tree dde8d56d000c7885c43df0e61f72f4a75d5759fe
parent ee974e01e5ef2914036f08c8e41d1a3fa8bfc9d9
author John Stultz <johnstul@us.ibm.com> 1219275448 -0700
committer Ingo Molnar <mingo@elte.hu> 1219305023 +0200

clocksource: keep track of original clocksource frequency

The clocksource frequency is represented by
clocksource->mult/2^(clocksource->shift).  Currently, when NTP makes
adjustments to the clock frequency, they are made directly to the mult
value.

This has the drawback that once changed, we cannot know what the orignal
mult value was, or how much adjustment has been applied.

This property causes problems in calculating proper ntp intervals when
switching back and forth between clocksources.

This patch separates the current mult value into a mult and mult_orig
pair.  The mult_orig value stays constant, while the ntp clocksource
adjustments are done only to the mult value.

This allows for correct ntp interval calculation and additionally lays the
groundwork for a new notion of time, what I'm calling the monotonic-raw
time, which is introduced in a following patch.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>