hrtimers: Reorder clock bases
The ordering of the clock bases is historical due to the
CLOCK_REALTIME and CLOCK_MONOTONIC constants. Now the hrtimer bases
have their own enumeration due to the gap between CLOCK_MONOTONIC and
CLOCK_BOOTTIME. So we can be more clever as most timers end up on the
CLOCK_MONOTONIC base due to the virtue of POSIX declaring that
relative CLOCK_REALTIME timers are not affected by time changes. In
desktop environments this is slowly changing as applications switch to
absolute timers, but I've observed empty CLOCK_REALTIME bases often
enough. There is no performance penalty or overhead when
CLOCK_REALTIME timers are active, but in case they are not we don't
skip over a full cache line.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 771c958..51932e5 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -153,8 +153,8 @@
};
enum hrtimer_base_type {
- HRTIMER_BASE_REALTIME,
HRTIMER_BASE_MONOTONIC,
+ HRTIMER_BASE_REALTIME,
HRTIMER_BASE_BOOTTIME,
HRTIMER_MAX_CLOCK_BASES,
};