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| author | Paul E. McKenney <paulmck@kernel.org> | 2021-05-27 12:01:20 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2021-06-22 16:53:16 +0200 |
| commit | 7560c02bdffb7c52d1457fa551b9e745d4b9e754 (patch) | |
| tree | 8abaac4ea4ec95b5ecd4ea3768b3dd722a926218 /arch/x86/kernel/tsc.c | |
| parent | db3a34e17433de2390eb80d436970edcebd0ca3e (diff) | |
| download | linux-7560c02bdffb7c52d1457fa551b9e745d4b9e754.tar.gz | |
clocksource: Check per-CPU clock synchronization when marked unstable
Some sorts of per-CPU clock sources have a history of going out of synchronization with each other. However, this problem has purportedy been solved in the past ten years. Except that it is all too possible that the problem has instead simply been made less likely, which might mean that some of the occasional "Marking clocksource 'tsc' as unstable" messages might be due to desynchronization. How would anyone know? Therefore apply CPU-to-CPU synchronization checking to newly unstable clocksource that are marked with the new CLOCK_SOURCE_VERIFY_PERCPU flag. Lists of desynchronized CPUs are printed, with the caveat that if it is the reporting CPU that is itself desynchronized, it will appear that all the other clocks are wrong. Just like in real life. Reported-by: Chris Mason <clm@fb.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Feng Tang <feng.tang@intel.com> Link: https://lore.kernel.org/r/20210527190124.440372-2-paulmck@kernel.org
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 57ec01192180..6eb1b097e97e 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1152,7 +1152,8 @@ static struct clocksource clocksource_tsc = { .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_VALID_FOR_HRES | - CLOCK_SOURCE_MUST_VERIFY, + CLOCK_SOURCE_MUST_VERIFY | + CLOCK_SOURCE_VERIFY_PERCPU, .vdso_clock_mode = VDSO_CLOCKMODE_TSC, .enable = tsc_cs_enable, .resume = tsc_resume, |