diff options
| 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 /include/linux/clocksource.h | |
| parent | db3a34e17433de2390eb80d436970edcebd0ca3e (diff) | |
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 'include/linux/clocksource.h')
| -rw-r--r-- | include/linux/clocksource.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index d6ab416ee2d2..7f83d51c0fd7 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -137,7 +137,7 @@ struct clocksource { #define CLOCK_SOURCE_UNSTABLE 0x40 #define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80 #define CLOCK_SOURCE_RESELECT 0x100 - +#define CLOCK_SOURCE_VERIFY_PERCPU 0x200 /* simplify initialization of mask field */ #define CLOCKSOURCE_MASK(bits) GENMASK_ULL((bits) - 1, 0) |