[PATCH 4/9] x86/tsc,sched/clock,clocksource: Use clocksource watchdog to provide stable sync points

Currently we keep sched_clock_tick() active for stable TSC in order to keep the per-cpu state semi up-to-date. The (obvious) problem is that by the time we detect TSC is borked, our per-cpu state is also borked. So hook into the clocksource watchdog and call a method after we've found it to still

[PATCH 4/9] x86/tsc,sched/clock,clocksource: Use clocksource watchdog to provide stable sync points

Currently we keep sched_clock_tick() active for stable TSC in order to keep the per-cpu state semi up-to-date. The (obvious) problem is that by the time we detect TSC is borked, our per-cpu state is also borked. So hook into the clocksource watchdog and call a method after we've found it to still