[PATCH] x86/aperfmperf: use time_is_before_jiffies(a + b) to replace "jiffies - a > b"

From: Yu Zhe
Date: Tue Jul 26 2022 - 23:15:16 EST


time_is_before_jiffies deals with timer wrapping correctly.

Signed-off-by: Yu Zhe <yuzhe@xxxxxxxxxxxx>
---
arch/x86/kernel/cpu/aperfmperf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c
index 1f60a2b27936..22e0bac3fffe 100644
--- a/arch/x86/kernel/cpu/aperfmperf.c
+++ b/arch/x86/kernel/cpu/aperfmperf.c
@@ -423,7 +423,7 @@ unsigned int arch_freq_get_on_cpu(int cpu)
* Bail on invalid count and when the last update was too long ago,
* which covers idle and NOHZ full CPUs.
*/
- if (!mcnt || (jiffies - last) > MAX_SAMPLE_AGE)
+ if (!mcnt || time_is_before_jiffies(last + MAX_SAMPLE_AGE))
goto fallback;

return div64_u64((cpu_khz * acnt), mcnt);
--
2.11.0