mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 19:46:40 +07:00
174cd4b1e5
Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
1771 lines
46 KiB
C
1771 lines
46 KiB
C
/*
|
|
* linux/kernel/hrtimer.c
|
|
*
|
|
* Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
|
|
* Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
|
|
* Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner
|
|
*
|
|
* High-resolution kernel timers
|
|
*
|
|
* In contrast to the low-resolution timeout API implemented in
|
|
* kernel/timer.c, hrtimers provide finer resolution and accuracy
|
|
* depending on system configuration and capabilities.
|
|
*
|
|
* These timers are currently used for:
|
|
* - itimers
|
|
* - POSIX timers
|
|
* - nanosleep
|
|
* - precise in-kernel timing
|
|
*
|
|
* Started by: Thomas Gleixner and Ingo Molnar
|
|
*
|
|
* Credits:
|
|
* based on kernel/timer.c
|
|
*
|
|
* Help, testing, suggestions, bugfixes, improvements were
|
|
* provided by:
|
|
*
|
|
* George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
|
|
* et. al.
|
|
*
|
|
* For licencing details see kernel-base/COPYING
|
|
*/
|
|
|
|
#include <linux/cpu.h>
|
|
#include <linux/export.h>
|
|
#include <linux/percpu.h>
|
|
#include <linux/hrtimer.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/kallsyms.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/tick.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/err.h>
|
|
#include <linux/debugobjects.h>
|
|
#include <linux/sched/signal.h>
|
|
#include <linux/sched/sysctl.h>
|
|
#include <linux/sched/rt.h>
|
|
#include <linux/sched/deadline.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/freezer.h>
|
|
|
|
#include <linux/uaccess.h>
|
|
|
|
#include <trace/events/timer.h>
|
|
|
|
#include "tick-internal.h"
|
|
|
|
/*
|
|
* The timer bases:
|
|
*
|
|
* There are more clockids than hrtimer bases. Thus, we index
|
|
* into the timer bases by the hrtimer_base_type enum. When trying
|
|
* to reach a base using a clockid, hrtimer_clockid_to_base()
|
|
* is used to convert from clockid to the proper hrtimer_base_type.
|
|
*/
|
|
DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
|
|
{
|
|
.lock = __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases.lock),
|
|
.seq = SEQCNT_ZERO(hrtimer_bases.seq),
|
|
.clock_base =
|
|
{
|
|
{
|
|
.index = HRTIMER_BASE_MONOTONIC,
|
|
.clockid = CLOCK_MONOTONIC,
|
|
.get_time = &ktime_get,
|
|
},
|
|
{
|
|
.index = HRTIMER_BASE_REALTIME,
|
|
.clockid = CLOCK_REALTIME,
|
|
.get_time = &ktime_get_real,
|
|
},
|
|
{
|
|
.index = HRTIMER_BASE_BOOTTIME,
|
|
.clockid = CLOCK_BOOTTIME,
|
|
.get_time = &ktime_get_boottime,
|
|
},
|
|
{
|
|
.index = HRTIMER_BASE_TAI,
|
|
.clockid = CLOCK_TAI,
|
|
.get_time = &ktime_get_clocktai,
|
|
},
|
|
}
|
|
};
|
|
|
|
static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
|
|
/* Make sure we catch unsupported clockids */
|
|
[0 ... MAX_CLOCKS - 1] = HRTIMER_MAX_CLOCK_BASES,
|
|
|
|
[CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
|
|
[CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
|
|
[CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
|
|
[CLOCK_TAI] = HRTIMER_BASE_TAI,
|
|
};
|
|
|
|
/*
|
|
* Functions and macros which are different for UP/SMP systems are kept in a
|
|
* single place
|
|
*/
|
|
#ifdef CONFIG_SMP
|
|
|
|
/*
|
|
* We require the migration_base for lock_hrtimer_base()/switch_hrtimer_base()
|
|
* such that hrtimer_callback_running() can unconditionally dereference
|
|
* timer->base->cpu_base
|
|
*/
|
|
static struct hrtimer_cpu_base migration_cpu_base = {
|
|
.seq = SEQCNT_ZERO(migration_cpu_base),
|
|
.clock_base = { { .cpu_base = &migration_cpu_base, }, },
|
|
};
|
|
|
|
#define migration_base migration_cpu_base.clock_base[0]
|
|
|
|
/*
|
|
* We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
|
|
* means that all timers which are tied to this base via timer->base are
|
|
* locked, and the base itself is locked too.
|
|
*
|
|
* So __run_timers/migrate_timers can safely modify all timers which could
|
|
* be found on the lists/queues.
|
|
*
|
|
* When the timer's base is locked, and the timer removed from list, it is
|
|
* possible to set timer->base = &migration_base and drop the lock: the timer
|
|
* remains locked.
|
|
*/
|
|
static
|
|
struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
|
|
unsigned long *flags)
|
|
{
|
|
struct hrtimer_clock_base *base;
|
|
|
|
for (;;) {
|
|
base = timer->base;
|
|
if (likely(base != &migration_base)) {
|
|
raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
|
|
if (likely(base == timer->base))
|
|
return base;
|
|
/* The timer has migrated to another CPU: */
|
|
raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
|
|
}
|
|
cpu_relax();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* With HIGHRES=y we do not migrate the timer when it is expiring
|
|
* before the next event on the target cpu because we cannot reprogram
|
|
* the target cpu hardware and we would cause it to fire late.
|
|
*
|
|
* Called with cpu_base->lock of target cpu held.
|
|
*/
|
|
static int
|
|
hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
|
|
{
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
ktime_t expires;
|
|
|
|
if (!new_base->cpu_base->hres_active)
|
|
return 0;
|
|
|
|
expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
|
|
return expires <= new_base->cpu_base->expires_next;
|
|
#else
|
|
return 0;
|
|
#endif
|
|
}
|
|
|
|
#ifdef CONFIG_NO_HZ_COMMON
|
|
static inline
|
|
struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
|
|
int pinned)
|
|
{
|
|
if (pinned || !base->migration_enabled)
|
|
return base;
|
|
return &per_cpu(hrtimer_bases, get_nohz_timer_target());
|
|
}
|
|
#else
|
|
static inline
|
|
struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
|
|
int pinned)
|
|
{
|
|
return base;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* We switch the timer base to a power-optimized selected CPU target,
|
|
* if:
|
|
* - NO_HZ_COMMON is enabled
|
|
* - timer migration is enabled
|
|
* - the timer callback is not running
|
|
* - the timer is not the first expiring timer on the new target
|
|
*
|
|
* If one of the above requirements is not fulfilled we move the timer
|
|
* to the current CPU or leave it on the previously assigned CPU if
|
|
* the timer callback is currently running.
|
|
*/
|
|
static inline struct hrtimer_clock_base *
|
|
switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
|
|
int pinned)
|
|
{
|
|
struct hrtimer_cpu_base *new_cpu_base, *this_cpu_base;
|
|
struct hrtimer_clock_base *new_base;
|
|
int basenum = base->index;
|
|
|
|
this_cpu_base = this_cpu_ptr(&hrtimer_bases);
|
|
new_cpu_base = get_target_base(this_cpu_base, pinned);
|
|
again:
|
|
new_base = &new_cpu_base->clock_base[basenum];
|
|
|
|
if (base != new_base) {
|
|
/*
|
|
* We are trying to move timer to new_base.
|
|
* However we can't change timer's base while it is running,
|
|
* so we keep it on the same CPU. No hassle vs. reprogramming
|
|
* the event source in the high resolution case. The softirq
|
|
* code will take care of this when the timer function has
|
|
* completed. There is no conflict as we hold the lock until
|
|
* the timer is enqueued.
|
|
*/
|
|
if (unlikely(hrtimer_callback_running(timer)))
|
|
return base;
|
|
|
|
/* See the comment in lock_hrtimer_base() */
|
|
timer->base = &migration_base;
|
|
raw_spin_unlock(&base->cpu_base->lock);
|
|
raw_spin_lock(&new_base->cpu_base->lock);
|
|
|
|
if (new_cpu_base != this_cpu_base &&
|
|
hrtimer_check_target(timer, new_base)) {
|
|
raw_spin_unlock(&new_base->cpu_base->lock);
|
|
raw_spin_lock(&base->cpu_base->lock);
|
|
new_cpu_base = this_cpu_base;
|
|
timer->base = base;
|
|
goto again;
|
|
}
|
|
timer->base = new_base;
|
|
} else {
|
|
if (new_cpu_base != this_cpu_base &&
|
|
hrtimer_check_target(timer, new_base)) {
|
|
new_cpu_base = this_cpu_base;
|
|
goto again;
|
|
}
|
|
}
|
|
return new_base;
|
|
}
|
|
|
|
#else /* CONFIG_SMP */
|
|
|
|
static inline struct hrtimer_clock_base *
|
|
lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
|
|
{
|
|
struct hrtimer_clock_base *base = timer->base;
|
|
|
|
raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
|
|
|
|
return base;
|
|
}
|
|
|
|
# define switch_hrtimer_base(t, b, p) (b)
|
|
|
|
#endif /* !CONFIG_SMP */
|
|
|
|
/*
|
|
* Functions for the union type storage format of ktime_t which are
|
|
* too large for inlining:
|
|
*/
|
|
#if BITS_PER_LONG < 64
|
|
/*
|
|
* Divide a ktime value by a nanosecond value
|
|
*/
|
|
s64 __ktime_divns(const ktime_t kt, s64 div)
|
|
{
|
|
int sft = 0;
|
|
s64 dclc;
|
|
u64 tmp;
|
|
|
|
dclc = ktime_to_ns(kt);
|
|
tmp = dclc < 0 ? -dclc : dclc;
|
|
|
|
/* Make sure the divisor is less than 2^32: */
|
|
while (div >> 32) {
|
|
sft++;
|
|
div >>= 1;
|
|
}
|
|
tmp >>= sft;
|
|
do_div(tmp, (unsigned long) div);
|
|
return dclc < 0 ? -tmp : tmp;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__ktime_divns);
|
|
#endif /* BITS_PER_LONG >= 64 */
|
|
|
|
/*
|
|
* Add two ktime values and do a safety check for overflow:
|
|
*/
|
|
ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
|
|
{
|
|
ktime_t res = ktime_add_unsafe(lhs, rhs);
|
|
|
|
/*
|
|
* We use KTIME_SEC_MAX here, the maximum timeout which we can
|
|
* return to user space in a timespec:
|
|
*/
|
|
if (res < 0 || res < lhs || res < rhs)
|
|
res = ktime_set(KTIME_SEC_MAX, 0);
|
|
|
|
return res;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(ktime_add_safe);
|
|
|
|
#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
|
|
|
|
static struct debug_obj_descr hrtimer_debug_descr;
|
|
|
|
static void *hrtimer_debug_hint(void *addr)
|
|
{
|
|
return ((struct hrtimer *) addr)->function;
|
|
}
|
|
|
|
/*
|
|
* fixup_init is called when:
|
|
* - an active object is initialized
|
|
*/
|
|
static bool hrtimer_fixup_init(void *addr, enum debug_obj_state state)
|
|
{
|
|
struct hrtimer *timer = addr;
|
|
|
|
switch (state) {
|
|
case ODEBUG_STATE_ACTIVE:
|
|
hrtimer_cancel(timer);
|
|
debug_object_init(timer, &hrtimer_debug_descr);
|
|
return true;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* fixup_activate is called when:
|
|
* - an active object is activated
|
|
* - an unknown non-static object is activated
|
|
*/
|
|
static bool hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
|
|
{
|
|
switch (state) {
|
|
case ODEBUG_STATE_ACTIVE:
|
|
WARN_ON(1);
|
|
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* fixup_free is called when:
|
|
* - an active object is freed
|
|
*/
|
|
static bool hrtimer_fixup_free(void *addr, enum debug_obj_state state)
|
|
{
|
|
struct hrtimer *timer = addr;
|
|
|
|
switch (state) {
|
|
case ODEBUG_STATE_ACTIVE:
|
|
hrtimer_cancel(timer);
|
|
debug_object_free(timer, &hrtimer_debug_descr);
|
|
return true;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static struct debug_obj_descr hrtimer_debug_descr = {
|
|
.name = "hrtimer",
|
|
.debug_hint = hrtimer_debug_hint,
|
|
.fixup_init = hrtimer_fixup_init,
|
|
.fixup_activate = hrtimer_fixup_activate,
|
|
.fixup_free = hrtimer_fixup_free,
|
|
};
|
|
|
|
static inline void debug_hrtimer_init(struct hrtimer *timer)
|
|
{
|
|
debug_object_init(timer, &hrtimer_debug_descr);
|
|
}
|
|
|
|
static inline void debug_hrtimer_activate(struct hrtimer *timer)
|
|
{
|
|
debug_object_activate(timer, &hrtimer_debug_descr);
|
|
}
|
|
|
|
static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
|
|
{
|
|
debug_object_deactivate(timer, &hrtimer_debug_descr);
|
|
}
|
|
|
|
static inline void debug_hrtimer_free(struct hrtimer *timer)
|
|
{
|
|
debug_object_free(timer, &hrtimer_debug_descr);
|
|
}
|
|
|
|
static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
|
|
enum hrtimer_mode mode);
|
|
|
|
void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
|
|
enum hrtimer_mode mode)
|
|
{
|
|
debug_object_init_on_stack(timer, &hrtimer_debug_descr);
|
|
__hrtimer_init(timer, clock_id, mode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
|
|
|
|
void destroy_hrtimer_on_stack(struct hrtimer *timer)
|
|
{
|
|
debug_object_free(timer, &hrtimer_debug_descr);
|
|
}
|
|
EXPORT_SYMBOL_GPL(destroy_hrtimer_on_stack);
|
|
|
|
#else
|
|
static inline void debug_hrtimer_init(struct hrtimer *timer) { }
|
|
static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
|
|
static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
|
|
#endif
|
|
|
|
static inline void
|
|
debug_init(struct hrtimer *timer, clockid_t clockid,
|
|
enum hrtimer_mode mode)
|
|
{
|
|
debug_hrtimer_init(timer);
|
|
trace_hrtimer_init(timer, clockid, mode);
|
|
}
|
|
|
|
static inline void debug_activate(struct hrtimer *timer)
|
|
{
|
|
debug_hrtimer_activate(timer);
|
|
trace_hrtimer_start(timer);
|
|
}
|
|
|
|
static inline void debug_deactivate(struct hrtimer *timer)
|
|
{
|
|
debug_hrtimer_deactivate(timer);
|
|
trace_hrtimer_cancel(timer);
|
|
}
|
|
|
|
#if defined(CONFIG_NO_HZ_COMMON) || defined(CONFIG_HIGH_RES_TIMERS)
|
|
static inline void hrtimer_update_next_timer(struct hrtimer_cpu_base *cpu_base,
|
|
struct hrtimer *timer)
|
|
{
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
cpu_base->next_timer = timer;
|
|
#endif
|
|
}
|
|
|
|
static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
|
|
{
|
|
struct hrtimer_clock_base *base = cpu_base->clock_base;
|
|
unsigned int active = cpu_base->active_bases;
|
|
ktime_t expires, expires_next = KTIME_MAX;
|
|
|
|
hrtimer_update_next_timer(cpu_base, NULL);
|
|
for (; active; base++, active >>= 1) {
|
|
struct timerqueue_node *next;
|
|
struct hrtimer *timer;
|
|
|
|
if (!(active & 0x01))
|
|
continue;
|
|
|
|
next = timerqueue_getnext(&base->active);
|
|
timer = container_of(next, struct hrtimer, node);
|
|
expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
|
|
if (expires < expires_next) {
|
|
expires_next = expires;
|
|
hrtimer_update_next_timer(cpu_base, timer);
|
|
}
|
|
}
|
|
/*
|
|
* clock_was_set() might have changed base->offset of any of
|
|
* the clock bases so the result might be negative. Fix it up
|
|
* to prevent a false positive in clockevents_program_event().
|
|
*/
|
|
if (expires_next < 0)
|
|
expires_next = 0;
|
|
return expires_next;
|
|
}
|
|
#endif
|
|
|
|
static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
|
|
{
|
|
ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
|
|
ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
|
|
ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
|
|
|
|
return ktime_get_update_offsets_now(&base->clock_was_set_seq,
|
|
offs_real, offs_boot, offs_tai);
|
|
}
|
|
|
|
/* High resolution timer related functions */
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
|
|
/*
|
|
* High resolution timer enabled ?
|
|
*/
|
|
static bool hrtimer_hres_enabled __read_mostly = true;
|
|
unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;
|
|
EXPORT_SYMBOL_GPL(hrtimer_resolution);
|
|
|
|
/*
|
|
* Enable / Disable high resolution mode
|
|
*/
|
|
static int __init setup_hrtimer_hres(char *str)
|
|
{
|
|
return (kstrtobool(str, &hrtimer_hres_enabled) == 0);
|
|
}
|
|
|
|
__setup("highres=", setup_hrtimer_hres);
|
|
|
|
/*
|
|
* hrtimer_high_res_enabled - query, if the highres mode is enabled
|
|
*/
|
|
static inline int hrtimer_is_hres_enabled(void)
|
|
{
|
|
return hrtimer_hres_enabled;
|
|
}
|
|
|
|
/*
|
|
* Is the high resolution mode active ?
|
|
*/
|
|
static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base)
|
|
{
|
|
return cpu_base->hres_active;
|
|
}
|
|
|
|
static inline int hrtimer_hres_active(void)
|
|
{
|
|
return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases));
|
|
}
|
|
|
|
/*
|
|
* Reprogram the event source with checking both queues for the
|
|
* next event
|
|
* Called with interrupts disabled and base->lock held
|
|
*/
|
|
static void
|
|
hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
|
|
{
|
|
ktime_t expires_next;
|
|
|
|
if (!cpu_base->hres_active)
|
|
return;
|
|
|
|
expires_next = __hrtimer_get_next_event(cpu_base);
|
|
|
|
if (skip_equal && expires_next == cpu_base->expires_next)
|
|
return;
|
|
|
|
cpu_base->expires_next = expires_next;
|
|
|
|
/*
|
|
* If a hang was detected in the last timer interrupt then we
|
|
* leave the hang delay active in the hardware. We want the
|
|
* system to make progress. That also prevents the following
|
|
* scenario:
|
|
* T1 expires 50ms from now
|
|
* T2 expires 5s from now
|
|
*
|
|
* T1 is removed, so this code is called and would reprogram
|
|
* the hardware to 5s from now. Any hrtimer_start after that
|
|
* will not reprogram the hardware due to hang_detected being
|
|
* set. So we'd effectivly block all timers until the T2 event
|
|
* fires.
|
|
*/
|
|
if (cpu_base->hang_detected)
|
|
return;
|
|
|
|
tick_program_event(cpu_base->expires_next, 1);
|
|
}
|
|
|
|
/*
|
|
* When a timer is enqueued and expires earlier than the already enqueued
|
|
* timers, we have to check, whether it expires earlier than the timer for
|
|
* which the clock event device was armed.
|
|
*
|
|
* Called with interrupts disabled and base->cpu_base.lock held
|
|
*/
|
|
static void hrtimer_reprogram(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
|
|
ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
|
|
|
|
WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
|
|
|
|
/*
|
|
* If the timer is not on the current cpu, we cannot reprogram
|
|
* the other cpus clock event device.
|
|
*/
|
|
if (base->cpu_base != cpu_base)
|
|
return;
|
|
|
|
/*
|
|
* If the hrtimer interrupt is running, then it will
|
|
* reevaluate the clock bases and reprogram the clock event
|
|
* device. The callbacks are always executed in hard interrupt
|
|
* context so we don't need an extra check for a running
|
|
* callback.
|
|
*/
|
|
if (cpu_base->in_hrtirq)
|
|
return;
|
|
|
|
/*
|
|
* CLOCK_REALTIME timer might be requested with an absolute
|
|
* expiry time which is less than base->offset. Set it to 0.
|
|
*/
|
|
if (expires < 0)
|
|
expires = 0;
|
|
|
|
if (expires >= cpu_base->expires_next)
|
|
return;
|
|
|
|
/* Update the pointer to the next expiring timer */
|
|
cpu_base->next_timer = timer;
|
|
|
|
/*
|
|
* If a hang was detected in the last timer interrupt then we
|
|
* do not schedule a timer which is earlier than the expiry
|
|
* which we enforced in the hang detection. We want the system
|
|
* to make progress.
|
|
*/
|
|
if (cpu_base->hang_detected)
|
|
return;
|
|
|
|
/*
|
|
* Program the timer hardware. We enforce the expiry for
|
|
* events which are already in the past.
|
|
*/
|
|
cpu_base->expires_next = expires;
|
|
tick_program_event(expires, 1);
|
|
}
|
|
|
|
/*
|
|
* Initialize the high resolution related parts of cpu_base
|
|
*/
|
|
static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
|
|
{
|
|
base->expires_next = KTIME_MAX;
|
|
base->hres_active = 0;
|
|
}
|
|
|
|
/*
|
|
* Retrigger next event is called after clock was set
|
|
*
|
|
* Called with interrupts disabled via on_each_cpu()
|
|
*/
|
|
static void retrigger_next_event(void *arg)
|
|
{
|
|
struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
|
|
|
|
if (!base->hres_active)
|
|
return;
|
|
|
|
raw_spin_lock(&base->lock);
|
|
hrtimer_update_base(base);
|
|
hrtimer_force_reprogram(base, 0);
|
|
raw_spin_unlock(&base->lock);
|
|
}
|
|
|
|
/*
|
|
* Switch to high resolution mode
|
|
*/
|
|
static void hrtimer_switch_to_hres(void)
|
|
{
|
|
struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
|
|
|
|
if (tick_init_highres()) {
|
|
printk(KERN_WARNING "Could not switch to high resolution "
|
|
"mode on CPU %d\n", base->cpu);
|
|
return;
|
|
}
|
|
base->hres_active = 1;
|
|
hrtimer_resolution = HIGH_RES_NSEC;
|
|
|
|
tick_setup_sched_timer();
|
|
/* "Retrigger" the interrupt to get things going */
|
|
retrigger_next_event(NULL);
|
|
}
|
|
|
|
static void clock_was_set_work(struct work_struct *work)
|
|
{
|
|
clock_was_set();
|
|
}
|
|
|
|
static DECLARE_WORK(hrtimer_work, clock_was_set_work);
|
|
|
|
/*
|
|
* Called from timekeeping and resume code to reprogram the hrtimer
|
|
* interrupt device on all cpus.
|
|
*/
|
|
void clock_was_set_delayed(void)
|
|
{
|
|
schedule_work(&hrtimer_work);
|
|
}
|
|
|
|
#else
|
|
|
|
static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *b) { return 0; }
|
|
static inline int hrtimer_hres_active(void) { return 0; }
|
|
static inline int hrtimer_is_hres_enabled(void) { return 0; }
|
|
static inline void hrtimer_switch_to_hres(void) { }
|
|
static inline void
|
|
hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
|
|
static inline int hrtimer_reprogram(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
|
|
static inline void retrigger_next_event(void *arg) { }
|
|
|
|
#endif /* CONFIG_HIGH_RES_TIMERS */
|
|
|
|
/*
|
|
* Clock realtime was set
|
|
*
|
|
* Change the offset of the realtime clock vs. the monotonic
|
|
* clock.
|
|
*
|
|
* We might have to reprogram the high resolution timer interrupt. On
|
|
* SMP we call the architecture specific code to retrigger _all_ high
|
|
* resolution timer interrupts. On UP we just disable interrupts and
|
|
* call the high resolution interrupt code.
|
|
*/
|
|
void clock_was_set(void)
|
|
{
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
/* Retrigger the CPU local events everywhere */
|
|
on_each_cpu(retrigger_next_event, NULL, 1);
|
|
#endif
|
|
timerfd_clock_was_set();
|
|
}
|
|
|
|
/*
|
|
* During resume we might have to reprogram the high resolution timer
|
|
* interrupt on all online CPUs. However, all other CPUs will be
|
|
* stopped with IRQs interrupts disabled so the clock_was_set() call
|
|
* must be deferred.
|
|
*/
|
|
void hrtimers_resume(void)
|
|
{
|
|
WARN_ONCE(!irqs_disabled(),
|
|
KERN_INFO "hrtimers_resume() called with IRQs enabled!");
|
|
|
|
/* Retrigger on the local CPU */
|
|
retrigger_next_event(NULL);
|
|
/* And schedule a retrigger for all others */
|
|
clock_was_set_delayed();
|
|
}
|
|
|
|
/*
|
|
* Counterpart to lock_hrtimer_base above:
|
|
*/
|
|
static inline
|
|
void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
|
|
{
|
|
raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
|
|
}
|
|
|
|
/**
|
|
* hrtimer_forward - forward the timer expiry
|
|
* @timer: hrtimer to forward
|
|
* @now: forward past this time
|
|
* @interval: the interval to forward
|
|
*
|
|
* Forward the timer expiry so it will expire in the future.
|
|
* Returns the number of overruns.
|
|
*
|
|
* Can be safely called from the callback function of @timer. If
|
|
* called from other contexts @timer must neither be enqueued nor
|
|
* running the callback and the caller needs to take care of
|
|
* serialization.
|
|
*
|
|
* Note: This only updates the timer expiry value and does not requeue
|
|
* the timer.
|
|
*/
|
|
u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
|
|
{
|
|
u64 orun = 1;
|
|
ktime_t delta;
|
|
|
|
delta = ktime_sub(now, hrtimer_get_expires(timer));
|
|
|
|
if (delta < 0)
|
|
return 0;
|
|
|
|
if (WARN_ON(timer->state & HRTIMER_STATE_ENQUEUED))
|
|
return 0;
|
|
|
|
if (interval < hrtimer_resolution)
|
|
interval = hrtimer_resolution;
|
|
|
|
if (unlikely(delta >= interval)) {
|
|
s64 incr = ktime_to_ns(interval);
|
|
|
|
orun = ktime_divns(delta, incr);
|
|
hrtimer_add_expires_ns(timer, incr * orun);
|
|
if (hrtimer_get_expires_tv64(timer) > now)
|
|
return orun;
|
|
/*
|
|
* This (and the ktime_add() below) is the
|
|
* correction for exact:
|
|
*/
|
|
orun++;
|
|
}
|
|
hrtimer_add_expires(timer, interval);
|
|
|
|
return orun;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_forward);
|
|
|
|
/*
|
|
* enqueue_hrtimer - internal function to (re)start a timer
|
|
*
|
|
* The timer is inserted in expiry order. Insertion into the
|
|
* red black tree is O(log(n)). Must hold the base lock.
|
|
*
|
|
* Returns 1 when the new timer is the leftmost timer in the tree.
|
|
*/
|
|
static int enqueue_hrtimer(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
debug_activate(timer);
|
|
|
|
base->cpu_base->active_bases |= 1 << base->index;
|
|
|
|
timer->state = HRTIMER_STATE_ENQUEUED;
|
|
|
|
return timerqueue_add(&base->active, &timer->node);
|
|
}
|
|
|
|
/*
|
|
* __remove_hrtimer - internal function to remove a timer
|
|
*
|
|
* Caller must hold the base lock.
|
|
*
|
|
* High resolution timer mode reprograms the clock event device when the
|
|
* timer is the one which expires next. The caller can disable this by setting
|
|
* reprogram to zero. This is useful, when the context does a reprogramming
|
|
* anyway (e.g. timer interrupt)
|
|
*/
|
|
static void __remove_hrtimer(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base,
|
|
u8 newstate, int reprogram)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = base->cpu_base;
|
|
u8 state = timer->state;
|
|
|
|
timer->state = newstate;
|
|
if (!(state & HRTIMER_STATE_ENQUEUED))
|
|
return;
|
|
|
|
if (!timerqueue_del(&base->active, &timer->node))
|
|
cpu_base->active_bases &= ~(1 << base->index);
|
|
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
/*
|
|
* Note: If reprogram is false we do not update
|
|
* cpu_base->next_timer. This happens when we remove the first
|
|
* timer on a remote cpu. No harm as we never dereference
|
|
* cpu_base->next_timer. So the worst thing what can happen is
|
|
* an superflous call to hrtimer_force_reprogram() on the
|
|
* remote cpu later on if the same timer gets enqueued again.
|
|
*/
|
|
if (reprogram && timer == cpu_base->next_timer)
|
|
hrtimer_force_reprogram(cpu_base, 1);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* remove hrtimer, called with base lock held
|
|
*/
|
|
static inline int
|
|
remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base, bool restart)
|
|
{
|
|
if (hrtimer_is_queued(timer)) {
|
|
u8 state = timer->state;
|
|
int reprogram;
|
|
|
|
/*
|
|
* Remove the timer and force reprogramming when high
|
|
* resolution mode is active and the timer is on the current
|
|
* CPU. If we remove a timer on another CPU, reprogramming is
|
|
* skipped. The interrupt event on this CPU is fired and
|
|
* reprogramming happens in the interrupt handler. This is a
|
|
* rare case and less expensive than a smp call.
|
|
*/
|
|
debug_deactivate(timer);
|
|
reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
|
|
|
|
if (!restart)
|
|
state = HRTIMER_STATE_INACTIVE;
|
|
|
|
__remove_hrtimer(timer, base, state, reprogram);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static inline ktime_t hrtimer_update_lowres(struct hrtimer *timer, ktime_t tim,
|
|
const enum hrtimer_mode mode)
|
|
{
|
|
#ifdef CONFIG_TIME_LOW_RES
|
|
/*
|
|
* CONFIG_TIME_LOW_RES indicates that the system has no way to return
|
|
* granular time values. For relative timers we add hrtimer_resolution
|
|
* (i.e. one jiffie) to prevent short timeouts.
|
|
*/
|
|
timer->is_rel = mode & HRTIMER_MODE_REL;
|
|
if (timer->is_rel)
|
|
tim = ktime_add_safe(tim, hrtimer_resolution);
|
|
#endif
|
|
return tim;
|
|
}
|
|
|
|
/**
|
|
* hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
|
|
* @timer: the timer to be added
|
|
* @tim: expiry time
|
|
* @delta_ns: "slack" range for the timer
|
|
* @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
|
|
* relative (HRTIMER_MODE_REL)
|
|
*/
|
|
void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
|
|
u64 delta_ns, const enum hrtimer_mode mode)
|
|
{
|
|
struct hrtimer_clock_base *base, *new_base;
|
|
unsigned long flags;
|
|
int leftmost;
|
|
|
|
base = lock_hrtimer_base(timer, &flags);
|
|
|
|
/* Remove an active timer from the queue: */
|
|
remove_hrtimer(timer, base, true);
|
|
|
|
if (mode & HRTIMER_MODE_REL)
|
|
tim = ktime_add_safe(tim, base->get_time());
|
|
|
|
tim = hrtimer_update_lowres(timer, tim, mode);
|
|
|
|
hrtimer_set_expires_range_ns(timer, tim, delta_ns);
|
|
|
|
/* Switch the timer base, if necessary: */
|
|
new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
|
|
|
|
leftmost = enqueue_hrtimer(timer, new_base);
|
|
if (!leftmost)
|
|
goto unlock;
|
|
|
|
if (!hrtimer_is_hres_active(timer)) {
|
|
/*
|
|
* Kick to reschedule the next tick to handle the new timer
|
|
* on dynticks target.
|
|
*/
|
|
if (new_base->cpu_base->nohz_active)
|
|
wake_up_nohz_cpu(new_base->cpu_base->cpu);
|
|
} else {
|
|
hrtimer_reprogram(timer, new_base);
|
|
}
|
|
unlock:
|
|
unlock_hrtimer_base(timer, &flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
|
|
|
|
/**
|
|
* hrtimer_try_to_cancel - try to deactivate a timer
|
|
* @timer: hrtimer to stop
|
|
*
|
|
* Returns:
|
|
* 0 when the timer was not active
|
|
* 1 when the timer was active
|
|
* -1 when the timer is currently excuting the callback function and
|
|
* cannot be stopped
|
|
*/
|
|
int hrtimer_try_to_cancel(struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_clock_base *base;
|
|
unsigned long flags;
|
|
int ret = -1;
|
|
|
|
/*
|
|
* Check lockless first. If the timer is not active (neither
|
|
* enqueued nor running the callback, nothing to do here. The
|
|
* base lock does not serialize against a concurrent enqueue,
|
|
* so we can avoid taking it.
|
|
*/
|
|
if (!hrtimer_active(timer))
|
|
return 0;
|
|
|
|
base = lock_hrtimer_base(timer, &flags);
|
|
|
|
if (!hrtimer_callback_running(timer))
|
|
ret = remove_hrtimer(timer, base, false);
|
|
|
|
unlock_hrtimer_base(timer, &flags);
|
|
|
|
return ret;
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
|
|
|
|
/**
|
|
* hrtimer_cancel - cancel a timer and wait for the handler to finish.
|
|
* @timer: the timer to be cancelled
|
|
*
|
|
* Returns:
|
|
* 0 when the timer was not active
|
|
* 1 when the timer was active
|
|
*/
|
|
int hrtimer_cancel(struct hrtimer *timer)
|
|
{
|
|
for (;;) {
|
|
int ret = hrtimer_try_to_cancel(timer);
|
|
|
|
if (ret >= 0)
|
|
return ret;
|
|
cpu_relax();
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_cancel);
|
|
|
|
/**
|
|
* hrtimer_get_remaining - get remaining time for the timer
|
|
* @timer: the timer to read
|
|
* @adjust: adjust relative timers when CONFIG_TIME_LOW_RES=y
|
|
*/
|
|
ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust)
|
|
{
|
|
unsigned long flags;
|
|
ktime_t rem;
|
|
|
|
lock_hrtimer_base(timer, &flags);
|
|
if (IS_ENABLED(CONFIG_TIME_LOW_RES) && adjust)
|
|
rem = hrtimer_expires_remaining_adjusted(timer);
|
|
else
|
|
rem = hrtimer_expires_remaining(timer);
|
|
unlock_hrtimer_base(timer, &flags);
|
|
|
|
return rem;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__hrtimer_get_remaining);
|
|
|
|
#ifdef CONFIG_NO_HZ_COMMON
|
|
/**
|
|
* hrtimer_get_next_event - get the time until next expiry event
|
|
*
|
|
* Returns the next expiry time or KTIME_MAX if no timer is pending.
|
|
*/
|
|
u64 hrtimer_get_next_event(void)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
|
|
u64 expires = KTIME_MAX;
|
|
unsigned long flags;
|
|
|
|
raw_spin_lock_irqsave(&cpu_base->lock, flags);
|
|
|
|
if (!__hrtimer_hres_active(cpu_base))
|
|
expires = __hrtimer_get_next_event(cpu_base);
|
|
|
|
raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
|
|
|
|
return expires;
|
|
}
|
|
#endif
|
|
|
|
static inline int hrtimer_clockid_to_base(clockid_t clock_id)
|
|
{
|
|
if (likely(clock_id < MAX_CLOCKS)) {
|
|
int base = hrtimer_clock_to_base_table[clock_id];
|
|
|
|
if (likely(base != HRTIMER_MAX_CLOCK_BASES))
|
|
return base;
|
|
}
|
|
WARN(1, "Invalid clockid %d. Using MONOTONIC\n", clock_id);
|
|
return HRTIMER_BASE_MONOTONIC;
|
|
}
|
|
|
|
static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
|
|
enum hrtimer_mode mode)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base;
|
|
int base;
|
|
|
|
memset(timer, 0, sizeof(struct hrtimer));
|
|
|
|
cpu_base = raw_cpu_ptr(&hrtimer_bases);
|
|
|
|
if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
|
|
clock_id = CLOCK_MONOTONIC;
|
|
|
|
base = hrtimer_clockid_to_base(clock_id);
|
|
timer->base = &cpu_base->clock_base[base];
|
|
timerqueue_init(&timer->node);
|
|
}
|
|
|
|
/**
|
|
* hrtimer_init - initialize a timer to the given clock
|
|
* @timer: the timer to be initialized
|
|
* @clock_id: the clock to be used
|
|
* @mode: timer mode abs/rel
|
|
*/
|
|
void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
|
|
enum hrtimer_mode mode)
|
|
{
|
|
debug_init(timer, clock_id, mode);
|
|
__hrtimer_init(timer, clock_id, mode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_init);
|
|
|
|
/*
|
|
* A timer is active, when it is enqueued into the rbtree or the
|
|
* callback function is running or it's in the state of being migrated
|
|
* to another cpu.
|
|
*
|
|
* It is important for this function to not return a false negative.
|
|
*/
|
|
bool hrtimer_active(const struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base;
|
|
unsigned int seq;
|
|
|
|
do {
|
|
cpu_base = READ_ONCE(timer->base->cpu_base);
|
|
seq = raw_read_seqcount_begin(&cpu_base->seq);
|
|
|
|
if (timer->state != HRTIMER_STATE_INACTIVE ||
|
|
cpu_base->running == timer)
|
|
return true;
|
|
|
|
} while (read_seqcount_retry(&cpu_base->seq, seq) ||
|
|
cpu_base != READ_ONCE(timer->base->cpu_base));
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_active);
|
|
|
|
/*
|
|
* The write_seqcount_barrier()s in __run_hrtimer() split the thing into 3
|
|
* distinct sections:
|
|
*
|
|
* - queued: the timer is queued
|
|
* - callback: the timer is being ran
|
|
* - post: the timer is inactive or (re)queued
|
|
*
|
|
* On the read side we ensure we observe timer->state and cpu_base->running
|
|
* from the same section, if anything changed while we looked at it, we retry.
|
|
* This includes timer->base changing because sequence numbers alone are
|
|
* insufficient for that.
|
|
*
|
|
* The sequence numbers are required because otherwise we could still observe
|
|
* a false negative if the read side got smeared over multiple consequtive
|
|
* __run_hrtimer() invocations.
|
|
*/
|
|
|
|
static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
|
|
struct hrtimer_clock_base *base,
|
|
struct hrtimer *timer, ktime_t *now)
|
|
{
|
|
enum hrtimer_restart (*fn)(struct hrtimer *);
|
|
int restart;
|
|
|
|
lockdep_assert_held(&cpu_base->lock);
|
|
|
|
debug_deactivate(timer);
|
|
cpu_base->running = timer;
|
|
|
|
/*
|
|
* Separate the ->running assignment from the ->state assignment.
|
|
*
|
|
* As with a regular write barrier, this ensures the read side in
|
|
* hrtimer_active() cannot observe cpu_base->running == NULL &&
|
|
* timer->state == INACTIVE.
|
|
*/
|
|
raw_write_seqcount_barrier(&cpu_base->seq);
|
|
|
|
__remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, 0);
|
|
fn = timer->function;
|
|
|
|
/*
|
|
* Clear the 'is relative' flag for the TIME_LOW_RES case. If the
|
|
* timer is restarted with a period then it becomes an absolute
|
|
* timer. If its not restarted it does not matter.
|
|
*/
|
|
if (IS_ENABLED(CONFIG_TIME_LOW_RES))
|
|
timer->is_rel = false;
|
|
|
|
/*
|
|
* Because we run timers from hardirq context, there is no chance
|
|
* they get migrated to another cpu, therefore its safe to unlock
|
|
* the timer base.
|
|
*/
|
|
raw_spin_unlock(&cpu_base->lock);
|
|
trace_hrtimer_expire_entry(timer, now);
|
|
restart = fn(timer);
|
|
trace_hrtimer_expire_exit(timer);
|
|
raw_spin_lock(&cpu_base->lock);
|
|
|
|
/*
|
|
* Note: We clear the running state after enqueue_hrtimer and
|
|
* we do not reprogram the event hardware. Happens either in
|
|
* hrtimer_start_range_ns() or in hrtimer_interrupt()
|
|
*
|
|
* Note: Because we dropped the cpu_base->lock above,
|
|
* hrtimer_start_range_ns() can have popped in and enqueued the timer
|
|
* for us already.
|
|
*/
|
|
if (restart != HRTIMER_NORESTART &&
|
|
!(timer->state & HRTIMER_STATE_ENQUEUED))
|
|
enqueue_hrtimer(timer, base);
|
|
|
|
/*
|
|
* Separate the ->running assignment from the ->state assignment.
|
|
*
|
|
* As with a regular write barrier, this ensures the read side in
|
|
* hrtimer_active() cannot observe cpu_base->running == NULL &&
|
|
* timer->state == INACTIVE.
|
|
*/
|
|
raw_write_seqcount_barrier(&cpu_base->seq);
|
|
|
|
WARN_ON_ONCE(cpu_base->running != timer);
|
|
cpu_base->running = NULL;
|
|
}
|
|
|
|
static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now)
|
|
{
|
|
struct hrtimer_clock_base *base = cpu_base->clock_base;
|
|
unsigned int active = cpu_base->active_bases;
|
|
|
|
for (; active; base++, active >>= 1) {
|
|
struct timerqueue_node *node;
|
|
ktime_t basenow;
|
|
|
|
if (!(active & 0x01))
|
|
continue;
|
|
|
|
basenow = ktime_add(now, base->offset);
|
|
|
|
while ((node = timerqueue_getnext(&base->active))) {
|
|
struct hrtimer *timer;
|
|
|
|
timer = container_of(node, struct hrtimer, node);
|
|
|
|
/*
|
|
* The immediate goal for using the softexpires is
|
|
* minimizing wakeups, not running timers at the
|
|
* earliest interrupt after their soft expiration.
|
|
* This allows us to avoid using a Priority Search
|
|
* Tree, which can answer a stabbing querry for
|
|
* overlapping intervals and instead use the simple
|
|
* BST we already have.
|
|
* We don't add extra wakeups by delaying timers that
|
|
* are right-of a not yet expired timer, because that
|
|
* timer will have to trigger a wakeup anyway.
|
|
*/
|
|
if (basenow < hrtimer_get_softexpires_tv64(timer))
|
|
break;
|
|
|
|
__run_hrtimer(cpu_base, base, timer, &basenow);
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
|
|
/*
|
|
* High resolution timer interrupt
|
|
* Called with interrupts disabled
|
|
*/
|
|
void hrtimer_interrupt(struct clock_event_device *dev)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
|
|
ktime_t expires_next, now, entry_time, delta;
|
|
int retries = 0;
|
|
|
|
BUG_ON(!cpu_base->hres_active);
|
|
cpu_base->nr_events++;
|
|
dev->next_event = KTIME_MAX;
|
|
|
|
raw_spin_lock(&cpu_base->lock);
|
|
entry_time = now = hrtimer_update_base(cpu_base);
|
|
retry:
|
|
cpu_base->in_hrtirq = 1;
|
|
/*
|
|
* We set expires_next to KTIME_MAX here with cpu_base->lock
|
|
* held to prevent that a timer is enqueued in our queue via
|
|
* the migration code. This does not affect enqueueing of
|
|
* timers which run their callback and need to be requeued on
|
|
* this CPU.
|
|
*/
|
|
cpu_base->expires_next = KTIME_MAX;
|
|
|
|
__hrtimer_run_queues(cpu_base, now);
|
|
|
|
/* Reevaluate the clock bases for the next expiry */
|
|
expires_next = __hrtimer_get_next_event(cpu_base);
|
|
/*
|
|
* Store the new expiry value so the migration code can verify
|
|
* against it.
|
|
*/
|
|
cpu_base->expires_next = expires_next;
|
|
cpu_base->in_hrtirq = 0;
|
|
raw_spin_unlock(&cpu_base->lock);
|
|
|
|
/* Reprogramming necessary ? */
|
|
if (!tick_program_event(expires_next, 0)) {
|
|
cpu_base->hang_detected = 0;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* The next timer was already expired due to:
|
|
* - tracing
|
|
* - long lasting callbacks
|
|
* - being scheduled away when running in a VM
|
|
*
|
|
* We need to prevent that we loop forever in the hrtimer
|
|
* interrupt routine. We give it 3 attempts to avoid
|
|
* overreacting on some spurious event.
|
|
*
|
|
* Acquire base lock for updating the offsets and retrieving
|
|
* the current time.
|
|
*/
|
|
raw_spin_lock(&cpu_base->lock);
|
|
now = hrtimer_update_base(cpu_base);
|
|
cpu_base->nr_retries++;
|
|
if (++retries < 3)
|
|
goto retry;
|
|
/*
|
|
* Give the system a chance to do something else than looping
|
|
* here. We stored the entry time, so we know exactly how long
|
|
* we spent here. We schedule the next event this amount of
|
|
* time away.
|
|
*/
|
|
cpu_base->nr_hangs++;
|
|
cpu_base->hang_detected = 1;
|
|
raw_spin_unlock(&cpu_base->lock);
|
|
delta = ktime_sub(now, entry_time);
|
|
if ((unsigned int)delta > cpu_base->max_hang_time)
|
|
cpu_base->max_hang_time = (unsigned int) delta;
|
|
/*
|
|
* Limit it to a sensible value as we enforce a longer
|
|
* delay. Give the CPU at least 100ms to catch up.
|
|
*/
|
|
if (delta > 100 * NSEC_PER_MSEC)
|
|
expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
|
|
else
|
|
expires_next = ktime_add(now, delta);
|
|
tick_program_event(expires_next, 1);
|
|
printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
|
|
ktime_to_ns(delta));
|
|
}
|
|
|
|
/*
|
|
* local version of hrtimer_peek_ahead_timers() called with interrupts
|
|
* disabled.
|
|
*/
|
|
static inline void __hrtimer_peek_ahead_timers(void)
|
|
{
|
|
struct tick_device *td;
|
|
|
|
if (!hrtimer_hres_active())
|
|
return;
|
|
|
|
td = this_cpu_ptr(&tick_cpu_device);
|
|
if (td && td->evtdev)
|
|
hrtimer_interrupt(td->evtdev);
|
|
}
|
|
|
|
#else /* CONFIG_HIGH_RES_TIMERS */
|
|
|
|
static inline void __hrtimer_peek_ahead_timers(void) { }
|
|
|
|
#endif /* !CONFIG_HIGH_RES_TIMERS */
|
|
|
|
/*
|
|
* Called from run_local_timers in hardirq context every jiffy
|
|
*/
|
|
void hrtimer_run_queues(void)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
|
|
ktime_t now;
|
|
|
|
if (__hrtimer_hres_active(cpu_base))
|
|
return;
|
|
|
|
/*
|
|
* This _is_ ugly: We have to check periodically, whether we
|
|
* can switch to highres and / or nohz mode. The clocksource
|
|
* switch happens with xtime_lock held. Notification from
|
|
* there only sets the check bit in the tick_oneshot code,
|
|
* otherwise we might deadlock vs. xtime_lock.
|
|
*/
|
|
if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())) {
|
|
hrtimer_switch_to_hres();
|
|
return;
|
|
}
|
|
|
|
raw_spin_lock(&cpu_base->lock);
|
|
now = hrtimer_update_base(cpu_base);
|
|
__hrtimer_run_queues(cpu_base, now);
|
|
raw_spin_unlock(&cpu_base->lock);
|
|
}
|
|
|
|
/*
|
|
* Sleep related functions:
|
|
*/
|
|
static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_sleeper *t =
|
|
container_of(timer, struct hrtimer_sleeper, timer);
|
|
struct task_struct *task = t->task;
|
|
|
|
t->task = NULL;
|
|
if (task)
|
|
wake_up_process(task);
|
|
|
|
return HRTIMER_NORESTART;
|
|
}
|
|
|
|
void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
|
|
{
|
|
sl->timer.function = hrtimer_wakeup;
|
|
sl->task = task;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
|
|
|
|
static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
|
|
{
|
|
hrtimer_init_sleeper(t, current);
|
|
|
|
do {
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
hrtimer_start_expires(&t->timer, mode);
|
|
|
|
if (likely(t->task))
|
|
freezable_schedule();
|
|
|
|
hrtimer_cancel(&t->timer);
|
|
mode = HRTIMER_MODE_ABS;
|
|
|
|
} while (t->task && !signal_pending(current));
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
return t->task == NULL;
|
|
}
|
|
|
|
static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
|
|
{
|
|
struct timespec rmt;
|
|
ktime_t rem;
|
|
|
|
rem = hrtimer_expires_remaining(timer);
|
|
if (rem <= 0)
|
|
return 0;
|
|
rmt = ktime_to_timespec(rem);
|
|
|
|
if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
|
|
return -EFAULT;
|
|
|
|
return 1;
|
|
}
|
|
|
|
long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
|
|
{
|
|
struct hrtimer_sleeper t;
|
|
struct timespec __user *rmtp;
|
|
int ret = 0;
|
|
|
|
hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,
|
|
HRTIMER_MODE_ABS);
|
|
hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
|
|
|
|
if (do_nanosleep(&t, HRTIMER_MODE_ABS))
|
|
goto out;
|
|
|
|
rmtp = restart->nanosleep.rmtp;
|
|
if (rmtp) {
|
|
ret = update_rmtp(&t.timer, rmtp);
|
|
if (ret <= 0)
|
|
goto out;
|
|
}
|
|
|
|
/* The other values in restart are already filled in */
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
out:
|
|
destroy_hrtimer_on_stack(&t.timer);
|
|
return ret;
|
|
}
|
|
|
|
long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
|
|
const enum hrtimer_mode mode, const clockid_t clockid)
|
|
{
|
|
struct restart_block *restart;
|
|
struct hrtimer_sleeper t;
|
|
int ret = 0;
|
|
u64 slack;
|
|
|
|
slack = current->timer_slack_ns;
|
|
if (dl_task(current) || rt_task(current))
|
|
slack = 0;
|
|
|
|
hrtimer_init_on_stack(&t.timer, clockid, mode);
|
|
hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
|
|
if (do_nanosleep(&t, mode))
|
|
goto out;
|
|
|
|
/* Absolute timers do not update the rmtp value and restart: */
|
|
if (mode == HRTIMER_MODE_ABS) {
|
|
ret = -ERESTARTNOHAND;
|
|
goto out;
|
|
}
|
|
|
|
if (rmtp) {
|
|
ret = update_rmtp(&t.timer, rmtp);
|
|
if (ret <= 0)
|
|
goto out;
|
|
}
|
|
|
|
restart = ¤t->restart_block;
|
|
restart->fn = hrtimer_nanosleep_restart;
|
|
restart->nanosleep.clockid = t.timer.base->clockid;
|
|
restart->nanosleep.rmtp = rmtp;
|
|
restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
|
|
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
out:
|
|
destroy_hrtimer_on_stack(&t.timer);
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
|
|
struct timespec __user *, rmtp)
|
|
{
|
|
struct timespec tu;
|
|
|
|
if (copy_from_user(&tu, rqtp, sizeof(tu)))
|
|
return -EFAULT;
|
|
|
|
if (!timespec_valid(&tu))
|
|
return -EINVAL;
|
|
|
|
return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
|
|
}
|
|
|
|
/*
|
|
* Functions related to boot-time initialization:
|
|
*/
|
|
int hrtimers_prepare_cpu(unsigned int cpu)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
|
|
int i;
|
|
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
|
|
cpu_base->clock_base[i].cpu_base = cpu_base;
|
|
timerqueue_init_head(&cpu_base->clock_base[i].active);
|
|
}
|
|
|
|
cpu_base->cpu = cpu;
|
|
hrtimer_init_hres(cpu_base);
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
|
|
struct hrtimer_clock_base *new_base)
|
|
{
|
|
struct hrtimer *timer;
|
|
struct timerqueue_node *node;
|
|
|
|
while ((node = timerqueue_getnext(&old_base->active))) {
|
|
timer = container_of(node, struct hrtimer, node);
|
|
BUG_ON(hrtimer_callback_running(timer));
|
|
debug_deactivate(timer);
|
|
|
|
/*
|
|
* Mark it as ENQUEUED not INACTIVE otherwise the
|
|
* timer could be seen as !active and just vanish away
|
|
* under us on another CPU
|
|
*/
|
|
__remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);
|
|
timer->base = new_base;
|
|
/*
|
|
* Enqueue the timers on the new cpu. This does not
|
|
* reprogram the event device in case the timer
|
|
* expires before the earliest on this CPU, but we run
|
|
* hrtimer_interrupt after we migrated everything to
|
|
* sort out already expired timers and reprogram the
|
|
* event device.
|
|
*/
|
|
enqueue_hrtimer(timer, new_base);
|
|
}
|
|
}
|
|
|
|
int hrtimers_dead_cpu(unsigned int scpu)
|
|
{
|
|
struct hrtimer_cpu_base *old_base, *new_base;
|
|
int i;
|
|
|
|
BUG_ON(cpu_online(scpu));
|
|
tick_cancel_sched_timer(scpu);
|
|
|
|
local_irq_disable();
|
|
old_base = &per_cpu(hrtimer_bases, scpu);
|
|
new_base = this_cpu_ptr(&hrtimer_bases);
|
|
/*
|
|
* The caller is globally serialized and nobody else
|
|
* takes two locks at once, deadlock is not possible.
|
|
*/
|
|
raw_spin_lock(&new_base->lock);
|
|
raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
|
|
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
|
|
migrate_hrtimer_list(&old_base->clock_base[i],
|
|
&new_base->clock_base[i]);
|
|
}
|
|
|
|
raw_spin_unlock(&old_base->lock);
|
|
raw_spin_unlock(&new_base->lock);
|
|
|
|
/* Check, if we got expired work to do */
|
|
__hrtimer_peek_ahead_timers();
|
|
local_irq_enable();
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_HOTPLUG_CPU */
|
|
|
|
void __init hrtimers_init(void)
|
|
{
|
|
hrtimers_prepare_cpu(smp_processor_id());
|
|
}
|
|
|
|
/**
|
|
* schedule_hrtimeout_range_clock - sleep until timeout
|
|
* @expires: timeout value (ktime_t)
|
|
* @delta: slack in expires timeout (ktime_t)
|
|
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
|
|
* @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
|
|
*/
|
|
int __sched
|
|
schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta,
|
|
const enum hrtimer_mode mode, int clock)
|
|
{
|
|
struct hrtimer_sleeper t;
|
|
|
|
/*
|
|
* Optimize when a zero timeout value is given. It does not
|
|
* matter whether this is an absolute or a relative time.
|
|
*/
|
|
if (expires && *expires == 0) {
|
|
__set_current_state(TASK_RUNNING);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* A NULL parameter means "infinite"
|
|
*/
|
|
if (!expires) {
|
|
schedule();
|
|
return -EINTR;
|
|
}
|
|
|
|
hrtimer_init_on_stack(&t.timer, clock, mode);
|
|
hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
|
|
|
|
hrtimer_init_sleeper(&t, current);
|
|
|
|
hrtimer_start_expires(&t.timer, mode);
|
|
|
|
if (likely(t.task))
|
|
schedule();
|
|
|
|
hrtimer_cancel(&t.timer);
|
|
destroy_hrtimer_on_stack(&t.timer);
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
return !t.task ? 0 : -EINTR;
|
|
}
|
|
|
|
/**
|
|
* schedule_hrtimeout_range - sleep until timeout
|
|
* @expires: timeout value (ktime_t)
|
|
* @delta: slack in expires timeout (ktime_t)
|
|
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
|
|
*
|
|
* Make the current task sleep until the given expiry time has
|
|
* elapsed. The routine will return immediately unless
|
|
* the current task state has been set (see set_current_state()).
|
|
*
|
|
* The @delta argument gives the kernel the freedom to schedule the
|
|
* actual wakeup to a time that is both power and performance friendly.
|
|
* The kernel give the normal best effort behavior for "@expires+@delta",
|
|
* but may decide to fire the timer earlier, but no earlier than @expires.
|
|
*
|
|
* You can set the task state as follows -
|
|
*
|
|
* %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
|
|
* pass before the routine returns unless the current task is explicitly
|
|
* woken up, (e.g. by wake_up_process()).
|
|
*
|
|
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
|
|
* delivered to the current task or the current task is explicitly woken
|
|
* up.
|
|
*
|
|
* The current task state is guaranteed to be TASK_RUNNING when this
|
|
* routine returns.
|
|
*
|
|
* Returns 0 when the timer has expired. If the task was woken before the
|
|
* timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
|
|
* by an explicit wakeup, it returns -EINTR.
|
|
*/
|
|
int __sched schedule_hrtimeout_range(ktime_t *expires, u64 delta,
|
|
const enum hrtimer_mode mode)
|
|
{
|
|
return schedule_hrtimeout_range_clock(expires, delta, mode,
|
|
CLOCK_MONOTONIC);
|
|
}
|
|
EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
|
|
|
|
/**
|
|
* schedule_hrtimeout - sleep until timeout
|
|
* @expires: timeout value (ktime_t)
|
|
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
|
|
*
|
|
* Make the current task sleep until the given expiry time has
|
|
* elapsed. The routine will return immediately unless
|
|
* the current task state has been set (see set_current_state()).
|
|
*
|
|
* You can set the task state as follows -
|
|
*
|
|
* %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
|
|
* pass before the routine returns unless the current task is explicitly
|
|
* woken up, (e.g. by wake_up_process()).
|
|
*
|
|
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
|
|
* delivered to the current task or the current task is explicitly woken
|
|
* up.
|
|
*
|
|
* The current task state is guaranteed to be TASK_RUNNING when this
|
|
* routine returns.
|
|
*
|
|
* Returns 0 when the timer has expired. If the task was woken before the
|
|
* timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
|
|
* by an explicit wakeup, it returns -EINTR.
|
|
*/
|
|
int __sched schedule_hrtimeout(ktime_t *expires,
|
|
const enum hrtimer_mode mode)
|
|
{
|
|
return schedule_hrtimeout_range(expires, 0, mode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(schedule_hrtimeout);
|