提交 a3d5c346 编写于 作者: L Linus Torvalds

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
......@@ -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);
/*
......
......@@ -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 */
......
......@@ -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
......
......@@ -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);
}
......
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