diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2016-03-10 12:54:14 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-05-06 14:58:24 +0200 |
| commit | b2454caa8977ade27292a71f2def5e403e24b4d5 (patch) | |
| tree | aead0505616aa4402a99f4a85bf2dc6d001e2a4a | |
| parent | 40190a78f85fec29f0fdd21f6b4415712085711e (diff) | |
sched/hotplug: Move sync_rcu to be with set_cpu_active(false)
The sync_rcu stuff is specificically for clearing bits in the active
mask, such that everybody will observe the bit cleared and will not
consider the cleared CPU for load-balancing etc.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160310120025.169219710@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | kernel/cpu.c | 15 | ||||
| -rw-r--r-- | kernel/sched/core.c | 14 |
2 files changed, 14 insertions, 15 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 15402b72fbc7..c134a35374a1 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -703,21 +703,6 @@ static int takedown_cpu(unsigned int cpu) struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); int err; - /* - * By now we've cleared cpu_active_mask, wait for all preempt-disabled - * and RCU users of this state to go away such that all new such users - * will observe it. - * - * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might - * not imply sync_sched(), so wait for both. - * - * Do sync before park smpboot threads to take care the rcu boost case. - */ - if (IS_ENABLED(CONFIG_PREEMPT)) - synchronize_rcu_mult(call_rcu, call_rcu_sched); - else - synchronize_rcu(); - /* Park the smpboot threads */ kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); smpboot_park_threads(cpu); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 73bcd937d436..0a3107809972 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7112,6 +7112,20 @@ int sched_cpu_deactivate(unsigned int cpu) int ret; set_cpu_active(cpu, false); + /* + * We've cleared cpu_active_mask, wait for all preempt-disabled and RCU + * users of this state to go away such that all new such users will + * observe it. + * + * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might + * not imply sync_sched(), so wait for both. + * + * Do sync before park smpboot threads to take care the rcu boost case. + */ + if (IS_ENABLED(CONFIG_PREEMPT)) + synchronize_rcu_mult(call_rcu, call_rcu_sched); + else + synchronize_rcu(); if (!sched_smp_initialized) return 0; |