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pvclock: detect watchdog reset at pvclock read

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Implement reset of kernel watchdogs at pvclock read time. This avoids
adding special code to every watchdog.

This is possible for watchdogs which measure time based on sched_clock() or
ktime_get() variants.

Suggested by Don Zickus.

Acked-by: Don Zickus <dzickus@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This commit is contained in:
Marcelo Tosatti 2013-10-11 21:39:25 -03:00 committed by Gleb Natapov
parent 01b71917b5
commit d63285e94a
3 changed files with 15 additions and 0 deletions
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2
arch/x86/include/asm/pvclock.h
View File

@ -14,6 +14,8 @@ void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
struct timespec *ts);
void pvclock_resume(void);
void pvclock_touch_watchdogs(void);
/*
* Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
* yielding a 64-bit result.

1
arch/x86/kernel/kvmclock.c
View File

@ -139,6 +139,7 @@ bool kvm_check_and_clear_guest_paused(void)
src = &hv_clock[cpu].pvti;
if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) {
src->flags &= ~PVCLOCK_GUEST_STOPPED;
pvclock_touch_watchdogs();
ret = true;
}

12
arch/x86/kernel/pvclock.c
View File

@ -43,6 +43,13 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src)
return pv_tsc_khz;
}
void pvclock_touch_watchdogs(void)
{
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
rcu_cpu_stall_reset();
}
static atomic64_t last_value = ATOMIC64_INIT(0);
void pvclock_resume(void)
@ -74,6 +81,11 @@ cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
version = __pvclock_read_cycles(src, &ret, &flags);
} while ((src->version & 1) || version != src->version);
if (unlikely((flags & PVCLOCK_GUEST_STOPPED) != 0)) {
src->flags &= ~PVCLOCK_GUEST_STOPPED;
pvclock_touch_watchdogs();
}
if ((valid_flags & PVCLOCK_TSC_STABLE_BIT) &&
(flags & PVCLOCK_TSC_STABLE_BIT))
return ret;