Merge tag 'timers-nohz-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timers/nohz updates from Ingo Molnar:

 - Micro-optimize tick_nohz_full_cpu()

 - Optimize idle exit tick restarts to be less eager

 - Optimize tick_nohz_dep_set_task() to only wake up a single CPU.
   This reduces IPIs and interruptions on nohz_full CPUs.

 - Optimize tick_nohz_dep_set_signal() in a similar fashion.

 - Skip IPIs in tick_nohz_kick_task() when trying to kick a
   non-running task.

 - Micro-optimize tick_nohz_task_switch() IRQ flags handling to
   reduce context switching costs.

 - Misc cleanups and fixes

* tag 'timers-nohz-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Add myself as context tracking maintainer
  tick/nohz: Call tick_nohz_task_switch() with interrupts disabled
  tick/nohz: Kick only _queued_ task whose tick dependency is updated
  tick/nohz: Change signal tick dependency to wake up CPUs of member tasks
  tick/nohz: Only wake up a single target cpu when kicking a task
  tick/nohz: Update nohz_full Kconfig help
  tick/nohz: Update idle_exittime on actual idle exit
  tick/nohz: Remove superflous check for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
  tick/nohz: Conditionally restart tick on idle exit
  tick/nohz: Evaluate the CPU expression after the static key
This commit is contained in:
Linus Torvalds
2021-06-28 12:22:06 -07:00
7 changed files with 126 additions and 61 deletions

View File

@@ -186,13 +186,17 @@ static inline bool tick_nohz_full_enabled(void)
return tick_nohz_full_running;
}
static inline bool tick_nohz_full_cpu(int cpu)
{
if (!tick_nohz_full_enabled())
return false;
return cpumask_test_cpu(cpu, tick_nohz_full_mask);
}
/*
* Check if a CPU is part of the nohz_full subset. Arrange for evaluating
* the cpu expression (typically smp_processor_id()) _after_ the static
* key.
*/
#define tick_nohz_full_cpu(_cpu) ({ \
bool __ret = false; \
if (tick_nohz_full_enabled()) \
__ret = cpumask_test_cpu((_cpu), tick_nohz_full_mask); \
__ret; \
})
static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask)
{
@@ -208,7 +212,7 @@ extern void tick_nohz_dep_set_task(struct task_struct *tsk,
enum tick_dep_bits bit);
extern void tick_nohz_dep_clear_task(struct task_struct *tsk,
enum tick_dep_bits bit);
extern void tick_nohz_dep_set_signal(struct signal_struct *signal,
extern void tick_nohz_dep_set_signal(struct task_struct *tsk,
enum tick_dep_bits bit);
extern void tick_nohz_dep_clear_signal(struct signal_struct *signal,
enum tick_dep_bits bit);
@@ -253,11 +257,11 @@ static inline void tick_dep_clear_task(struct task_struct *tsk,
if (tick_nohz_full_enabled())
tick_nohz_dep_clear_task(tsk, bit);
}
static inline void tick_dep_set_signal(struct signal_struct *signal,
static inline void tick_dep_set_signal(struct task_struct *tsk,
enum tick_dep_bits bit)
{
if (tick_nohz_full_enabled())
tick_nohz_dep_set_signal(signal, bit);
tick_nohz_dep_set_signal(tsk, bit);
}
static inline void tick_dep_clear_signal(struct signal_struct *signal,
enum tick_dep_bits bit)
@@ -285,7 +289,7 @@ static inline void tick_dep_set_task(struct task_struct *tsk,
enum tick_dep_bits bit) { }
static inline void tick_dep_clear_task(struct task_struct *tsk,
enum tick_dep_bits bit) { }
static inline void tick_dep_set_signal(struct signal_struct *signal,
static inline void tick_dep_set_signal(struct task_struct *tsk,
enum tick_dep_bits bit) { }
static inline void tick_dep_clear_signal(struct signal_struct *signal,
enum tick_dep_bits bit) { }