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timers: Add CLOCK_BOOTTIME hrtimer base 

CLOCK_MONOTONIC stops while the system is in suspend. This is because
to applications system suspend is invisible. However, there is a
growing set of applications that are wanting to be suspend-aware,
but do not want to deal with the complications of CLOCK_REALTIME
(which might jump around if settimeofday is called).

For these applications, I propose a new clockid: CLOCK_BOOTTIME.
CLOCK_BOOTTIME is idential to CLOCK_MONOTONIC, except it also
includes any time spent in suspend.

This patch add hrtimer base for CLOCK_BOOTTIME, using
get_monotonic_boottime/ktime_get_boottime, to allow
in kernel users to set timers against.

CC: Jamie Lokier <jamie@shareable.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alexander Shishkin <virtuoso@slind.org>
CC: Arve Hjønnevåg <arve@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
John Stultz 2011-02-15 10:45:16 -08:00
parent 314ac37150
commit 70a08cca12
3 changed files with 14 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/hrtimer.h
View File

@ -151,6 +151,7 @@ struct hrtimer_clock_base {
enum hrtimer_base_type {
HRTIMER_BASE_REALTIME,
HRTIMER_BASE_MONOTONIC,
HRTIMER_BASE_BOOTTIME,
HRTIMER_MAX_CLOCK_BASES,
};

1
include/linux/time.h
View File

@ -293,6 +293,7 @@ struct itimerval {
#define CLOCK_MONOTONIC_RAW 4
#define CLOCK_REALTIME_COARSE 5
#define CLOCK_MONOTONIC_COARSE 6
#define CLOCK_BOOTTIME 7
/*
* The IDs of various hardware clocks:

16
kernel/hrtimer.c
View File

@ -73,6 +73,11 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
.get_time = &ktime_get,
.resolution = KTIME_LOW_RES,
},
{
.index = CLOCK_BOOTTIME,
.get_time = &ktime_get_boottime,
.resolution = KTIME_LOW_RES,
},
}
};
@ -90,16 +95,17 @@ static inline int hrtimer_clockid_to_base(clockid_t clock_id)
*/
static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
{
ktime_t xtim, tomono;
ktime_t xtim, mono, boot;
struct timespec xts, tom, slp;
get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp);
xtim = timespec_to_ktime(xts);
tomono = timespec_to_ktime(tom);
mono = ktime_add(xtim, timespec_to_ktime(tom));
boot = ktime_add(mono, timespec_to_ktime(slp));
base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time =
ktime_add(xtim, tomono);
base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
}
/*
@ -727,6 +733,7 @@ static int hrtimer_switch_to_hres(void)
base->hres_active = 1;
base->clock_base[HRTIMER_BASE_REALTIME].resolution = KTIME_HIGH_RES;
base->clock_base[HRTIMER_BASE_MONOTONIC].resolution = KTIME_HIGH_RES;
base->clock_base[HRTIMER_BASE_BOOTTIME].resolution = KTIME_HIGH_RES;
tick_setup_sched_timer();
@ -1719,6 +1726,7 @@ void __init hrtimers_init(void)
{
hrtimer_clock_to_base_table[CLOCK_REALTIME] = HRTIMER_BASE_REALTIME;
hrtimer_clock_to_base_table[CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC;
hrtimer_clock_to_base_table[CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME;
hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
(void *)(long)smp_processor_id());