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authorPaul E. McKenney <paulmck@kernel.org>2020-09-04 01:23:29 +0300
committerPaul E. McKenney <paulmck@kernel.org>2020-11-07 03:59:11 +0300
commit3fcd6a230fa7d03bffcb831a81b40435c146c12b (patch)
treebc576b40954c9deb95bf32151cb4535fe889297f /include/linux/rcutree.h
parentf4deaf90212c18d4b6d0687f0cba4c22d90b3391 (diff)
downloadlinux-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/rcutree.h')
-rw-r--r--include/linux/rcutree.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 59eb5cd567d7..df578b73960f 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -50,6 +50,7 @@ void rcu_irq_exit(void);
void rcu_irq_exit_preempt(void);
void rcu_irq_enter_irqson(void);
void rcu_irq_exit_irqson(void);
+bool rcu_is_idle_cpu(int cpu);
#ifdef CONFIG_PROVE_RCU
void rcu_irq_exit_check_preempt(void);