diff options
| -rw-r--r-- | include/linux/tick.h | 4 | ||||
| -rw-r--r-- | kernel/time/Kconfig | 1 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 51 |
3 files changed, 56 insertions, 0 deletions
diff --git a/include/linux/tick.h b/include/linux/tick.h index b4e3b0c9639..c2dcfb18f65 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -159,8 +159,12 @@ static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; } #ifdef CONFIG_NO_HZ_FULL extern int tick_nohz_full_cpu(int cpu); +extern void tick_nohz_full_kick(void); +extern void tick_nohz_full_kick_all(void); #else static inline int tick_nohz_full_cpu(int cpu) { return 0; } +static inline void tick_nohz_full_kick(void) { } +static inline void tick_nohz_full_kick_all(void) { } #endif diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 358d601a4fe..fbb4c7eb92a 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -111,6 +111,7 @@ config NO_HZ_FULL select RCU_USER_QS select RCU_NOCB_CPU select CONTEXT_TRACKING_FORCE + select IRQ_WORK help Adaptively try to shutdown the tick whenever possible, even when the CPU is running tasks. Typically this requires running a single diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 369b5769fc9..2bcad5b904d 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -147,6 +147,57 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs) static cpumask_var_t nohz_full_mask; bool have_nohz_full_mask; +/* + * Re-evaluate the need for the tick on the current CPU + * and restart it if necessary. + */ +static void tick_nohz_full_check(void) +{ + /* + * STUB for now, will be filled with the full tick stop/restart + * infrastructure patches + */ +} + +static void nohz_full_kick_work_func(struct irq_work *work) +{ + tick_nohz_full_check(); +} + +static DEFINE_PER_CPU(struct irq_work, nohz_full_kick_work) = { + .func = nohz_full_kick_work_func, +}; + +/* + * Kick the current CPU if it's full dynticks in order to force it to + * re-evaluate its dependency on the tick and restart it if necessary. + */ +void tick_nohz_full_kick(void) +{ + if (tick_nohz_full_cpu(smp_processor_id())) + irq_work_queue(&__get_cpu_var(nohz_full_kick_work)); +} + +static void nohz_full_kick_ipi(void *info) +{ + tick_nohz_full_check(); +} + +/* + * Kick all full dynticks CPUs in order to force these to re-evaluate + * their dependency on the tick and restart it if necessary. + */ +void tick_nohz_full_kick_all(void) +{ + if (!have_nohz_full_mask) + return; + + preempt_disable(); + smp_call_function_many(nohz_full_mask, + nohz_full_kick_ipi, NULL, false); + preempt_enable(); +} + int tick_nohz_full_cpu(int cpu) { if (!have_nohz_full_mask) |