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| author | Paul E. McKenney <paulmck@kernel.org> | 2020-09-04 01:23:29 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-11-07 03:59:11 +0300 |
| commit | 3fcd6a230fa7d03bffcb831a81b40435c146c12b (patch) | |
| tree | bc576b40954c9deb95bf32151cb4535fe889297f /include/linux/rcutiny.h | |
| parent | f4deaf90212c18d4b6d0687f0cba4c22d90b3391 (diff) | |
| download | linux-3fcd6a230fa7d03bffcb831a81b40435c146c12b.tar.xz | |
x86/cpu: Avoid cpuinfo-induced IPIing of idle CPUs
Currently, accessing /proc/cpuinfo sends IPIs to idle CPUs in order to
learn their clock frequency. Which is a bit strange, given that waking
them from idle likely significantly changes their clock frequency.
This commit therefore avoids sending /proc/cpuinfo-induced IPIs to
idle CPUs.
[ paulmck: Also check for idle in arch_freq_prepare_all(). ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <x86@kernel.org>
Diffstat (limited to 'include/linux/rcutiny.h')
| -rw-r--r-- | include/linux/rcutiny.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 7c1ecdb356d8..2a97334eb786 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -89,6 +89,8 @@ static inline void rcu_irq_enter_irqson(void) { } static inline void rcu_irq_exit(void) { } static inline void rcu_irq_exit_preempt(void) { } static inline void rcu_irq_exit_check_preempt(void) { } +#define rcu_is_idle_cpu(cpu) \ + (is_idle_task(current) && !in_nmi() && !in_irq() && !in_serving_softirq()) static inline void exit_rcu(void) { } static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t) { |