There are various places where we are currently running a loop of
HRTIMER_MAX_CLOCK_BASES iterations. We just run 'continue;' if there are no
timers added to a clock base. Instead we can use the new for_each_active_base()
routine to iterate over only the bases which are currently active.

Signed-off-by: Viresh Kumar <[email protected]>
---
 kernel/hrtimer.c | 58 ++++++++++++++++++++++----------------------------------
 1 file changed, 23 insertions(+), 35 deletions(-)

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index ceadfa5..b3ab19a 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -557,21 +557,17 @@ static inline int hrtimer_hres_active(void)
 static void
 hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
 {
-       int i;
-       struct hrtimer_clock_base *base = cpu_base->clock_base;
+       struct hrtimer_clock_base *base;
+       struct hrtimer *timer;
        ktime_t expires, expires_next;
+       unsigned int active_bases;
+       int i;
 
        expires_next.tv64 = KTIME_MAX;
 
-       for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
-               struct hrtimer *timer;
-               struct timerqueue_node *next;
-
-               next = timerqueue_getnext(&base->active);
-               if (!next)
-                       continue;
-               timer = container_of(next, struct hrtimer, node);
-
+       for_each_active_base(i, base, cpu_base, active_bases) {
+               timer = container_of(timerqueue_getnext(&base->active),
+                                    struct hrtimer, node);
                expires = hrtimer_get_monoexpires(timer, base);
                /*
                 * clock_was_set() has changed base->offset so the
@@ -1131,23 +1127,19 @@ EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
 ktime_t hrtimer_get_next_event(void)
 {
        struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
-       struct hrtimer_clock_base *base = cpu_base->clock_base;
+       struct hrtimer_clock_base *base;
        ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
+       struct hrtimer *timer;
+       unsigned int active_bases;
        unsigned long flags;
        int i;
 
        raw_spin_lock_irqsave(&cpu_base->lock, flags);
 
        if (!hrtimer_hres_active()) {
-               for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
-                       struct hrtimer *timer;
-                       struct timerqueue_node *next;
-
-                       next = timerqueue_getnext(&base->active);
-                       if (!next)
-                               continue;
-
-                       timer = container_of(next, struct hrtimer, node);
+               for_each_active_base(i, base, cpu_base, active_bases) {
+                       timer = container_of(timerqueue_getnext(&base->active),
+                                            struct hrtimer, node);
                        delta.tv64 = hrtimer_get_expires_tv64(timer);
                        delta = ktime_sub(delta, base->get_time());
                        if (delta.tv64 < mindelta.tv64)
@@ -1270,7 +1262,9 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t 
*now)
 void hrtimer_interrupt(struct clock_event_device *dev)
 {
        struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+       struct hrtimer_clock_base *base;
        ktime_t expires_next, now, entry_time, delta;
+       unsigned int active_bases;
        int i, retries = 0;
 
        BUG_ON(!cpu_base->hres_active);
@@ -1290,15 +1284,10 @@ retry:
         */
        cpu_base->expires_next.tv64 = KTIME_MAX;
 
-       for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
-               struct hrtimer_clock_base *base;
+       for_each_active_base(i, base, cpu_base, active_bases) {
                struct timerqueue_node *node;
                ktime_t basenow;
 
-               if (!(cpu_base->active_bases & (1 << i)))
-                       continue;
-
-               base = cpu_base->clock_base + i;
                basenow = ktime_add(now, base->offset);
 
                while ((node = timerqueue_getnext(&base->active))) {
@@ -1468,16 +1457,13 @@ void hrtimer_run_queues(void)
        struct timerqueue_node *node;
        struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
        struct hrtimer_clock_base *base;
+       unsigned int active_bases;
        int index, gettime = 1;
 
        if (hrtimer_hres_active())
                return;
 
-       for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
-               base = &cpu_base->clock_base[index];
-               if (!timerqueue_getnext(&base->active))
-                       continue;
-
+       for_each_active_base(index, base, cpu_base, active_bases) {
                if (gettime) {
                        hrtimer_get_softirq_time(cpu_base);
                        gettime = 0;
@@ -1697,6 +1683,8 @@ static void migrate_hrtimer_list(struct 
hrtimer_clock_base *old_base,
 static void migrate_hrtimers(int scpu)
 {
        struct hrtimer_cpu_base *old_base, *new_base;
+       struct hrtimer_clock_base *clock_base;
+       unsigned int active_bases;
        int i;
 
        BUG_ON(cpu_online(scpu));
@@ -1712,9 +1700,9 @@ static void migrate_hrtimers(int scpu)
        raw_spin_lock(&new_base->lock);
        raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
 
-       for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
-               migrate_hrtimer_list(&old_base->clock_base[i],
-                                    &new_base->clock_base[i]);
+       for_each_active_base(i, clock_base, old_base, active_bases)
+               migrate_hrtimer_list(clock_base,
+                                    &new_base->clock_base[clock_base->index]);
 
        raw_spin_unlock(&old_base->lock);
        raw_spin_unlock(&new_base->lock);
-- 
1.7.12.rc2.18.g61b472e

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