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. Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com> Index: kvm/arch/x86/kernel/kvmclock.c =================================================================== --- kvm.orig/arch/x86/kernel/kvmclock.c +++ kvm/arch/x86/kernel/kvmclock.c @@ -139,6 +139,7 @@ bool kvm_check_and_clear_guest_paused(vo src = &hv_clock[cpu].pvti; if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) { src->flags &= ~PVCLOCK_GUEST_STOPPED; + pvclock_touch_watchdogs(); ret = true; } Index: kvm/arch/x86/kernel/pvclock.c =================================================================== --- kvm.orig/arch/x86/kernel/pvclock.c +++ kvm/arch/x86/kernel/pvclock.c @@ -21,6 +21,7 @@ #include <linux/sched.h> #include <linux/gfp.h> #include <linux/bootmem.h> +#include <linux/hung_task.h> #include <asm/fixmap.h> #include <asm/pvclock.h> @@ -43,6 +44,14 @@ unsigned long pvclock_tsc_khz(struct pvc return pv_tsc_khz; } +void pvclock_touch_watchdogs(void) +{ + touch_softlockup_watchdog_sync(); + clocksource_touch_watchdog(); + rcu_cpu_stall_reset(); + reset_hung_task_detector(); +} + static atomic64_t last_value = ATOMIC64_INIT(0); void pvclock_resume(void) @@ -74,6 +83,11 @@ cycle_t pvclock_clocksource_read(struct 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; Index: kvm/arch/x86/include/asm/pvclock.h =================================================================== --- kvm.orig/arch/x86/include/asm/pvclock.h +++ kvm/arch/x86/include/asm/pvclock.h @@ -14,6 +14,8 @@ void pvclock_read_wallclock(struct pvclo 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. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html