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authorFrederic Weisbecker <fweisbec@gmail.com>2012-10-11 17:52:56 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2012-11-17 19:30:18 +0100
commit33a5f6261a61af28f7b4c86f9f958da0f206c914 (patch)
treea589cb7929bf8fcc365d37b3c746d369b50d377b
parent6147a9d8070e1c9d16d57eb53a14942b95b28dc4 (diff)
nohz: Add API to check tick state
We need some quick way to check if the CPU has stopped its tick. This will be useful to implement the printk tick using the irq work subsystem. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
-rw-r--r--include/linux/tick.h17
-rw-r--r--kernel/time/tick-sched.c2
2 files changed, 17 insertions, 2 deletions
diff --git a/include/linux/tick.h b/include/linux/tick.h
index f37fceb69b73..2307dd31b966 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -8,6 +8,8 @@
#include <linux/clockchips.h>
#include <linux/irqflags.h>
+#include <linux/percpu.h>
+#include <linux/hrtimer.h>
#ifdef CONFIG_GENERIC_CLOCKEVENTS
@@ -122,13 +124,26 @@ static inline int tick_oneshot_mode_active(void) { return 0; }
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
# ifdef CONFIG_NO_HZ
+DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);
+
+static inline int tick_nohz_tick_stopped(void)
+{
+ return __this_cpu_read(tick_cpu_sched.tick_stopped);
+}
+
extern void tick_nohz_idle_enter(void);
extern void tick_nohz_idle_exit(void);
extern void tick_nohz_irq_exit(void);
extern ktime_t tick_nohz_get_sleep_length(void);
extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
-# else
+
+# else /* !CONFIG_NO_HZ */
+static inline int tick_nohz_tick_stopped(void)
+{
+ return 0;
+}
+
static inline void tick_nohz_idle_enter(void) { }
static inline void tick_nohz_idle_exit(void) { }
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index a40260885265..9e945aa090ac 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -28,7 +28,7 @@
/*
* Per cpu nohz control structure
*/
-static DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);
+DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);
/*
* The time, when the last jiffy update happened. Protected by xtime_lock.