780427f0e1
If the clock was set (stepped), set the action parameter to functions in the pvclock gtod notifier chain to non-zero. This allows the callee to only do work if the clock was stepped. This will be used on Xen as the synchronization of the Xen wallclock to the control domain's (dom0) system time will be done with this notifier and updating on every timer tick is unnecessary and too expensive. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-4-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
17 lines
509 B
C
17 lines
509 B
C
#ifndef _PVCLOCK_GTOD_H
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#define _PVCLOCK_GTOD_H
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#include <linux/notifier.h>
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/*
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* The pvclock gtod notifier is called when the system time is updated
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* and is used to keep guest time synchronized with host time.
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*
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* The 'action' parameter in the notifier function is false (0), or
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* true (non-zero) if system time was stepped.
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*/
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extern int pvclock_gtod_register_notifier(struct notifier_block *nb);
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extern int pvclock_gtod_unregister_notifier(struct notifier_block *nb);
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#endif /* _PVCLOCK_GTOD_H */
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