Commit ab8177bc authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

hrtimers: Avoid touching inactive timer bases 



Instead of iterating over all possible timer bases avoid it by marking
the active bases in the cpu base.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarPeter Zijlstra <peterz@infradead.org>
parent f24444b0

include/linux/hrtimer.h

+5 −2
Original line number Diff line number Diff line
@@ -143,7 +143,8 @@ struct hrtimer_sleeper { 
 */

struct hrtimer_clock_base {

	struct hrtimer_cpu_base	*cpu_base;

	clockid_t		index;

	int			index;

	clockid_t		clockid;

	struct timerqueue_head	active;

	ktime_t			resolution;

	ktime_t			(*get_time)(void);
@@ -162,7 +163,7 @@ enum hrtimer_base_type { 
 * struct hrtimer_cpu_base - the per cpu clock bases

 * @lock:		lock protecting the base and associated clock bases

 *			and timers

 * @clock_base:		array of clock bases for this cpu

 * @active_bases:	Bitfield to mark bases with active timers

 * @expires_next:	absolute time of the next event which was scheduled

 *			via clock_set_next_event()

 * @hres_active:	State of high resolution mode
@@ -171,9 +172,11 @@ enum hrtimer_base_type { 
 * @nr_retries:		Total number of hrtimer interrupt retries

 * @nr_hangs:		Total number of hrtimer interrupt hangs

 * @max_hang_time:	Maximum time spent in hrtimer_interrupt

 * @clock_base:		array of clock bases for this cpu

 */

struct hrtimer_cpu_base {

	raw_spinlock_t			lock;

	unsigned long			active_bases;

#ifdef CONFIG_HIGH_RES_TIMERS

	ktime_t				expires_next;

	int				hres_active;

include/linux/thread_info.h

+1 −1
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ struct restart_block { 
		} futex;

		/* For nanosleep */

		struct {

			clockid_t index;

			clockid_t clockid;

			struct timespec __user *rmtp;

#ifdef CONFIG_COMPAT

			struct compat_timespec __user *compat_rmtp;

kernel/hrtimer.c

+18 −11
Original line number Diff line number Diff line
@@ -64,17 +64,20 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = 
	.clock_base =

	{

		{

			.index = CLOCK_REALTIME,

			.index = HRTIMER_BASE_REALTIME,

			.clockid = CLOCK_REALTIME,

			.get_time = &ktime_get_real,

			.resolution = KTIME_LOW_RES,

		},

		{

			.index = CLOCK_MONOTONIC,

			.index = HRTIMER_BASE_MONOTONIC,

			.clockid = CLOCK_MONOTONIC,

			.get_time = &ktime_get,

			.resolution = KTIME_LOW_RES,

		},

		{

			.index = CLOCK_BOOTTIME,

			.index = HRTIMER_BASE_BOOTTIME,

			.clockid = CLOCK_BOOTTIME,

			.get_time = &ktime_get_boottime,

			.resolution = KTIME_LOW_RES,

		},
@@ -196,7 +199,7 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base, 
	struct hrtimer_cpu_base *new_cpu_base;

	int this_cpu = smp_processor_id();

	int cpu = hrtimer_get_target(this_cpu, pinned);

	int basenum = hrtimer_clockid_to_base(base->index);

	int basenum = base->index;



again:

	new_cpu_base = &per_cpu(hrtimer_bases, cpu);
@@ -857,6 +860,7 @@ static int enqueue_hrtimer(struct hrtimer *timer, 
	debug_activate(timer);



	timerqueue_add(&base->active, &timer->node);

	base->cpu_base->active_bases |= 1 << base->index;



	/*

	 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
@@ -898,6 +902,8 @@ static void __remove_hrtimer(struct hrtimer *timer, 
#endif

	}

	timerqueue_del(&base->active, &timer->node);

	if (!timerqueue_getnext(&base->active))

		base->cpu_base->active_bases &= ~(1 << base->index);

out:

	timer->state = newstate;

}
@@ -1235,7 +1241,6 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now) 
void hrtimer_interrupt(struct clock_event_device *dev)

{

	struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);

	struct hrtimer_clock_base *base;

	ktime_t expires_next, now, entry_time, delta;

	int i, retries = 0;
@@ -1257,12 +1262,15 @@ void hrtimer_interrupt(struct clock_event_device *dev) 
	 */

	cpu_base->expires_next.tv64 = KTIME_MAX;



	base = cpu_base->clock_base;



	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {

		ktime_t basenow;

		struct hrtimer_clock_base *base;

		struct timerqueue_node *node;

		ktime_t basenow;



		if (!(cpu_base->active_bases & (1 << i)))

			continue;



		base = cpu_base->clock_base + i;

		basenow = ktime_add(now, base->offset);



		while ((node = timerqueue_getnext(&base->active))) {
@@ -1295,7 +1303,6 @@ void hrtimer_interrupt(struct clock_event_device *dev) 


			__run_hrtimer(timer, &basenow);

		}

		base++;

	}



	/*
@@ -1526,7 +1533,7 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart) 
	struct timespec __user  *rmtp;

	int ret = 0;



	hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,

	hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,

				HRTIMER_MODE_ABS);

	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
@@ -1578,7 +1585,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp, 


	restart = &current_thread_info()->restart_block;

	restart->fn = hrtimer_nanosleep_restart;

	restart->nanosleep.index = t.timer.base->index;

	restart->nanosleep.clockid = t.timer.base->clockid;

	restart->nanosleep.rmtp = rmtp;

	restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);

kernel/posix-cpu-timers.c

+2 −2
Original line number Diff line number Diff line
@@ -1514,7 +1514,7 @@ static int posix_cpu_nsleep(const clockid_t which_clock, int flags, 
			return -EFAULT;



		restart_block->fn = posix_cpu_nsleep_restart;

		restart_block->nanosleep.index = which_clock;

		restart_block->nanosleep.clockid = which_clock;

		restart_block->nanosleep.rmtp = rmtp;

		restart_block->nanosleep.expires = timespec_to_ns(rqtp);

	}
@@ -1523,7 +1523,7 @@ static int posix_cpu_nsleep(const clockid_t which_clock, int flags, 


static long posix_cpu_nsleep_restart(struct restart_block *restart_block)

{

	clockid_t which_clock = restart_block->nanosleep.index;

	clockid_t which_clock = restart_block->nanosleep.clockid;

	struct timespec t;

	struct itimerspec it;

	int error;

kernel/posix-timers.c

+1 −1
Original line number Diff line number Diff line
@@ -1056,7 +1056,7 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags, 
 */

long clock_nanosleep_restart(struct restart_block *restart_block)

{

	clockid_t which_clock = restart_block->nanosleep.index;

	clockid_t which_clock = restart_block->nanosleep.clockid;

	struct k_clock *kc = clockid_to_kclock(which_clock);



	if (WARN_ON_ONCE(!kc || !kc->nsleep_restart))