Merge branch 'sched/clock' into sched/urgent
This commit is contained in:
Ingo Molnar
Коммит
e26b33e955
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@ -1551,16 +1551,10 @@ static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask)
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extern unsigned long long sched_clock(void);
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extern void sched_clock_init(void);
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extern u64 sched_clock_cpu(int cpu);
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#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
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static inline void sched_clock_init(void)
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{
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}
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static inline u64 sched_clock_cpu(int cpu)
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{
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return sched_clock();
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}
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static inline void sched_clock_tick(void)
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{
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}
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@ -1572,28 +1566,11 @@ static inline void sched_clock_idle_sleep_event(void)
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static inline void sched_clock_idle_wakeup_event(u64 delta_ns)
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{
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}
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#ifdef CONFIG_NO_HZ
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static inline void sched_clock_tick_stop(int cpu)
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{
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}
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static inline void sched_clock_tick_start(int cpu)
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{
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}
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#endif
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#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
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extern void sched_clock_init(void);
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extern u64 sched_clock_cpu(int cpu);
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#else
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extern void sched_clock_tick(void);
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extern void sched_clock_idle_sleep_event(void);
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extern void sched_clock_idle_wakeup_event(u64 delta_ns);
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#ifdef CONFIG_NO_HZ
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extern void sched_clock_tick_stop(int cpu);
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extern void sched_clock_tick_start(int cpu);
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#endif
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#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
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/*
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* For kernel-internal use: high-speed (but slightly incorrect) per-cpu
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@ -42,12 +42,9 @@ unsigned long long __attribute__((weak)) sched_clock(void)
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return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
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}
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#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
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static __read_mostly int sched_clock_running;
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#define MULTI_SHIFT 15
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/* Max is double, Min is 1/2 */
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#define MAX_MULTI (2LL << MULTI_SHIFT)
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#define MIN_MULTI (1LL << (MULTI_SHIFT-1))
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#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
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struct sched_clock_data {
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/*
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@ -58,14 +55,9 @@ struct sched_clock_data {
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raw_spinlock_t lock;
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unsigned long tick_jiffies;
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u64 prev_raw;
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u64 tick_raw;
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u64 tick_gtod;
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u64 clock;
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s64 multi;
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#ifdef CONFIG_NO_HZ
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int check_max;
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#endif
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};
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static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);
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@ -80,8 +72,6 @@ static inline struct sched_clock_data *cpu_sdc(int cpu)
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return &per_cpu(sched_clock_data, cpu);
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}
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static __read_mostly int sched_clock_running;
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void sched_clock_init(void)
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{
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u64 ktime_now = ktime_to_ns(ktime_get());
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@ -93,90 +83,39 @@ void sched_clock_init(void)
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scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
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scd->tick_jiffies = now_jiffies;
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scd->prev_raw = 0;
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scd->tick_raw = 0;
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scd->tick_gtod = ktime_now;
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scd->clock = ktime_now;
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scd->multi = 1 << MULTI_SHIFT;
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#ifdef CONFIG_NO_HZ
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scd->check_max = 1;
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#endif
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}
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sched_clock_running = 1;
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}
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#ifdef CONFIG_NO_HZ
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/*
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* The dynamic ticks makes the delta jiffies inaccurate. This
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* prevents us from checking the maximum time update.
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* Disable the maximum check during stopped ticks.
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*/
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void sched_clock_tick_stop(int cpu)
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{
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struct sched_clock_data *scd = cpu_sdc(cpu);
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scd->check_max = 0;
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}
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void sched_clock_tick_start(int cpu)
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{
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struct sched_clock_data *scd = cpu_sdc(cpu);
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scd->check_max = 1;
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}
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static int check_max(struct sched_clock_data *scd)
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{
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return scd->check_max;
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}
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#else
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static int check_max(struct sched_clock_data *scd)
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{
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return 1;
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}
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#endif /* CONFIG_NO_HZ */
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/*
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* update the percpu scd from the raw @now value
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*
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* - filter out backward motion
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* - use jiffies to generate a min,max window to clip the raw values
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*/
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static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *time)
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static u64 __update_sched_clock(struct sched_clock_data *scd, u64 now)
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{
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unsigned long now_jiffies = jiffies;
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long delta_jiffies = now_jiffies - scd->tick_jiffies;
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u64 clock = scd->clock;
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u64 min_clock, max_clock;
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s64 delta = now - scd->prev_raw;
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s64 delta = now - scd->tick_raw;
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WARN_ON_ONCE(!irqs_disabled());
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/*
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* At schedule tick the clock can be just under the gtod. We don't
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* want to push it too prematurely.
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*/
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min_clock = scd->tick_gtod + (delta_jiffies * TICK_NSEC);
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if (min_clock > TICK_NSEC)
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min_clock -= TICK_NSEC / 2;
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min_clock = scd->tick_gtod + delta_jiffies * TICK_NSEC;
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if (unlikely(delta < 0)) {
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clock++;
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goto out;
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}
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/*
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* The clock must stay within a jiffie of the gtod.
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* But since we may be at the start of a jiffy or the end of one
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* we add another jiffy buffer.
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*/
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max_clock = scd->tick_gtod + (2 + delta_jiffies) * TICK_NSEC;
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max_clock = min_clock + TICK_NSEC;
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delta *= scd->multi;
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delta >>= MULTI_SHIFT;
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if (unlikely(clock + delta > max_clock) && check_max(scd)) {
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if (unlikely(clock + delta > max_clock)) {
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if (clock < max_clock)
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clock = max_clock;
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else
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@ -189,12 +128,10 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *tim
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if (unlikely(clock < min_clock))
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clock = min_clock;
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if (time)
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*time = clock;
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else {
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scd->prev_raw = now;
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scd->clock = clock;
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}
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scd->tick_jiffies = now_jiffies;
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scd->clock = clock;
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return clock;
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}
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static void lock_double_clock(struct sched_clock_data *data1,
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@ -212,7 +149,7 @@ static void lock_double_clock(struct sched_clock_data *data1,
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u64 sched_clock_cpu(int cpu)
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{
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struct sched_clock_data *scd = cpu_sdc(cpu);
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u64 now, clock;
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u64 now, clock, this_clock, remote_clock;
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if (unlikely(!sched_clock_running))
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return 0ull;
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@ -221,43 +158,44 @@ u64 sched_clock_cpu(int cpu)
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now = sched_clock();
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if (cpu != raw_smp_processor_id()) {
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/*
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* in order to update a remote cpu's clock based on our
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* unstable raw time rebase it against:
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* tick_raw (offset between raw counters)
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* tick_gotd (tick offset between cpus)
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*/
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struct sched_clock_data *my_scd = this_scd();
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lock_double_clock(scd, my_scd);
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now -= my_scd->tick_raw;
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now += scd->tick_raw;
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this_clock = __update_sched_clock(my_scd, now);
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remote_clock = scd->clock;
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now += my_scd->tick_gtod;
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now -= scd->tick_gtod;
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/*
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* Use the opportunity that we have both locks
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* taken to couple the two clocks: we take the
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* larger time as the latest time for both
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* runqueues. (this creates monotonic movement)
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*/
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if (likely(remote_clock < this_clock)) {
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clock = this_clock;
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scd->clock = clock;
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} else {
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/*
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* Should be rare, but possible:
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*/
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clock = remote_clock;
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my_scd->clock = remote_clock;
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}
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__raw_spin_unlock(&my_scd->lock);
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__update_sched_clock(scd, now, &clock);
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__raw_spin_unlock(&scd->lock);
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} else {
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__raw_spin_lock(&scd->lock);
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__update_sched_clock(scd, now, NULL);
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clock = scd->clock;
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__raw_spin_unlock(&scd->lock);
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clock = __update_sched_clock(scd, now);
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}
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__raw_spin_unlock(&scd->lock);
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return clock;
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}
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void sched_clock_tick(void)
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{
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struct sched_clock_data *scd = this_scd();
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unsigned long now_jiffies = jiffies;
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s64 mult, delta_gtod, delta_raw;
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u64 now, now_gtod;
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if (unlikely(!sched_clock_running))
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@ -269,29 +207,14 @@ void sched_clock_tick(void)
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now = sched_clock();
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__raw_spin_lock(&scd->lock);
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__update_sched_clock(scd, now, NULL);
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__update_sched_clock(scd, now);
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/*
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* update tick_gtod after __update_sched_clock() because that will
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* already observe 1 new jiffy; adding a new tick_gtod to that would
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* increase the clock 2 jiffies.
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*/
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delta_gtod = now_gtod - scd->tick_gtod;
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delta_raw = now - scd->tick_raw;
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if ((long)delta_raw > 0) {
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mult = delta_gtod << MULTI_SHIFT;
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do_div(mult, delta_raw);
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scd->multi = mult;
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if (scd->multi > MAX_MULTI)
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scd->multi = MAX_MULTI;
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else if (scd->multi < MIN_MULTI)
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scd->multi = MIN_MULTI;
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} else
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scd->multi = 1 << MULTI_SHIFT;
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scd->tick_raw = now;
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scd->tick_gtod = now_gtod;
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scd->tick_jiffies = now_jiffies;
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__raw_spin_unlock(&scd->lock);
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}
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@ -310,7 +233,6 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
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void sched_clock_idle_wakeup_event(u64 delta_ns)
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{
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struct sched_clock_data *scd = this_scd();
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u64 now = sched_clock();
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/*
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* Override the previous timestamp and ignore all
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@ -319,15 +241,28 @@ void sched_clock_idle_wakeup_event(u64 delta_ns)
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* rq clock:
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*/
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__raw_spin_lock(&scd->lock);
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scd->prev_raw = now;
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scd->clock += delta_ns;
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scd->multi = 1 << MULTI_SHIFT;
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__raw_spin_unlock(&scd->lock);
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touch_softlockup_watchdog();
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}
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EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
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#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
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void sched_clock_init(void)
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{
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sched_clock_running = 1;
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}
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u64 sched_clock_cpu(int cpu)
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{
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if (unlikely(!sched_clock_running))
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return 0;
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return sched_clock();
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}
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#endif
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unsigned long long cpu_clock(int cpu)
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@ -289,7 +289,6 @@ void tick_nohz_stop_sched_tick(int inidle)
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ts->tick_stopped = 1;
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ts->idle_jiffies = last_jiffies;
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rcu_enter_nohz();
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sched_clock_tick_stop(cpu);
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}
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/*
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@ -392,7 +391,6 @@ void tick_nohz_restart_sched_tick(void)
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select_nohz_load_balancer(0);
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now = ktime_get();
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tick_do_update_jiffies64(now);
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sched_clock_tick_start(cpu);
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cpu_clear(cpu, nohz_cpu_mask);
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/*
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