diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 4e14f5c0c91e6b4d29907ddb748a784ec94f2f0c..c8c20182cb1b5712edce31b6d30c6811fae5a211 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -118,6 +118,8 @@ extern void cpu_hotplug_disable(void); extern void cpu_hotplug_enable(void); void clear_tasks_mm_cpumask(int cpu); int cpu_down(unsigned int cpu); +extern void pin_current_cpu(void); +extern void unpin_current_cpu(void); #else /* CONFIG_HOTPLUG_CPU */ @@ -129,6 +131,9 @@ static inline int cpus_read_trylock(void) { return true; } static inline void lockdep_assert_cpus_held(void) { } static inline void cpu_hotplug_disable(void) { } static inline void cpu_hotplug_enable(void) { } +static inline void pin_current_cpu(void) { } +static inline void unpin_current_cpu(void) { } + #endif /* !CONFIG_HOTPLUG_CPU */ /* Wrappers which go away once all code is converted */ diff --git a/kernel/cpu.c b/kernel/cpu.c index 57745fd313fde844649ab3db56a37d46c6eb22ad..f16c5f2a2e968e07aad6066e90ac92ab18f6090c 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -281,6 +281,21 @@ static int cpu_hotplug_disabled; #ifdef CONFIG_HOTPLUG_CPU +/** + * pin_current_cpu - Prevent the current cpu from being unplugged + */ +void pin_current_cpu(void) +{ + +} + +/** + * unpin_current_cpu - Allow unplug of current cpu + */ +void unpin_current_cpu(void) +{ +} + DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); void cpus_read_lock(void) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f98c238981754e53ee3ae921488abb0cda5f8048..e03e9a435c73c79b798c7c8aeb01ee980a2b7af2 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7505,6 +7505,7 @@ void migrate_disable(void) } preempt_disable(); + pin_current_cpu(); migrate_disable_update_cpus_allowed(p); p->migrate_disable = 1; @@ -7570,13 +7571,16 @@ void migrate_enable(void) arg.task = p; arg.dest_cpu = dest_cpu; + unpin_current_cpu(); preempt_enable(); stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); tlb_migrate_finish(p->mm); + return; } } - preempt_enable(); + unpin_current_cpu(); + preempt_enable(); } EXPORT_SYMBOL(migrate_enable); #endif