Commit-ID: 22a802907a4bc8aca61c46428a29dcf568456aac
Gitweb: http://git.kernel.org/tip/22a802907a4bc8aca61c46428a29dcf568456aac
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 10 Mar 2016 12:54:10 +0100
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 5 May 2016 13:17:52 +0200
sched: Allow hotplug notifiers to be setup early
Prevent the SMP scheduler related notifiers to be executed before the smp
scheduler is initialized and install them early.
This is a preparatory change for further consolidation of the hotplug notifier
maze.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: rt@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/sched/core.c | 59 ++++++++++++++++++++++++++++++++---------------------
1 file changed, 36 insertions(+), 23 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4df9aaa..328502c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5195,6 +5195,8 @@ out:
#ifdef CONFIG_SMP
+static bool sched_smp_initialized __read_mostly;
+
#ifdef CONFIG_NUMA_BALANCING
/* Migrate current task p to target_cpu */
int migrate_task_to(struct task_struct *p, int target_cpu)
@@ -5513,25 +5515,6 @@ int sched_cpu_starting(unsigned int cpu)
return 0;
}
-static int __init migration_init(void)
-{
- void *cpu = (void *)(long)smp_processor_id();
- int err;
-
- /* Initialize migration for the boot CPU */
- err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
- BUG_ON(err == NOTIFY_BAD);
- migration_call(&migration_notifier, CPU_ONLINE, cpu);
- register_cpu_notifier(&migration_notifier);
-
- /* Register cpu active notifiers */
- cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
- cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
-
- return 0;
-}
-early_initcall(migration_init);
-
static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
#ifdef CONFIG_SCHED_DEBUG
@@ -6711,6 +6694,9 @@ static int sched_domains_numa_masks_update(struct notifier_block *nfb,
{
int cpu = (long)hcpu;
+ if (!sched_smp_initialized)
+ return NOTIFY_DONE;
+
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_ONLINE:
sched_domains_numa_masks_set(cpu);
@@ -7129,6 +7115,9 @@ static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */
static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
void *hcpu)
{
+ if (!sched_smp_initialized)
+ return NOTIFY_DONE;
+
switch (action) {
case CPU_ONLINE_FROZEN:
case CPU_DOWN_FAILED_FROZEN:
@@ -7169,6 +7158,9 @@ static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
bool overflow;
int cpus;
+ if (!sched_smp_initialized)
+ return NOTIFY_DONE;
+
switch (action) {
case CPU_DOWN_PREPARE:
rcu_read_lock_sched();
@@ -7216,10 +7208,6 @@ void __init sched_init_smp(void)
cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
mutex_unlock(&sched_domains_mutex);
- hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE);
- hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
- hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
-
init_hrtick();
/* Move init over to a non-isolated CPU */
@@ -7230,7 +7218,32 @@ void __init sched_init_smp(void)
init_sched_rt_class();
init_sched_dl_class();
+ sched_smp_initialized = true;
}
+
+static int __init migration_init(void)
+{
+ void *cpu = (void *)(long)smp_processor_id();
+ int err;
+
+ /* Initialize migration for the boot CPU */
+ err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
+ BUG_ON(err == NOTIFY_BAD);
+ migration_call(&migration_notifier, CPU_ONLINE, cpu);
+ register_cpu_notifier(&migration_notifier);
+
+ /* Register cpu active notifiers */
+ cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
+ cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
+
+ hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE);
+ hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
+ hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
+
+ return 0;
+}
+early_initcall(migration_init);
+
#else
void __init sched_init_smp(void)
{
--
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