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-rw-r--r--include/linux/sched.h17
-rw-r--r--kernel/sched_clock.c109
-rw-r--r--kernel/time/tick-sched.c2
3 files changed, 14 insertions, 114 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5270d449ff9..ea436bc1a0e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1572,28 +1572,13 @@ static inline void sched_clock_idle_sleep_event(void)
static inline void sched_clock_idle_wakeup_event(u64 delta_ns)
{
}
-
-#ifdef CONFIG_NO_HZ
-static inline void sched_clock_tick_stop(int cpu)
-{
-}
-
-static inline void sched_clock_tick_start(int cpu)
-{
-}
-#endif
-
-#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
+#else
extern void sched_clock_init(void);
extern u64 sched_clock_cpu(int cpu);
extern void sched_clock_tick(void);
extern void sched_clock_idle_sleep_event(void);
extern void sched_clock_idle_wakeup_event(u64 delta_ns);
-#ifdef CONFIG_NO_HZ
-extern void sched_clock_tick_stop(int cpu);
-extern void sched_clock_tick_start(int cpu);
#endif
-#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
/*
* For kernel-internal use: high-speed (but slightly incorrect) per-cpu
diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index 5a2dc7d8fd9..9a7844158ae 100644
--- a/kernel/sched_clock.c
+++ b/kernel/sched_clock.c
@@ -44,11 +44,6 @@ unsigned long long __attribute__((weak)) sched_clock(void)
#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
-#define MULTI_SHIFT 15
-/* Max is double, Min is 1/2 */
-#define MAX_MULTI (2LL << MULTI_SHIFT)
-#define MIN_MULTI (1LL << (MULTI_SHIFT-1))
-
struct sched_clock_data {
/*
* Raw spinlock - this is a special case: this might be called
@@ -62,10 +57,6 @@ struct sched_clock_data {
u64 tick_raw;
u64 tick_gtod;
u64 clock;
- s64 multi;
-#ifdef CONFIG_NO_HZ
- int check_max;
-#endif
};
static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);
@@ -97,53 +88,18 @@ void sched_clock_init(void)
scd->tick_raw = 0;
scd->tick_gtod = ktime_now;
scd->clock = ktime_now;
- scd->multi = 1 << MULTI_SHIFT;
-#ifdef CONFIG_NO_HZ
- scd->check_max = 1;
-#endif
}
sched_clock_running = 1;
}
-#ifdef CONFIG_NO_HZ
-/*
- * The dynamic ticks makes the delta jiffies inaccurate. This
- * prevents us from checking the maximum time update.
- * Disable the maximum check during stopped ticks.
- */
-void sched_clock_tick_stop(int cpu)
-{
- struct sched_clock_data *scd = cpu_sdc(cpu);
-
- scd->check_max = 0;
-}
-
-void sched_clock_tick_start(int cpu)
-{
- struct sched_clock_data *scd = cpu_sdc(cpu);
-
- scd->check_max = 1;
-}
-
-static int check_max(struct sched_clock_data *scd)
-{
- return scd->check_max;
-}
-#else
-static int check_max(struct sched_clock_data *scd)
-{
- return 1;
-}
-#endif /* CONFIG_NO_HZ */
-
/*
* update the percpu scd from the raw @now value
*
* - filter out backward motion
* - use jiffies to generate a min,max window to clip the raw values
*/
-static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *time)
+static void __update_sched_clock(struct sched_clock_data *scd, u64 now)
{
unsigned long now_jiffies = jiffies;
long delta_jiffies = now_jiffies - scd->tick_jiffies;
@@ -152,31 +108,16 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *tim
s64 delta = now - scd->prev_raw;
WARN_ON_ONCE(!irqs_disabled());
-
- /*
- * At schedule tick the clock can be just under the gtod. We don't
- * want to push it too prematurely.
- */
- min_clock = scd->tick_gtod + (delta_jiffies * TICK_NSEC);
- if (min_clock > TICK_NSEC)
- min_clock -= TICK_NSEC / 2;
+ min_clock = scd->tick_gtod + delta_jiffies * TICK_NSEC;
if (unlikely(delta < 0)) {
clock++;
goto out;
}
- /*
- * The clock must stay within a jiffie of the gtod.
- * But since we may be at the start of a jiffy or the end of one
- * we add another jiffy buffer.
- */
- max_clock = scd->tick_gtod + (2 + delta_jiffies) * TICK_NSEC;
-
- delta *= scd->multi;
- delta >>= MULTI_SHIFT;
+ max_clock = min_clock + TICK_NSEC;
- if (unlikely(clock + delta > max_clock) && check_max(scd)) {
+ if (unlikely(clock + delta > max_clock)) {
if (clock < max_clock)
clock = max_clock;
else
@@ -189,12 +130,9 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *tim
if (unlikely(clock < min_clock))
clock = min_clock;
- if (time)
- *time = clock;
- else {
- scd->prev_raw = now;
- scd->clock = clock;
- }
+ scd->prev_raw = now;
+ scd->tick_jiffies = now_jiffies;
+ scd->clock = clock;
}
static void lock_double_clock(struct sched_clock_data *data1,
@@ -238,26 +176,21 @@ u64 sched_clock_cpu(int cpu)
now -= scd->tick_gtod;
__raw_spin_unlock(&my_scd->lock);
-
- __update_sched_clock(scd, now, &clock);
-
- __raw_spin_unlock(&scd->lock);
-
} else {
__raw_spin_lock(&scd->lock);
- __update_sched_clock(scd, now, NULL);
- clock = scd->clock;
- __raw_spin_unlock(&scd->lock);
}
+ __update_sched_clock(scd, now);
+ clock = scd->clock;
+
+ __raw_spin_unlock(&scd->lock);
+
return clock;
}
void sched_clock_tick(void)
{
struct sched_clock_data *scd = this_scd();
- unsigned long now_jiffies = jiffies;
- s64 mult, delta_gtod, delta_raw;
u64 now, now_gtod;
if (unlikely(!sched_clock_running))
@@ -269,29 +202,14 @@ void sched_clock_tick(void)
now = sched_clock();
__raw_spin_lock(&scd->lock);
- __update_sched_clock(scd, now, NULL);
+ __update_sched_clock(scd, now);
/*
* update tick_gtod after __update_sched_clock() because that will
* already observe 1 new jiffy; adding a new tick_gtod to that would
* increase the clock 2 jiffies.
*/
- delta_gtod = now_gtod - scd->tick_gtod;
- delta_raw = now - scd->tick_raw;
-
- if ((long)delta_raw > 0) {
- mult = delta_gtod << MULTI_SHIFT;
- do_div(mult, delta_raw);
- scd->multi = mult;
- if (scd->multi > MAX_MULTI)
- scd->multi = MAX_MULTI;
- else if (scd->multi < MIN_MULTI)
- scd->multi = MIN_MULTI;
- } else
- scd->multi = 1 << MULTI_SHIFT;
-
scd->tick_raw = now;
scd->tick_gtod = now_gtod;
- scd->tick_jiffies = now_jiffies;
__raw_spin_unlock(&scd->lock);
}
@@ -321,7 +239,6 @@ void sched_clock_idle_wakeup_event(u64 delta_ns)
__raw_spin_lock(&scd->lock);
scd->prev_raw = now;
scd->clock += delta_ns;
- scd->multi = 1 << MULTI_SHIFT;
__raw_spin_unlock(&scd->lock);
touch_softlockup_watchdog();
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 825b4c00fe4..f5da526424a 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -289,7 +289,6 @@ void tick_nohz_stop_sched_tick(int inidle)
ts->tick_stopped = 1;
ts->idle_jiffies = last_jiffies;
rcu_enter_nohz();
- sched_clock_tick_stop(cpu);
}
/*
@@ -392,7 +391,6 @@ void tick_nohz_restart_sched_tick(void)
select_nohz_load_balancer(0);
now = ktime_get();
tick_do_update_jiffies64(now);
- sched_clock_tick_start(cpu);
cpu_clear(cpu, nohz_cpu_mask);
/*
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 21:17:10 +0000