GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-21 06:01:23 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

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

Browse source 
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
This commit is contained in:
Linus Torvalds 2013-06-20 08:18:35 -10:00
commit a3d5c3460a
4 changed files with 78 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

40
kernel/context_tracking.c
View file

@ -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