timekeeping: Indicate that clock was set in the pvclock gtod notifier
authorDavid Vrabel <david.vrabel@citrix.com>
Thu, 27 Jun 2013 10:35:46 +0000 (11:35 +0100)
committerThomas Gleixner <tglx@linutronix.de>
Fri, 28 Jun 2013 21:15:06 +0000 (23:15 +0200)
commit780427f0e113b4c77dfff4d258c05a902cdb0eb9
tree778bc50cbd83b67bdd6ae580a192c4c65e9711bd
parent04397fe94ad65289884b9862b6a0c722ececaadf
timekeeping: Indicate that clock was set in the pvclock gtod notifier

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>
include/linux/pvclock_gtod.h
kernel/time/timekeeping.c