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Subject[PATCH 2/7] [RFC] hrtimers: Convert hrtimers to use timerlist infrastructure
Date
Converts the hrtimer code to use the timerlist infrastructure

Survived some light testing, but there may still be bugs.

Signed-off-by: John Stultz <john.stultz@linaro.org>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Richard Cochran <richardcochran@gmail.com>
CC: Arve Hjønnevåg <arve@android.com>
---
include/linux/hrtimer.h | 32 ++++++++---------
kernel/hrtimer.c | 86 ++++++++++++++++------------------------------
kernel/time/timer_list.c | 8 ++--
3 files changed, 49 insertions(+), 77 deletions(-)

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index fd0c1b8..019ac70 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -22,7 +22,7 @@
#include <linux/wait.h>
#include <linux/percpu.h>
#include <linux/timer.h>
-
+#include <linux/timerlist.h>

struct hrtimer_clock_base;
struct hrtimer_cpu_base;
@@ -79,8 +79,8 @@ enum hrtimer_restart {

/**
* struct hrtimer - the basic hrtimer structure
- * @node: red black tree node for time ordered insertion
- * @_expires: the absolute expiry time in the hrtimers internal
+ * @node: timerlist node, which also manages node.expires,
+ * the absolute expiry time in the hrtimers internal
* representation. The time is related to the clock on
* which the timer is based. Is setup by adding
* slack to the _softexpires value. For non range timers
@@ -101,8 +101,7 @@ enum hrtimer_restart {
* The hrtimer structure must be initialized by hrtimer_init()
*/
struct hrtimer {
- struct rb_node node;
- ktime_t _expires;
+ struct timerlist_node node;
ktime_t _softexpires;
enum hrtimer_restart (*function)(struct hrtimer *);
struct hrtimer_clock_base *base;
@@ -141,8 +140,7 @@ struct hrtimer_sleeper {
struct hrtimer_clock_base {
struct hrtimer_cpu_base *cpu_base;
clockid_t index;
- struct rb_root active;
- struct rb_node *first;
+ struct timerlist_head active;
ktime_t resolution;
ktime_t (*get_time)(void);
ktime_t softirq_time;
@@ -184,43 +182,43 @@ struct hrtimer_cpu_base {

static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
{
- timer->_expires = time;
+ timer->node.expires = time;
timer->_softexpires = time;
}

static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
{
timer->_softexpires = time;
- timer->_expires = ktime_add_safe(time, delta);
+ timer->node.expires = ktime_add_safe(time, delta);
}

static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)
{
timer->_softexpires = time;
- timer->_expires = ktime_add_safe(time, ns_to_ktime(delta));
+ timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
}

static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
{
- timer->_expires.tv64 = tv64;
+ timer->node.expires.tv64 = tv64;
timer->_softexpires.tv64 = tv64;
}

static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
{
- timer->_expires = ktime_add_safe(timer->_expires, time);
+ timer->node.expires = ktime_add_safe(timer->node.expires, time);
timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
}

static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
{
- timer->_expires = ktime_add_ns(timer->_expires, ns);
+ timer->node.expires = ktime_add_ns(timer->node.expires, ns);
timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
}

static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
{
- return timer->_expires;
+ return timer->node.expires;
}

static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
@@ -230,7 +228,7 @@ static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)

static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
{
- return timer->_expires.tv64;
+ return timer->node.expires.tv64;
}
static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
{
@@ -239,12 +237,12 @@ static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)

static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
{
- return ktime_to_ns(timer->_expires);
+ return ktime_to_ns(timer->node.expires);
}

static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
{
- return ktime_sub(timer->_expires, timer->base->get_time());
+ return ktime_sub(timer->node.expires, timer->base->get_time());
}

#ifdef CONFIG_HIGH_RES_TIMERS
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 72206cf..d31ad88 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -516,10 +516,13 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)

for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
struct hrtimer *timer;
+ struct timerlist_node *next;

- if (!base->first)
+ next = timerlist_getnext(&base->active);
+ if (!next)
continue;
- timer = rb_entry(base->first, struct hrtimer, node);
+ timer = container_of(next, struct hrtimer, node);
+
expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
/*
* clock_was_set() has changed base->offset so the
@@ -840,48 +843,17 @@ EXPORT_SYMBOL_GPL(hrtimer_forward);
static int enqueue_hrtimer(struct hrtimer *timer,
struct hrtimer_clock_base *base)
{
- struct rb_node **link = &base->active.rb_node;
- struct rb_node *parent = NULL;
- struct hrtimer *entry;
- int leftmost = 1;
-
debug_activate(timer);

- /*
- * Find the right place in the rbtree:
- */
- while (*link) {
- parent = *link;
- entry = rb_entry(parent, struct hrtimer, node);
- /*
- * We dont care about collisions. Nodes with
- * the same expiry time stay together.
- */
- if (hrtimer_get_expires_tv64(timer) <
- hrtimer_get_expires_tv64(entry)) {
- link = &(*link)->rb_left;
- } else {
- link = &(*link)->rb_right;
- leftmost = 0;
- }
- }
+ timerlist_add(&base->active, &timer->node);

/*
- * Insert the timer to the rbtree and check whether it
- * replaces the first pending timer
- */
- if (leftmost)
- base->first = &timer->node;
-
- rb_link_node(&timer->node, parent, link);
- rb_insert_color(&timer->node, &base->active);
- /*
* HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
* state of a possibly running callback.
*/
timer->state |= HRTIMER_STATE_ENQUEUED;

- return leftmost;
+ return (&timer->node == base->active.next);
}

/*
@@ -901,12 +873,7 @@ static void __remove_hrtimer(struct hrtimer *timer,
if (!(timer->state & HRTIMER_STATE_ENQUEUED))
goto out;

- /*
- * Remove the timer from the rbtree and replace the first
- * entry pointer if necessary.
- */
- if (base->first == &timer->node) {
- base->first = rb_next(&timer->node);
+ if (&timer->node == timerlist_getnext(&base->active)) {
#ifdef CONFIG_HIGH_RES_TIMERS
/* Reprogram the clock event device. if enabled */
if (reprogram && hrtimer_hres_active()) {
@@ -919,7 +886,7 @@ static void __remove_hrtimer(struct hrtimer *timer,
}
#endif
}
- rb_erase(&timer->node, &base->active);
+ timerlist_del(&base->active, &timer->node);
out:
timer->state = newstate;
}
@@ -1128,11 +1095,13 @@ ktime_t hrtimer_get_next_event(void)
if (!hrtimer_hres_active()) {
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
struct hrtimer *timer;
+ struct timerlist_node *next;

- if (!base->first)
+ next = timerlist_getnext(&base->active);
+ if (!next)
continue;

- timer = rb_entry(base->first, struct hrtimer, node);
+ timer = container_of(next, struct hrtimer, node);
delta.tv64 = hrtimer_get_expires_tv64(timer);
delta = ktime_sub(delta, base->get_time());
if (delta.tv64 < mindelta.tv64)
@@ -1162,6 +1131,7 @@ static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,

timer->base = &cpu_base->clock_base[clock_id];
hrtimer_init_timer_hres(timer);
+ timerlist_init(&timer->node);

#ifdef CONFIG_TIMER_STATS
timer->start_site = NULL;
@@ -1278,14 +1248,14 @@ retry:

for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
ktime_t basenow;
- struct rb_node *node;
+ struct timerlist_node *node;

basenow = ktime_add(now, base->offset);

- while ((node = base->first)) {
+ while ((node = timerlist_getnext(&base->active))) {
struct hrtimer *timer;

- timer = rb_entry(node, struct hrtimer, node);
+ timer = container_of(node, struct hrtimer, node);

/*
* The immediate goal for using the softexpires is
@@ -1441,7 +1411,7 @@ void hrtimer_run_pending(void)
*/
void hrtimer_run_queues(void)
{
- struct rb_node *node;
+ struct timerlist_node *node;
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
struct hrtimer_clock_base *base;
int index, gettime = 1;
@@ -1450,9 +1420,11 @@ void hrtimer_run_queues(void)
return;

for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
- base = &cpu_base->clock_base[index];
+ struct timerlist_node *next;

- if (!base->first)
+ base = &cpu_base->clock_base[index];
+ next = timerlist_getnext(&base->active);
+ if (!next)
continue;

if (gettime) {
@@ -1462,10 +1434,10 @@ void hrtimer_run_queues(void)

raw_spin_lock(&cpu_base->lock);

- while ((node = base->first)) {
+ while ((node = next)) {
struct hrtimer *timer;

- timer = rb_entry(node, struct hrtimer, node);
+ timer = container_of(node, struct hrtimer, node);
if (base->softirq_time.tv64 <=
hrtimer_get_expires_tv64(timer))
break;
@@ -1630,8 +1602,10 @@ static void __cpuinit init_hrtimers_cpu(int cpu)

raw_spin_lock_init(&cpu_base->lock);

- for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
cpu_base->clock_base[i].cpu_base = cpu_base;
+ timerlist_init_head(&cpu_base->clock_base[i].active);
+ }

hrtimer_init_hres(cpu_base);
}
@@ -1642,10 +1616,10 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
struct hrtimer_clock_base *new_base)
{
struct hrtimer *timer;
- struct rb_node *node;
+ struct timerlist_node *node;

- while ((node = rb_first(&old_base->active))) {
- timer = rb_entry(node, struct hrtimer, node);
+ while ((node = timerlist_getnext(&old_base->active))) {
+ timer = container_of(node, struct hrtimer, node);
BUG_ON(hrtimer_callback_running(timer));
debug_deactivate(timer);

diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index ab8f5e3..7583b8d 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -79,26 +79,26 @@ print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
{
struct hrtimer *timer, tmp;
unsigned long next = 0, i;
- struct rb_node *curr;
+ struct timerlist_node *curr;
unsigned long flags;

next_one:
i = 0;
raw_spin_lock_irqsave(&base->cpu_base->lock, flags);

- curr = base->first;
+ curr = timerlist_getnext(&base->active);
/*
* Crude but we have to do this O(N*N) thing, because
* we have to unlock the base when printing:
*/
while (curr && i < next) {
- curr = rb_next(curr);
+ curr = timerlist_iterate_next(curr);
i++;
}

if (curr) {

- timer = rb_entry(curr, struct hrtimer, node);
+ timer = container_of(curr, struct hrtimer, node);
tmp = *timer;
raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);

--
1.7.3.2.146.gca209
--
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