diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/clock.c | 41 | ||||
| -rw-r--r-- | kernel/sched/debug.c | 2 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 2 | ||||
| -rw-r--r-- | kernel/trace/ring_buffer.c | 2 |
4 files changed, 37 insertions, 10 deletions
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index 59371549ddf0..c9b34c4e3ecc 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -58,6 +58,7 @@ #include <linux/percpu.h> #include <linux/ktime.h> #include <linux/sched.h> +#include <linux/static_key.h> /* * Scheduler clock - returns current time in nanosec units. @@ -74,7 +75,27 @@ EXPORT_SYMBOL_GPL(sched_clock); __read_mostly int sched_clock_running; #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK -__read_mostly int sched_clock_stable; +static struct static_key __sched_clock_stable = STATIC_KEY_INIT; + +int sched_clock_stable(void) +{ + if (static_key_false(&__sched_clock_stable)) + return false; + return true; +} + +void set_sched_clock_stable(void) +{ + if (!sched_clock_stable()) + static_key_slow_dec(&__sched_clock_stable); +} + +void clear_sched_clock_stable(void) +{ + /* XXX worry about clock continuity */ + if (sched_clock_stable()) + static_key_slow_inc(&__sched_clock_stable); +} struct sched_clock_data { u64 tick_raw; @@ -234,7 +255,7 @@ u64 sched_clock_cpu(int cpu) struct sched_clock_data *scd; u64 clock; - if (sched_clock_stable) + if (sched_clock_stable()) return sched_clock(); if (unlikely(!sched_clock_running)) @@ -257,7 +278,7 @@ void sched_clock_tick(void) struct sched_clock_data *scd; u64 now, now_gtod; - if (sched_clock_stable) + if (sched_clock_stable()) return; if (unlikely(!sched_clock_running)) @@ -308,7 +329,10 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); */ u64 cpu_clock(int cpu) { - return sched_clock_cpu(cpu); + if (static_key_false(&__sched_clock_stable)) + return sched_clock_cpu(cpu); + + return sched_clock(); } /* @@ -320,7 +344,10 @@ u64 cpu_clock(int cpu) */ u64 local_clock(void) { - return sched_clock_cpu(raw_smp_processor_id()); + if (static_key_false(&__sched_clock_stable)) + return sched_clock_cpu(raw_smp_processor_id()); + + return sched_clock(); } #else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */ @@ -340,12 +367,12 @@ u64 sched_clock_cpu(int cpu) u64 cpu_clock(int cpu) { - return sched_clock_cpu(cpu); + return sched_clock(); } u64 local_clock(void) { - return sched_clock_cpu(0); + return sched_clock(); } #endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */ diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 374fe04a5e6e..dd52e7ffb10e 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -371,7 +371,7 @@ static void sched_debug_header(struct seq_file *m) PN(cpu_clk); P(jiffies); #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK - P(sched_clock_stable); + P(sched_clock_stable()); #endif #undef PN #undef P diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index ea20f7d1ac2c..c833249ab0fb 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -177,7 +177,7 @@ static bool can_stop_full_tick(void) * TODO: kick full dynticks CPUs when * sched_clock_stable is set. */ - if (!sched_clock_stable) { + if (!sched_clock_stable()) { trace_tick_stop(0, "unstable sched clock\n"); /* * Don't allow the user to think they can get diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index cc2f66f68dc5..294b8a271a04 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2558,7 +2558,7 @@ rb_reserve_next_event(struct ring_buffer *buffer, if (unlikely(test_time_stamp(delta))) { int local_clock_stable = 1; #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK - local_clock_stable = sched_clock_stable; + local_clock_stable = sched_clock_stable(); #endif WARN_ONCE(delta > (1ULL << 59), KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n%s", |