| /* |
| * 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.h> |
| #include <linux/sched/sysctl.h> |
| #include <linux/sched/rt.h> |
| #include <linux/timer.h> |
| |
| #include <asm/uaccess.h> |
| |
| #include <trace/events/timer.h> |
| |
| /* |
| * The timer bases: |
| * |
| * There are more clockids then 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), |
| .clock_base = |
| { |
| { |
| .index = HRTIMER_BASE_MONOTONIC, |
| .clockid = CLOCK_MONOTONIC, |
| .get_time = &ktime_get, |
| .resolution = KTIME_LOW_RES, |
| }, |
| { |
| .index = HRTIMER_BASE_REALTIME, |
| .clockid = CLOCK_REALTIME, |
| .get_time = &ktime_get_real, |
| .resolution = KTIME_LOW_RES, |
| }, |
| { |
| .index = HRTIMER_BASE_BOOTTIME, |
| .clockid = CLOCK_BOOTTIME, |
| .get_time = &ktime_get_boottime, |
| .resolution = KTIME_LOW_RES, |
| }, |
| { |
| .index = HRTIMER_BASE_TAI, |
| .clockid = CLOCK_TAI, |
| .get_time = &ktime_get_clocktai, |
| .resolution = KTIME_LOW_RES, |
| }, |
| } |
| }; |
| |
| static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = { |
| [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME, |
| [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC, |
| [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME, |
| [CLOCK_TAI] = HRTIMER_BASE_TAI, |
| }; |
| |
| static inline int hrtimer_clockid_to_base(clockid_t clock_id) |
| { |
| return hrtimer_clock_to_base_table[clock_id]; |
| } |
| |
| |
| /* |
| * Get the coarse grained time at the softirq based on xtime and |
| * wall_to_monotonic. |
| */ |
| static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base) |
| { |
| ktime_t xtim, mono, boot; |
| struct timespec xts, tom, slp; |
| s32 tai_offset; |
| |
| get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp); |
| tai_offset = timekeeping_get_tai_offset(); |
| |
| xtim = timespec_to_ktime(xts); |
| 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 = mono; |
| base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot; |
| base->clock_base[HRTIMER_BASE_TAI].softirq_time = |
| ktime_add(xtim, ktime_set(tai_offset, 0)); |
| } |
| |
| /* |
| * Functions and macros which are different for UP/SMP systems are kept in a |
| * single place |
| */ |
| #ifdef CONFIG_SMP |
| |
| /* |
| * 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 = NULL 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 != NULL)) { |
| 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(); |
| } |
| } |
| |
| |
| /* |
| * Get the preferred target CPU for NOHZ |
| */ |
| static int hrtimer_get_target(int this_cpu, int pinned) |
| { |
| #ifdef CONFIG_NO_HZ_COMMON |
| if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu)) |
| return get_nohz_timer_target(); |
| #endif |
| return this_cpu; |
| } |
| |
| /* |
| * 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.tv64 <= new_base->cpu_base->expires_next.tv64; |
| #else |
| return 0; |
| #endif |
| } |
| |
| /* |
| * Switch the timer base to the current CPU when possible. |
| */ |
| static inline struct hrtimer_clock_base * |
| switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base, |
| int pinned) |
| { |
| struct hrtimer_clock_base *new_base; |
| struct hrtimer_cpu_base *new_cpu_base; |
| int this_cpu = smp_processor_id(); |
| int cpu = hrtimer_get_target(this_cpu, pinned); |
| int basenum = base->index; |
| |
| again: |
| new_cpu_base = &per_cpu(hrtimer_bases, cpu); |
| 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_timer_base() */ |
| timer->base = NULL; |
| raw_spin_unlock(&base->cpu_base->lock); |
| raw_spin_lock(&new_base->cpu_base->lock); |
| |
| if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) { |
| cpu = this_cpu; |
| raw_spin_unlock(&new_base->cpu_base->lock); |
| raw_spin_lock(&base->cpu_base->lock); |
| timer->base = base; |
| goto again; |
| } |
| timer->base = new_base; |
| } else { |
| if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) { |
| cpu = this_cpu; |
| 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 |
| # ifndef CONFIG_KTIME_SCALAR |
| /** |
| * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable |
| * @kt: addend |
| * @nsec: the scalar nsec value to add |
| * |
| * Returns the sum of kt and nsec in ktime_t format |
| */ |
| ktime_t ktime_add_ns(const ktime_t kt, u64 nsec) |
| { |
| ktime_t tmp; |
| |
| if (likely(nsec < NSEC_PER_SEC)) { |
| tmp.tv64 = nsec; |
| } else { |
| unsigned long rem = do_div(nsec, NSEC_PER_SEC); |
| |
| /* Make sure nsec fits into long */ |
| if (unlikely(nsec > KTIME_SEC_MAX)) |
| return (ktime_t){ .tv64 = KTIME_MAX }; |
| |
| tmp = ktime_set((long)nsec, rem); |
| } |
| |
| return ktime_add(kt, tmp); |
| } |
| |
| EXPORT_SYMBOL_GPL(ktime_add_ns); |
| |
| /** |
| * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable |
| * @kt: minuend |
| * @nsec: the scalar nsec value to subtract |
| * |
| * Returns the subtraction of @nsec from @kt in ktime_t format |
| */ |
| ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec) |
| { |
| ktime_t tmp; |
| |
| if (likely(nsec < NSEC_PER_SEC)) { |
| tmp.tv64 = nsec; |
| } else { |
| unsigned long rem = do_div(nsec, NSEC_PER_SEC); |
| |
| tmp = ktime_set((long)nsec, rem); |
| } |
| |
| return ktime_sub(kt, tmp); |
| } |
| |
| EXPORT_SYMBOL_GPL(ktime_sub_ns); |
| # endif /* !CONFIG_KTIME_SCALAR */ |
| |
| /* |
| * Divide a ktime value by a nanosecond value |
| */ |
| u64 ktime_divns(const ktime_t kt, s64 div) |
| { |
| u64 dclc; |
| int sft = 0; |
| |
| dclc = ktime_to_ns(kt); |
| /* Make sure the divisor is less than 2^32: */ |
| while (div >> 32) { |
| sft++; |
| div >>= 1; |
| } |
| dclc >>= sft; |
| do_div(dclc, (unsigned long) div); |
| |
| return dclc; |
| } |
| #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(lhs, rhs); |
| |
| /* |
| * We use KTIME_SEC_MAX here, the maximum timeout which we can |
| * return to user space in a timespec: |
| */ |
| if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64) |
| 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 int 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 1; |
| default: |
| return 0; |
| } |
| } |
| |
| /* |
| * fixup_activate is called when: |
| * - an active object is activated |
| * - an unknown object is activated (might be a statically initialized object) |
| */ |
| static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state) |
| { |
| switch (state) { |
| |
| case ODEBUG_STATE_NOTAVAILABLE: |
| WARN_ON_ONCE(1); |
| return 0; |
| |
| case ODEBUG_STATE_ACTIVE: |
| WARN_ON(1); |
| |
| default: |
| return 0; |
| } |
| } |
| |
| /* |
| * fixup_free is called when: |
| * - an active object is freed |
| */ |
| static int 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 1; |
| default: |
| return 0; |
| } |
| } |
| |
| 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); |
| } |
| |
| #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); |
| } |
| |
| /* High resolution timer related functions */ |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| |
| /* |
| * High resolution timer enabled ? |
| */ |
| static int hrtimer_hres_enabled __read_mostly = 1; |
| |
| /* |
| * Enable / Disable high resolution mode |
| */ |
| static int __init setup_hrtimer_hres(char *str) |
| { |
| if (!strcmp(str, "off")) |
| hrtimer_hres_enabled = 0; |
| else if (!strcmp(str, "on")) |
| hrtimer_hres_enabled = 1; |
| else |
| return 0; |
| return 1; |
| } |
| |
| __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(void) |
| { |
| return __this_cpu_read(hrtimer_bases.hres_active); |
| } |
| |
| /* |
| * 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) |
| { |
| int i; |
| struct hrtimer_clock_base *base = cpu_base->clock_base; |
| ktime_t expires, expires_next; |
| |
| expires_next.tv64 = KTIME_MAX; |
| |
| for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { |
| struct hrtimer *timer; |
| struct timerqueue_node *next; |
| |
| next = timerqueue_getnext(&base->active); |
| if (!next) |
| continue; |
| timer = container_of(next, struct hrtimer, node); |
| |
| expires = ktime_sub(hrtimer_get_expires(timer), base->offset); |
| /* |
| * clock_was_set() has changed base->offset so the |
| * result might be negative. Fix it up to prevent a |
| * false positive in clockevents_program_event() |
| */ |
| if (expires.tv64 < 0) |
| expires.tv64 = 0; |
| if (expires.tv64 < expires_next.tv64) |
| expires_next = expires; |
| } |
| |
| if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64) |
| return; |
| |
| cpu_base->expires_next.tv64 = expires_next.tv64; |
| |
| /* |
| * 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; |
| |
| if (cpu_base->expires_next.tv64 != KTIME_MAX) |
| tick_program_event(cpu_base->expires_next, 1); |
| } |
| |
| /* |
| * Shared reprogramming for clock_realtime and clock_monotonic |
| * |
| * 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 int hrtimer_reprogram(struct hrtimer *timer, |
| struct hrtimer_clock_base *base) |
| { |
| struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
| ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset); |
| int res; |
| |
| WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0); |
| |
| /* |
| * When the callback is running, we do not reprogram the clock event |
| * device. The timer callback is either running on a different CPU or |
| * the callback is executed in the hrtimer_interrupt context. The |
| * reprogramming is handled either by the softirq, which called the |
| * callback or at the end of the hrtimer_interrupt. |
| */ |
| if (hrtimer_callback_running(timer)) |
| return 0; |
| |
| /* |
| * CLOCK_REALTIME timer might be requested with an absolute |
| * expiry time which is less than base->offset. Nothing wrong |
| * about that, just avoid to call into the tick code, which |
| * has now objections against negative expiry values. |
| */ |
| if (expires.tv64 < 0) |
| return -ETIME; |
| |
| if (expires.tv64 >= cpu_base->expires_next.tv64) |
| return 0; |
| |
| /* |
| * 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 0; |
| |
| /* |
| * Clockevents returns -ETIME, when the event was in the past. |
| */ |
| res = tick_program_event(expires, 0); |
| if (!IS_ERR_VALUE(res)) |
| cpu_base->expires_next = expires; |
| return res; |
| } |
| |
| /* |
| * Initialize the high resolution related parts of cpu_base |
| */ |
| static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) |
| { |
| base->expires_next.tv64 = KTIME_MAX; |
| base->hres_active = 0; |
| } |
| |
| /* |
| * When High resolution timers are active, try to reprogram. Note, that in case |
| * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry |
| * check happens. The timer gets enqueued into the rbtree. The reprogramming |
| * and expiry check is done in the hrtimer_interrupt or in the softirq. |
| */ |
| static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, |
| struct hrtimer_clock_base *base) |
| { |
| return base->cpu_base->hres_active && hrtimer_reprogram(timer, base); |
| } |
| |
| 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(offs_real, offs_boot, offs_tai); |
| } |
| |
| /* |
| * 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 = &__get_cpu_var(hrtimer_bases); |
| |
| if (!hrtimer_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 int hrtimer_switch_to_hres(void) |
| { |
| int i, cpu = smp_processor_id(); |
| struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu); |
| unsigned long flags; |
| |
| if (base->hres_active) |
| return 1; |
| |
| local_irq_save(flags); |
| |
| if (tick_init_highres()) { |
| local_irq_restore(flags); |
| printk(KERN_WARNING "Could not switch to high resolution " |
| "mode on CPU %d\n", cpu); |
| return 0; |
| } |
| base->hres_active = 1; |
| for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) |
| base->clock_base[i].resolution = KTIME_HIGH_RES; |
| |
| tick_setup_sched_timer(); |
| /* "Retrigger" the interrupt to get things going */ |
| retrigger_next_event(NULL); |
| local_irq_restore(flags); |
| return 1; |
| } |
| |
| 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 reprogramm the hrtimer |
| * interrupt device on all cpus. |
| */ |
| void clock_was_set_delayed(void) |
| { |
| schedule_work(&hrtimer_work); |
| } |
| |
| #else |
| |
| static inline int hrtimer_hres_active(void) { return 0; } |
| static inline int hrtimer_is_hres_enabled(void) { return 0; } |
| static inline int hrtimer_switch_to_hres(void) { return 0; } |
| static inline void |
| hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { } |
| static inline int hrtimer_enqueue_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 the local CPU): |
| */ |
| 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(); |
| } |
| |
| static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) |
| { |
| #ifdef CONFIG_TIMER_STATS |
| if (timer->start_site) |
| return; |
| timer->start_site = __builtin_return_address(0); |
| memcpy(timer->start_comm, current->comm, TASK_COMM_LEN); |
| timer->start_pid = current->pid; |
| #endif |
| } |
| |
| static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer) |
| { |
| #ifdef CONFIG_TIMER_STATS |
| timer->start_site = NULL; |
| #endif |
| } |
| |
| static inline void timer_stats_account_hrtimer(struct hrtimer *timer) |
| { |
| #ifdef CONFIG_TIMER_STATS |
| if (likely(!timer_stats_active)) |
| return; |
| timer_stats_update_stats(timer, timer->start_pid, timer->start_site, |
| timer->function, timer->start_comm, 0); |
| #endif |
| } |
| |
| /* |
| * 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. |
| */ |
| 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.tv64 < 0) |
| return 0; |
| |
| if (interval.tv64 < timer->base->resolution.tv64) |
| interval.tv64 = timer->base->resolution.tv64; |
| |
| if (unlikely(delta.tv64 >= interval.tv64)) { |
| 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.tv64) |
| 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); |
| |
| 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 |
| * state of a possibly running callback. |
| */ |
| timer->state |= HRTIMER_STATE_ENQUEUED; |
| |
| return (&timer->node == base->active.next); |
| } |
| |
| /* |
| * __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, |
| unsigned long newstate, int reprogram) |
| { |
| struct timerqueue_node *next_timer; |
| if (!(timer->state & HRTIMER_STATE_ENQUEUED)) |
| goto out; |
| |
| next_timer = timerqueue_getnext(&base->active); |
| timerqueue_del(&base->active, &timer->node); |
| if (&timer->node == next_timer) { |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| /* Reprogram the clock event device. if enabled */ |
| if (reprogram && hrtimer_hres_active()) { |
| ktime_t expires; |
| |
| expires = ktime_sub(hrtimer_get_expires(timer), |
| base->offset); |
| if (base->cpu_base->expires_next.tv64 == expires.tv64) |
| hrtimer_force_reprogram(base->cpu_base, 1); |
| } |
| #endif |
| } |
| if (!timerqueue_getnext(&base->active)) |
| base->cpu_base->active_bases &= ~(1 << base->index); |
| out: |
| timer->state = newstate; |
| } |
| |
| /* |
| * remove hrtimer, called with base lock held |
| */ |
| static inline int |
| remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base) |
| { |
| if (hrtimer_is_queued(timer)) { |
| unsigned long 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); |
| timer_stats_hrtimer_clear_start_info(timer); |
| reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases); |
| /* |
| * We must preserve the CALLBACK state flag here, |
| * otherwise we could move the timer base in |
| * switch_hrtimer_base. |
| */ |
| state = timer->state & HRTIMER_STATE_CALLBACK; |
| __remove_hrtimer(timer, base, state, reprogram); |
| return 1; |
| } |
| return 0; |
| } |
| |
| int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
| unsigned long delta_ns, const enum hrtimer_mode mode, |
| int wakeup) |
| { |
| struct hrtimer_clock_base *base, *new_base; |
| unsigned long flags; |
| int ret, leftmost; |
| |
| base = lock_hrtimer_base(timer, &flags); |
| |
| /* Remove an active timer from the queue: */ |
| ret = remove_hrtimer(timer, base); |
| |
| if (mode & HRTIMER_MODE_REL) { |
| tim = ktime_add_safe(tim, base->get_time()); |
| /* |
| * CONFIG_TIME_LOW_RES is a temporary way for architectures |
| * to signal that they simply return xtime in |
| * do_gettimeoffset(). In this case we want to round up by |
| * resolution when starting a relative timer, to avoid short |
| * timeouts. This will go away with the GTOD framework. |
| */ |
| #ifdef CONFIG_TIME_LOW_RES |
| tim = ktime_add_safe(tim, base->resolution); |
| #endif |
| } |
| |
| 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); |
| |
| timer_stats_hrtimer_set_start_info(timer); |
| |
| leftmost = enqueue_hrtimer(timer, new_base); |
| |
| /* |
| * Only allow reprogramming if the new base is on this CPU. |
| * (it might still be on another CPU if the timer was pending) |
| * |
| * XXX send_remote_softirq() ? |
| */ |
| if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases) |
| && hrtimer_enqueue_reprogram(timer, new_base)) { |
| if (wakeup) { |
| /* |
| * We need to drop cpu_base->lock to avoid a |
| * lock ordering issue vs. rq->lock. |
| */ |
| raw_spin_unlock(&new_base->cpu_base->lock); |
| raise_softirq_irqoff(HRTIMER_SOFTIRQ); |
| local_irq_restore(flags); |
| return ret; |
| } else { |
| __raise_softirq_irqoff(HRTIMER_SOFTIRQ); |
| } |
| } |
| |
| unlock_hrtimer_base(timer, &flags); |
| |
| return ret; |
| } |
| |
| /** |
| * 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) |
| * |
| * Returns: |
| * 0 on success |
| * 1 when the timer was active |
| */ |
| int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
| unsigned long delta_ns, const enum hrtimer_mode mode) |
| { |
| return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1); |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_start_range_ns); |
| |
| /** |
| * hrtimer_start - (re)start an hrtimer on the current CPU |
| * @timer: the timer to be added |
| * @tim: expiry time |
| * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or |
| * relative (HRTIMER_MODE_REL) |
| * |
| * Returns: |
| * 0 on success |
| * 1 when the timer was active |
| */ |
| int |
| hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) |
| { |
| return __hrtimer_start_range_ns(timer, tim, 0, mode, 1); |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_start); |
| |
| |
| /** |
| * 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; |
| |
| base = lock_hrtimer_base(timer, &flags); |
| |
| if (!hrtimer_callback_running(timer)) |
| ret = remove_hrtimer(timer, base); |
| |
| 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 |
| */ |
| ktime_t hrtimer_get_remaining(const struct hrtimer *timer) |
| { |
| unsigned long flags; |
| ktime_t rem; |
| |
| lock_hrtimer_base(timer, &flags); |
| 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 delta to the next expiry event or KTIME_MAX if no timer |
| * is pending. |
| */ |
| ktime_t hrtimer_get_next_event(void) |
| { |
| struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
| struct hrtimer_clock_base *base = cpu_base->clock_base; |
| ktime_t delta, mindelta = { .tv64 = KTIME_MAX }; |
| unsigned long flags; |
| int i; |
| |
| raw_spin_lock_irqsave(&cpu_base->lock, flags); |
| |
| if (!hrtimer_hres_active()) { |
| for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { |
| struct hrtimer *timer; |
| struct timerqueue_node *next; |
| |
| next = timerqueue_getnext(&base->active); |
| if (!next) |
| continue; |
| |
| timer = container_of(next, struct hrtimer, node); |
| delta.tv64 = hrtimer_get_expires_tv64(timer); |
| delta = ktime_sub(delta, base->get_time()); |
| if (delta.tv64 < mindelta.tv64) |
| mindelta.tv64 = delta.tv64; |
| } |
| } |
| |
| raw_spin_unlock_irqrestore(&cpu_base->lock, flags); |
| |
| if (mindelta.tv64 < 0) |
| mindelta.tv64 = 0; |
| return mindelta; |
| } |
| #endif |
| |
| 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_get_cpu_var(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); |
| |
| #ifdef CONFIG_TIMER_STATS |
| timer->start_site = NULL; |
| timer->start_pid = -1; |
| memset(timer->start_comm, 0, TASK_COMM_LEN); |
| #endif |
| } |
| |
| /** |
| * 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); |
| |
| /** |
| * hrtimer_get_res - get the timer resolution for a clock |
| * @which_clock: which clock to query |
| * @tp: pointer to timespec variable to store the resolution |
| * |
| * Store the resolution of the clock selected by @which_clock in the |
| * variable pointed to by @tp. |
| */ |
| int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp) |
| { |
| struct hrtimer_cpu_base *cpu_base; |
| int base = hrtimer_clockid_to_base(which_clock); |
| |
| cpu_base = &__raw_get_cpu_var(hrtimer_bases); |
| *tp = ktime_to_timespec(cpu_base->clock_base[base].resolution); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(hrtimer_get_res); |
| |
| static void __run_hrtimer(struct hrtimer *timer, ktime_t *now) |
| { |
| struct hrtimer_clock_base *base = timer->base; |
| struct hrtimer_cpu_base *cpu_base = base->cpu_base; |
| enum hrtimer_restart (*fn)(struct hrtimer *); |
| int restart; |
| |
| WARN_ON(!irqs_disabled()); |
| |
| debug_deactivate(timer); |
| __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0); |
| timer_stats_account_hrtimer(timer); |
| fn = timer->function; |
| |
| /* |
| * 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 CALLBACK bit after enqueue_hrtimer and |
| * we do not reprogramm the event hardware. Happens either in |
| * hrtimer_start_range_ns() or in hrtimer_interrupt() |
| */ |
| if (restart != HRTIMER_NORESTART) { |
| BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); |
| enqueue_hrtimer(timer, base); |
| } |
| |
| WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK)); |
| |
| timer->state &= ~HRTIMER_STATE_CALLBACK; |
| } |
| |
| #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 = &__get_cpu_var(hrtimer_bases); |
| ktime_t expires_next, now, entry_time, delta; |
| int i, retries = 0; |
| |
| BUG_ON(!cpu_base->hres_active); |
| cpu_base->nr_events++; |
| dev->next_event.tv64 = KTIME_MAX; |
| |
| raw_spin_lock(&cpu_base->lock); |
| entry_time = now = hrtimer_update_base(cpu_base); |
| retry: |
| expires_next.tv64 = KTIME_MAX; |
| /* |
| * 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.tv64 = KTIME_MAX; |
| |
| for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { |
| 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))) { |
| 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.tv64 < hrtimer_get_softexpires_tv64(timer)) { |
| ktime_t expires; |
| |
| expires = ktime_sub(hrtimer_get_expires(timer), |
| base->offset); |
| if (expires.tv64 < 0) |
| expires.tv64 = KTIME_MAX; |
| if (expires.tv64 < expires_next.tv64) |
| expires_next = expires; |
| break; |
| } |
| |
| __run_hrtimer(timer, &basenow); |
| } |
| } |
| |
| /* |
| * Store the new expiry value so the migration code can verify |
| * against it. |
| */ |
| cpu_base->expires_next = expires_next; |
| raw_spin_unlock(&cpu_base->lock); |
| |
| /* Reprogramming necessary ? */ |
| if (expires_next.tv64 == KTIME_MAX || |
| !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 (delta.tv64 > cpu_base->max_hang_time.tv64) |
| cpu_base->max_hang_time = delta; |
| /* |
| * Limit it to a sensible value as we enforce a longer |
| * delay. Give the CPU at least 100ms to catch up. |
| */ |
| if (delta.tv64 > 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 void __hrtimer_peek_ahead_timers(void) |
| { |
| struct tick_device *td; |
| |
| if (!hrtimer_hres_active()) |
| return; |
| |
| td = &__get_cpu_var(tick_cpu_device); |
| if (td && td->evtdev) |
| hrtimer_interrupt(td->evtdev); |
| } |
| |
| /** |
| * hrtimer_peek_ahead_timers -- run soft-expired timers now |
| * |
| * hrtimer_peek_ahead_timers will peek at the timer queue of |
| * the current cpu and check if there are any timers for which |
| * the soft expires time has passed. If any such timers exist, |
| * they are run immediately and then removed from the timer queue. |
| * |
| */ |
| void hrtimer_peek_ahead_timers(void) |
| { |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| __hrtimer_peek_ahead_timers(); |
| local_irq_restore(flags); |
| } |
| |
| static void run_hrtimer_softirq(struct softirq_action *h) |
| { |
| hrtimer_peek_ahead_timers(); |
| } |
| |
| #else /* CONFIG_HIGH_RES_TIMERS */ |
| |
| static inline void __hrtimer_peek_ahead_timers(void) { } |
| |
| #endif /* !CONFIG_HIGH_RES_TIMERS */ |
| |
| /* |
| * Called from timer softirq every jiffy, expire hrtimers: |
| * |
| * For HRT its the fall back code to run the softirq in the timer |
| * softirq context in case the hrtimer initialization failed or has |
| * not been done yet. |
| */ |
| void hrtimer_run_pending(void) |
| { |
| if (hrtimer_hres_active()) |
| return; |
| |
| /* |
| * This _is_ ugly: We have to check in the softirq context, |
| * whether we can switch to highres and / or nohz mode. The |
| * clocksource switch happens in the timer interrupt 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(); |
| } |
| |
| /* |
| * Called from hardirq context every jiffy |
| */ |
| void hrtimer_run_queues(void) |
| { |
| struct timerqueue_node *node; |
| struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
| struct hrtimer_clock_base *base; |
| int index, gettime = 1; |
| |
| if (hrtimer_hres_active()) |
| return; |
| |
| for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) { |
| base = &cpu_base->clock_base[index]; |
| if (!timerqueue_getnext(&base->active)) |
| continue; |
| |
| if (gettime) { |
| hrtimer_get_softirq_time(cpu_base); |
| gettime = 0; |
| } |
| |
| raw_spin_lock(&cpu_base->lock); |
| |
| while ((node = timerqueue_getnext(&base->active))) { |
| struct hrtimer *timer; |
| |
| timer = container_of(node, struct hrtimer, node); |
| if (base->softirq_time.tv64 <= |
| hrtimer_get_expires_tv64(timer)) |
| break; |
| |
| __run_hrtimer(timer, &base->softirq_time); |
| } |
| 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 (!hrtimer_active(&t->timer)) |
| t->task = NULL; |
| |
| if (likely(t->task)) |
| 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.tv64 <= 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; |
| unsigned long slack; |
| |
| slack = current->timer_slack_ns; |
| if (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_thread_info()->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: |
| */ |
| static void __cpuinit init_hrtimers_cpu(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); |
| } |
| |
| hrtimer_init_hres(cpu_base); |
| } |
| |
| #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 STATE_MIGRATE 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_MIGRATE, 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); |
| |
| /* Clear the migration state bit */ |
| timer->state &= ~HRTIMER_STATE_MIGRATE; |
| } |
| } |
| |
| static void migrate_hrtimers(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 = &__get_cpu_var(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(); |
| } |
| |
| #endif /* CONFIG_HOTPLUG_CPU */ |
| |
| static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self, |
| unsigned long action, void *hcpu) |
| { |
| int scpu = (long)hcpu; |
| |
| switch (action) { |
| |
| case CPU_UP_PREPARE: |
| case CPU_UP_PREPARE_FROZEN: |
| init_hrtimers_cpu(scpu); |
| break; |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| case CPU_DYING: |
| case CPU_DYING_FROZEN: |
| clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu); |
| break; |
| case CPU_DEAD: |
| case CPU_DEAD_FROZEN: |
| { |
| clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu); |
| migrate_hrtimers(scpu); |
| break; |
| } |
| #endif |
| |
| default: |
| break; |
| } |
| |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block __cpuinitdata hrtimers_nb = { |
| .notifier_call = hrtimer_cpu_notify, |
| }; |
| |
| void __init hrtimers_init(void) |
| { |
| hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE, |
| (void *)(long)smp_processor_id()); |
| register_cpu_notifier(&hrtimers_nb); |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq); |
| #endif |
| } |
| |
| /** |
| * 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, unsigned long 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->tv64) { |
| __set_current_state(TASK_RUNNING); |
| return 0; |
| } |
| |
| /* |
| * A NULL parameter means "infinite" |
| */ |
| if (!expires) { |
| schedule(); |
| __set_current_state(TASK_RUNNING); |
| 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 (!hrtimer_active(&t.timer)) |
| t.task = NULL; |
| |
| 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. |
| * |
| * %TASK_INTERRUPTIBLE - the routine may return early if a signal is |
| * delivered to the current task. |
| * |
| * The current task state is guaranteed to be TASK_RUNNING when this |
| * routine returns. |
| * |
| * Returns 0 when the timer has expired otherwise -EINTR |
| */ |
| int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long 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. |
| * |
| * %TASK_INTERRUPTIBLE - the routine may return early if a signal is |
| * delivered to the current task. |
| * |
| * The current task state is guaranteed to be TASK_RUNNING when this |
| * routine returns. |
| * |
| * Returns 0 when the timer has expired otherwise -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); |