x86/cpu: Avoid cpuinfo-induced IPIing of idle CPUs

Browse source

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>

...

This commit is contained in:

Paul E. McKenney 2020-09-03 15:23:29 -07:00

parent f4deaf9021

commit 3fcd6a230f

4 changed files with 17 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

6

arch/x86/kernel/cpu/aperfmperf.c

View file

2

include/linux/rcutiny.h

View file

1

include/linux/rcutree.h

View file

8

kernel/rcu/tree.c

View file