#ifndef _PVCLOCK_GTOD_H#define _PVCLOCK_GTOD_H#include <linux/notifier.h>/* * The pvclock gtod notifier is called when the system time is updated * and is used to keep guest time synchronized with host time. * * The 'action' parameter in the notifier function is false (0), or * true (non-zero) if system time was stepped. */externintpvclock_gtod_register_notifier(structnotifier_block*nb);externintpvclock_gtod_unregister_notifier(structnotifier_block*nb);#endif /* _PVCLOCK_GTOD_H */