diff options
| author | Frederic Weisbecker <fweisbec@gmail.com> | 2013-04-19 16:17:38 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-04-19 16:31:40 +0200 |
| commit | 555347f6c080d2f25265f981c963605b4dd3610d (patch) | |
| tree | 3233ee51677e5098510771791c0be9d115992714 | |
| parent | a85721601ad22ca4931e106dbc5b2cbf1d28bdea (diff) | |
posix_timers: New API to prevent from stopping the tick when timers are running
Bring a new helper that the full dynticks infrastructure can
call in order to know if it can safely stop the tick from
the posix cpu timers subsystem point of view.
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>
| -rw-r--r-- | include/linux/posix-timers.h | 2 | ||||
| -rw-r--r-- | kernel/posix-cpu-timers.c | 41 |
2 files changed, 28 insertions, 15 deletions
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 042058fdb0a..3698d9d0897 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -122,6 +122,8 @@ void run_posix_cpu_timers(struct task_struct *task); void posix_cpu_timers_exit(struct task_struct *task); void posix_cpu_timers_exit_group(struct task_struct *task); +bool posix_cpu_timers_can_stop_tick(struct task_struct *tsk); + void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx, cputime_t *newval, cputime_t *oldval); diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 0bc33561a43..84d5cb372ed 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -155,6 +155,21 @@ static void bump_cpu_timer(struct k_itimer *timer, } } +/** + * task_cputime_zero - Check a task_cputime struct for all zero fields. + * + * @cputime: The struct to compare. + * + * Checks @cputime to see if all fields are zero. Returns true if all fields + * are zero, false if any field is nonzero. + */ +static inline int task_cputime_zero(const struct task_cputime *cputime) +{ + if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime) + return 1; + return 0; +} + static inline cputime_t prof_ticks(struct task_struct *p) { cputime_t utime, stime; @@ -654,6 +669,17 @@ static void posix_cpu_timer_kick_nohz(void) { schedule_work(&nohz_kick_work); } + +bool posix_cpu_timers_can_stop_tick(struct task_struct *tsk) +{ + if (!task_cputime_zero(&tsk->cputime_expires)) + return true; + + if (tsk->signal->cputimer.running) + return true; + + return false; +} #else static inline void posix_cpu_timer_kick_nohz(void) { } #endif @@ -1032,21 +1058,6 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, } } -/** - * task_cputime_zero - Check a task_cputime struct for all zero fields. - * - * @cputime: The struct to compare. - * - * Checks @cputime to see if all fields are zero. Returns true if all fields - * are zero, false if any field is nonzero. - */ -static inline int task_cputime_zero(const struct task_cputime *cputime) -{ - if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime) - return 1; - return 0; -} - /* * Check for any per-thread CPU timers that have fired and move them * off the tsk->*_timers list onto the firing list. Per-thread timers |