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

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Pull NOHZ updates from Ingo Molnar:
 "NOHZ enhancements, by Frederic Weisbecker, which reorganizes/refactors
  the NOHZ 'can the tick be stopped?' infrastructure and related code to
  be data driven, and harmonizes the naming and handling of all the
  various properties"

[ This makes the ugly "fetch_or()" macro that the scheduler used
  internally a new generic helper, and does a bad job at it.

  I'm pulling it, but I've asked Ingo and Frederic to get this
  fixed up ]

* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched-clock: Migrate to use new tick dependency mask model
  posix-cpu-timers: Migrate to use new tick dependency mask model
  sched: Migrate sched to use new tick dependency mask model
  sched: Account rr tasks
  perf: Migrate perf to use new tick dependency mask model
  nohz: Use enum code for tick stop failure tracing message
  nohz: New tick dependency mask
  nohz: Implement wide kick on top of irq work
  atomic: Export fetch_or()
This commit is contained in:
Linus Torvalds
2016-03-14 19:44:38 -07:00
parent d4e796152a 1f25184656
commit e23604edac
14 changed files with 424 additions and 161 deletions
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49
kernel/sched/core.c
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@@ -320,20 +320,6 @@ static inline void init_hrtick(void)
}
#endif /* CONFIG_SCHED_HRTICK */
/*
* cmpxchg based fetch_or, macro so it works for different integer types
*/
#define fetch_or(ptr, val) \
({ typeof(*(ptr)) __old, __val = *(ptr); \
for (;;) { \
__old = cmpxchg((ptr), __val, __val | (val)); \
if (__old == __val) \
break; \
__val = __old; \
} \
__old; \
})
#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
/*
* Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
@@ -582,31 +568,36 @@ static inline bool got_nohz_idle_kick(void)
#endif /* CONFIG_NO_HZ_COMMON */
#ifdef CONFIG_NO_HZ_FULL
bool sched_can_stop_tick(void)
bool sched_can_stop_tick(struct rq *rq)
{
int fifo_nr_running;
/* Deadline tasks, even if single, need the tick */
if (rq->dl.dl_nr_running)
return false;
/*
* FIFO realtime policy runs the highest priority task. Other runnable
* tasks are of a lower priority. The scheduler tick does nothing.
* FIFO realtime policy runs the highest priority task (after DEADLINE).
* Other runnable tasks are of a lower priority. The scheduler tick
* isn't needed.
*/
if (current->policy == SCHED_FIFO)
fifo_nr_running = rq->rt.rt_nr_running - rq->rt.rr_nr_running;
if (fifo_nr_running)
return true;
/*
* Round-robin realtime tasks time slice with other tasks at the same
* realtime priority. Is this task the only one at this priority?
* realtime priority.
*/
if (current->policy == SCHED_RR) {
struct sched_rt_entity *rt_se = &current->rt;
return list_is_singular(&rt_se->run_list);
if (rq->rt.rr_nr_running) {
if (rq->rt.rr_nr_running == 1)
return true;
else
return false;
}
/*
* More than one running task need preemption.
* nr_running update is assumed to be visible
* after IPI is sent from wakers.
*/
if (this_rq()->nr_running > 1)
/* Normal multitasking need periodic preemption checks */
if (rq->cfs.nr_running > 1)
return false;
return true;