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 way they can re-evaluate the state of (and possibly restart) their
tick against the new expiry modification.
Signed-off-by: Frederic Weisbecker <fweis...@gmail.com>
Cc: Chris Metcalf <cmetc...@tilera.com>
Cc: Christoph Lameter <c...@linux.com>
Cc: Geoff Levand <ge...@infradead.org>
Cc: Gilad Ben Yossef <gi...@benyossef.com>
Cc: Hakan Akkan <hakanak...@gmail.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Kevin Hilman <khil...@linaro.org>
Cc: Li Zhong <zh...@linux.vnet.ibm.com>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortma...@windriver.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Thomas Gleixner <t...@linutronix.de>
---
kernel/posix-cpu-timers.c | 28 +++++++++++++++++++++++++++-
1 files changed, 27 insertions(+), 1 deletions(-)
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 3b73ae8..a9053ad7 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -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;
}
@@ -1369,7 +1393,7 @@ void set_process_cpu_timer(struct task_struct *tsk,
unsigned int clock_idx,
}
if (!*newval)
- return;
+ goto out;
*newval += now.cpu;
}
@@ -1387,6 +1411,8 @@ 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,
--
1.7.5.4
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