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Commit a3d5c346 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull scheduler fixes from Ingo Molnar:
 "Two smaller fixes - plus a context tracking tracing fix that is a bit
  bigger"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tracing/context-tracking: Add preempt_schedule_context() for tracing
  sched: Fix clear NOHZ_BALANCE_KICK
  sched/x86: Construct all sibling maps if smt
parents 86c76676 29bb9e5a

arch/x86/kernel/smpboot.c

+4 −4
Original line number Diff line number Diff line
@@ -372,15 +372,15 @@ static bool __cpuinit match_mc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) 


void __cpuinit set_cpu_sibling_map(int cpu)

{

	bool has_mc = boot_cpu_data.x86_max_cores > 1;

	bool has_smt = smp_num_siblings > 1;

	bool has_mp = has_smt || boot_cpu_data.x86_max_cores > 1;

	struct cpuinfo_x86 *c = &cpu_data(cpu);

	struct cpuinfo_x86 *o;

	int i;



	cpumask_set_cpu(cpu, cpu_sibling_setup_mask);



	if (!has_smt && !has_mc) {

	if (!has_mp) {

		cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));

		cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));

		cpumask_set_cpu(cpu, cpu_core_mask(cpu));
@@ -394,7 +394,7 @@ void __cpuinit set_cpu_sibling_map(int cpu) 
		if ((i == cpu) || (has_smt && match_smt(c, o)))

			link_mask(sibling, cpu, i);



		if ((i == cpu) || (has_mc && match_llc(c, o)))

		if ((i == cpu) || (has_mp && match_llc(c, o)))

			link_mask(llc_shared, cpu, i);



	}
@@ -406,7 +406,7 @@ void __cpuinit set_cpu_sibling_map(int cpu) 
	for_each_cpu(i, cpu_sibling_setup_mask) {

		o = &cpu_data(i);



		if ((i == cpu) || (has_mc && match_mc(c, o))) {

		if ((i == cpu) || (has_mp && match_mc(c, o))) {

			link_mask(core, cpu, i);



			/*

include/linux/preempt.h

+17 −1
Original line number Diff line number Diff line
@@ -33,9 +33,25 @@ do { \ 
		preempt_schedule(); \

} while (0)



#ifdef CONFIG_CONTEXT_TRACKING



void preempt_schedule_context(void);



#define preempt_check_resched_context() \

do { \

	if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \

		preempt_schedule_context(); \

} while (0)

#else



#define preempt_check_resched_context() preempt_check_resched()



#endif /* CONFIG_CONTEXT_TRACKING */



#else /* !CONFIG_PREEMPT */



#define preempt_check_resched()		do { } while (0)

#define preempt_check_resched_context()	do { } while (0)



#endif /* CONFIG_PREEMPT */
@@ -88,7 +104,7 @@ do { \ 
do { \

	preempt_enable_no_resched_notrace(); \

	barrier(); \

	preempt_check_resched(); \

	preempt_check_resched_context(); \

} while (0)



#else /* !CONFIG_PREEMPT_COUNT */

kernel/context_tracking.c

+40 −0
Original line number Diff line number Diff line
@@ -70,6 +70,46 @@ void user_enter(void) 
	local_irq_restore(flags);

}



#ifdef CONFIG_PREEMPT

/**

 * preempt_schedule_context - preempt_schedule called by tracing

 *

 * The tracing infrastructure uses preempt_enable_notrace to prevent

 * recursion and tracing preempt enabling caused by the tracing

 * infrastructure itself. But as tracing can happen in areas coming

 * from userspace or just about to enter userspace, a preempt enable

 * can occur before user_exit() is called. This will cause the scheduler

 * to be called when the system is still in usermode.

 *

 * To prevent this, the preempt_enable_notrace will use this function

 * instead of preempt_schedule() to exit user context if needed before

 * calling the scheduler.

 */

void __sched notrace preempt_schedule_context(void)

{

	struct thread_info *ti = current_thread_info();

	enum ctx_state prev_ctx;



	if (likely(ti->preempt_count || irqs_disabled()))

		return;



	/*

	 * Need to disable preemption in case user_exit() is traced

	 * and the tracer calls preempt_enable_notrace() causing

	 * an infinite recursion.

	 */

	preempt_disable_notrace();

	prev_ctx = exception_enter();

	preempt_enable_no_resched_notrace();



	preempt_schedule();



	preempt_disable_notrace();

	exception_exit(prev_ctx);

	preempt_enable_notrace();

}

EXPORT_SYMBOL_GPL(preempt_schedule_context);

#endif /* CONFIG_PREEMPT */



/**

 * user_exit - Inform the context tracking that the CPU is

kernel/sched/core.c

+17 −4
Original line number Diff line number Diff line
@@ -633,7 +633,19 @@ void wake_up_nohz_cpu(int cpu) 
static inline bool got_nohz_idle_kick(void)

{

	int cpu = smp_processor_id();

	return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));



	if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)))

		return false;



	if (idle_cpu(cpu) && !need_resched())

		return true;



	/*

	 * We can't run Idle Load Balance on this CPU for this time so we

	 * cancel it and clear NOHZ_BALANCE_KICK

	 */

	clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));

	return false;

}



#else /* CONFIG_NO_HZ_COMMON */
@@ -1393,8 +1405,9 @@ static void sched_ttwu_pending(void) 


void scheduler_ipi(void)

{

	if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()

	    && !tick_nohz_full_cpu(smp_processor_id()))

	if (llist_empty(&this_rq()->wake_list)

			&& !tick_nohz_full_cpu(smp_processor_id())

			&& !got_nohz_idle_kick())

		return;



	/*
@@ -1417,7 +1430,7 @@ void scheduler_ipi(void) 
	/*

	 * Check if someone kicked us for doing the nohz idle load balance.

	 */

	if (unlikely(got_nohz_idle_kick() && !need_resched())) {

	if (unlikely(got_nohz_idle_kick())) {

		this_rq()->idle_balance = 1;

		raise_softirq_irqoff(SCHED_SOFTIRQ);

	}