Commit 70a08cca authored by John Stultz's avatar John Stultz
Browse files

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: default avatarJohn Stultz <john.stultz@linaro.org>
parent 314ac371

include/linux/hrtimer.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

};

include/linux/time.h

+1 −0
Original line number Diff line number Diff line
@@ -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:

kernel/hrtimer.c

+12 −4
Original line number Diff line number Diff line
@@ -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());

CRA Git | Maintained and supported by SUSTech CRA and CCSE