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Diffstat (limited to 'kernel/timer.c')
-rw-r--r--kernel/timer.c51
1 files changed, 44 insertions, 7 deletions
diff --git a/kernel/timer.c b/kernel/timer.c
index faf2db897de..54d3912f8ca 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -38,6 +38,7 @@
#include <linux/tick.h>
#include <linux/kallsyms.h>
#include <linux/perf_counter.h>
+#include <linux/sched.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -605,13 +606,12 @@ 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;
- int ret;
-
- ret = 0;
+ int ret = 0 , cpu;
timer_stats_timer_set_start_info(timer);
BUG_ON(!timer->function);
@@ -630,6 +630,18 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only)
new_base = __get_cpu_var(tvec_bases);
+ cpu = smp_processor_id();
+
+#if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
+ if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu)) {
+ int preferred_cpu = get_nohz_load_balancer();
+
+ if (preferred_cpu >= 0)
+ cpu = preferred_cpu;
+ }
+#endif
+ new_base = per_cpu(tvec_bases, cpu);
+
if (base != new_base) {
/*
* We are trying to schedule the timer on the local CPU.
@@ -669,7 +681,7 @@ 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);
@@ -703,11 +715,33 @@ 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
*
@@ -1017,6 +1051,9 @@ cascade:
index = slot = timer_jiffies & TVN_MASK;
do {
list_for_each_entry(nte, varp->vec + slot, entry) {
+ if (tbase_get_deferrable(nte->base))
+ continue;
+
found = 1;
if (time_before(nte->expires, expires))
expires = nte->expires;
@@ -1307,7 +1344,7 @@ 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);