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-rw-r--r--include/linux/hrtimer.h7
-rw-r--r--include/linux/timer.h3
-rw-r--r--kernel/hrtimer.c7
-rw-r--r--kernel/timer.c31
4 files changed, 39 insertions, 9 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 0d2f7c8..7400900 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -30,8 +30,11 @@ struct hrtimer_cpu_base;
* Mode arguments of xxx_hrtimer functions:
*/
enum hrtimer_mode {
- HRTIMER_MODE_ABS, /* Time value is absolute */
- HRTIMER_MODE_REL, /* Time value is relative to now */
+ HRTIMER_MODE_ABS = 0x0, /* Time value is absolute */
+ HRTIMER_MODE_REL = 0x1, /* Time value is relative to now */
+ HRTIMER_MODE_PINNED = 0x02, /* Timer is bound to CPU */
+ HRTIMER_MODE_ABS_PINNED = 0x02,
+ HRTIMER_MODE_REL_PINNED = 0x03,
};
/*
diff --git a/include/linux/timer.h b/include/linux/timer.h
index 6cdb6f3..ccf882e 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -163,7 +163,10 @@ extern void add_timer_on(struct timer_list *timer, int cpu);
extern int del_timer(struct timer_list * timer);
extern int mod_timer(struct timer_list *timer, unsigned long expires);
extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
+extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
+#define TIMER_NOT_PINNED 0
+#define TIMER_PINNED 1
/*
* The jiffies value which is added to now, when there is no timer
* in the timer wheel:
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index cb8a15c..c71bcd5 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -193,7 +193,8 @@ struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
* Switch the timer base to the current CPU when possible.
*/
static inline struct hrtimer_clock_base *
-switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base)
+switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
+ int pinned)
{
struct hrtimer_clock_base *new_base;
struct hrtimer_cpu_base *new_cpu_base;
@@ -907,9 +908,9 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
ret = remove_hrtimer(timer, base);
/* Switch the timer base, if necessary: */
- new_base = switch_hrtimer_base(timer, base);
+ new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
- if (mode == HRTIMER_MODE_REL) {
+ if (mode & HRTIMER_MODE_REL) {
tim = ktime_add_safe(tim, new_base->get_time());
/*
* CONFIG_TIME_LOW_RES is a temporary way for architectures
diff --git a/kernel/timer.c b/kernel/timer.c
index 5c1e84b..3424dfd 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -604,7 +604,8 @@ static struct tvec_base *lock_timer_base(struct timer_list *timer,
}
static inline int
-__mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only)
+__mod_timer(struct timer_list *timer, unsigned long expires,
+ bool pending_only, int pinned)
{
struct tvec_base *base, *new_base;
unsigned long flags;
@@ -668,7 +669,7 @@ out_unlock:
*/
int mod_timer_pending(struct timer_list *timer, unsigned long expires)
{
- return __mod_timer(timer, expires, true);
+ return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
}
EXPORT_SYMBOL(mod_timer_pending);
@@ -702,11 +703,33 @@ int mod_timer(struct timer_list *timer, unsigned long expires)
if (timer->expires == expires && timer_pending(timer))
return 1;
- return __mod_timer(timer, expires, false);
+ return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
}
EXPORT_SYMBOL(mod_timer);
/**
+ * mod_timer_pinned - modify a timer's timeout
+ * @timer: the timer to be modified
+ * @expires: new timeout in jiffies
+ *
+ * mod_timer_pinned() is a way to update the expire field of an
+ * active timer (if the timer is inactive it will be activated)
+ * and not allow the timer to be migrated to a different CPU.
+ *
+ * mod_timer_pinned(timer, expires) is equivalent to:
+ *
+ * del_timer(timer); timer->expires = expires; add_timer(timer);
+ */
+int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
+{
+ if (timer->expires == expires && timer_pending(timer))
+ return 1;
+
+ return __mod_timer(timer, expires, false, TIMER_PINNED);
+}
+EXPORT_SYMBOL(mod_timer_pinned);
+
+/**
* add_timer - start a timer
* @timer: the timer to be added
*
@@ -1356,7 +1379,7 @@ signed long __sched schedule_timeout(signed long timeout)
expire = timeout + jiffies;
setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
- __mod_timer(&timer, expire, false);
+ __mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
schedule();
del_singleshot_timer_sync(&timer);