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posix_timers: Kick full dynticks CPUs when a posix cpu timer is armed

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Kick the full dynticks CPUs when a posix cpu timer is enqueued by
way of a standard call to posix_cpu_timer_set() or set_process_cpu_timer().
This also include rescheduled firing timers.

This way they can re-evaluate the state of (and possibly restart) their
tick against the new expiry modification.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Frederic Weisbecker 2013-04-18 01:31:13 +02:00
parent 76c24fb054
commit a85721601a
1 changed files with 34 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

35
kernel/posix-cpu-timers.c
View file

@ -10,6 +10,8 @@
#include <linux/kernel_stat.h>
#include <trace/events/timer.h>
#include <linux/random.h>
#include <linux/tick.h>
#include <linux/workqueue.h>
/*
* Called after updating RLIMIT_CPU to run cpu timer and update
@ -636,6 +638,26 @@ static int cpu_timer_sample_group(const clockid_t which_clock,
return 0;
}
#ifdef CONFIG_NO_HZ_FULL
static void nohz_kick_work_fn(struct work_struct *work)
{
tick_nohz_full_kick_all();
}
static DECLARE_WORK(nohz_kick_work, nohz_kick_work_fn);
/*
* We need the IPIs to be sent from sane process context.
* The posix cpu timers are always set with irqs disabled.
*/
static void posix_cpu_timer_kick_nohz(void)
{
schedule_work(&nohz_kick_work);
}
#else
static inline void posix_cpu_timer_kick_nohz(void) { }
#endif
/*
* Guts of sys_timer_settime for CPU timers.
* This is called with the timer locked and interrupts disabled.
@ -794,6 +816,8 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
sample_to_timespec(timer->it_clock,
old_incr, &old->it_interval);
}
if (!ret)
posix_cpu_timer_kick_nohz();
return ret;
}
@ -1336,6 +1360,13 @@ void run_posix_cpu_timers(struct task_struct *tsk)
cpu_timer_fire(timer);
spin_unlock(&timer->it_lock);
}
/*
* In case some timers were rescheduled after the queue got emptied,
* wake up full dynticks CPUs.
*/
if (tsk->signal->cputimer.running)
posix_cpu_timer_kick_nohz();
}
/*
@ -1366,7 +1397,7 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
}
if (!*newval)
return;
goto out;
*newval += now.cpu;
}
@ -1384,6 +1415,8 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
tsk->signal->cputime_expires.virt_exp = *newval;
break;
}
out:
posix_cpu_timer_kick_nohz();
}
static int do_cpu_nanosleep(const clockid_t which_clock, int flags,