_FROZEN) {
 
-       case CPU_ONLINE:
-               /* Update our root-domain */
-               raw_spin_lock_irqsave(&rq->lock, flags);
-               if (rq->rd) {
-                       BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
-
-                       set_rq_online(rq);
-               }
-               raw_spin_unlock_irqrestore(&rq->lock, flags);
-               break;
-
 #ifdef CONFIG_HOTPLUG_CPU
        case CPU_DYING:
                sched_ttwu_pending();
@@ -7090,12 +7079,34 @@ static int cpuset_cpu_inactive(unsigned int cpu)
 
 int sched_cpu_activate(unsigned int cpu)
 {
+       struct rq *rq = cpu_rq(cpu);
+       unsigned long flags;
+
        set_cpu_active(cpu, true);
 
        if (sched_smp_initialized) {
                sched_domains_numa_masks_set(cpu);
                cpuset_cpu_active();
        }
+
+       /*
+        * Put the rq online, if not already. This happens:
+        *
+        * 1) In the early boot process, because we build the real domains
+        *    after all cpus have been brought up.
+        *
+        * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
+        *    domains.
+        */
+       raw_spin_lock_irqsave(&rq->lock, flags);
+       if (rq->rd) {
+               BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+               set_rq_online(rq);
+       }
+       raw_spin_unlock_irqrestore(&rq->lock, flags);
+
+       update_max_interval();
+
        return 0;
 }
 

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