summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--include/linux/clocksource.h1
-rw-r--r--kernel/time/clocksource.c57
2 files changed, 43 insertions, 15 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 2f39a4911668..dbbf8aa7731b 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -210,6 +210,7 @@ struct clocksource {
#define CLOCK_SOURCE_VALID_FOR_HRES 0x20
#define CLOCK_SOURCE_UNSTABLE 0x40
#define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80
+#define CLOCK_SOURCE_RESELECT 0x100
/* simplify initialization of mask field */
#define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index e713ef7d19a7..50a8736757f3 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -181,6 +181,7 @@ static int finished_booting;
#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
static void clocksource_watchdog_work(struct work_struct *work);
+static void clocksource_select(void);
static LIST_HEAD(watchdog_list);
static struct clocksource *watchdog;
@@ -301,13 +302,30 @@ static void clocksource_watchdog(unsigned long data)
if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) &&
(cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
(watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) {
+ /* Mark it valid for high-res. */
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
+
+ /*
+ * clocksource_done_booting() will sort it if
+ * finished_booting is not set yet.
+ */
+ if (!finished_booting)
+ continue;
+
/*
- * We just marked the clocksource as highres-capable,
- * notify the rest of the system as well so that we
- * transition into high-res mode:
+ * If this is not the current clocksource let
+ * the watchdog thread reselect it. Due to the
+ * change to high res this clocksource might
+ * be preferred now. If it is the current
+ * clocksource let the tick code know about
+ * that change.
*/
- tick_clock_notify();
+ if (cs != curr_clocksource) {
+ cs->flags |= CLOCK_SOURCE_RESELECT;
+ schedule_work(&watchdog_work);
+ } else {
+ tick_clock_notify();
+ }
}
}
@@ -404,19 +422,25 @@ static void clocksource_dequeue_watchdog(struct clocksource *cs)
spin_unlock_irqrestore(&watchdog_lock, flags);
}
-static int clocksource_watchdog_kthread(void *data)
+static int __clocksource_watchdog_kthread(void)
{
struct clocksource *cs, *tmp;
unsigned long flags;
LIST_HEAD(unstable);
+ int select = 0;
- mutex_lock(&clocksource_mutex);
spin_lock_irqsave(&watchdog_lock, flags);
- list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list)
+ list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) {
if (cs->flags & CLOCK_SOURCE_UNSTABLE) {
list_del_init(&cs->wd_list);
list_add(&cs->wd_list, &unstable);
+ select = 1;
+ }
+ if (cs->flags & CLOCK_SOURCE_RESELECT) {
+ cs->flags &= ~CLOCK_SOURCE_RESELECT;
+ select = 1;
}
+ }
/* Check if the watchdog timer needs to be stopped. */
clocksource_stop_watchdog();
spin_unlock_irqrestore(&watchdog_lock, flags);
@@ -426,6 +450,14 @@ static int clocksource_watchdog_kthread(void *data)
list_del_init(&cs->wd_list);
__clocksource_change_rating(cs, 0);
}
+ return select;
+}
+
+static int clocksource_watchdog_kthread(void *data)
+{
+ mutex_lock(&clocksource_mutex);
+ if (__clocksource_watchdog_kthread())
+ clocksource_select();
mutex_unlock(&clocksource_mutex);
return 0;
}
@@ -445,7 +477,7 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs)
static inline void clocksource_dequeue_watchdog(struct clocksource *cs) { }
static inline void clocksource_resume_watchdog(void) { }
-static inline int clocksource_watchdog_kthread(void *data) { return 0; }
+static inline int __clocksource_watchdog_kthread(void) { return 0; }
static bool clocksource_is_watchdog(struct clocksource *cs) { return false; }
#endif /* CONFIG_CLOCKSOURCE_WATCHDOG */
@@ -647,16 +679,11 @@ static int __init clocksource_done_booting(void)
{
mutex_lock(&clocksource_mutex);
curr_clocksource = clocksource_default_clock();
- mutex_unlock(&clocksource_mutex);
-
finished_booting = 1;
-
/*
* Run the watchdog first to eliminate unstable clock sources
*/
- clocksource_watchdog_kthread(NULL);
-
- mutex_lock(&clocksource_mutex);
+ __clocksource_watchdog_kthread();
clocksource_select();
mutex_unlock(&clocksource_mutex);
return 0;
@@ -789,7 +816,6 @@ static void __clocksource_change_rating(struct clocksource *cs, int rating)
list_del(&cs->list);
cs->rating = rating;
clocksource_enqueue(cs);
- clocksource_select();
}
/**
@@ -801,6 +827,7 @@ void clocksource_change_rating(struct clocksource *cs, int rating)
{
mutex_lock(&clocksource_mutex);
__clocksource_change_rating(cs, rating);
+ clocksource_select();
mutex_unlock(&clocksource_mutex);
}
EXPORT_SYMBOL(clocksource_change_rating);