From 7d84c1ebf9ddafca27b481e6da7d24a023dacaa2 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 15 Apr 2022 21:20:02 +0200
Subject: x86/aperfmperf: Replace aperfmperf_get_khz()

The frequency invariance infrastructure provides the APERF/MPERF samples
already. Utilize them for the cpu frequency display in /proc/cpuinfo.

The sample is considered valid for 20ms. So for idle or isolated NOHZ full
CPUs the function returns 0, which is matching the previous behaviour.

This gets rid of the mass IPIs and a delay of 20ms for stabilizing observed
by Eric when reading /proc/cpuinfo.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20220415161206.875029458@linutronix.de
---
 fs/proc/cpuinfo.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

(limited to 'fs/proc')

diff --git a/fs/proc/cpuinfo.c b/fs/proc/cpuinfo.c
index 419760fd77bd..f38bda5b83ec 100644
--- a/fs/proc/cpuinfo.c
+++ b/fs/proc/cpuinfo.c
@@ -5,14 +5,10 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 
-__weak void arch_freq_prepare_all(void)
-{
-}
-
 extern const struct seq_operations cpuinfo_op;
+
 static int cpuinfo_open(struct inode *inode, struct file *file)
 {
-	arch_freq_prepare_all();
 	return seq_open(file, &cpuinfo_op);
 }
 
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