| /* |
| * linux/kernel/timer.c |
| * |
| * Kernel internal timers |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better. |
| * |
| * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 |
| * "A Kernel Model for Precision Timekeeping" by Dave Mills |
| * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to |
| * serialize accesses to xtime/lost_ticks). |
| * Copyright (C) 1998 Andrea Arcangeli |
| * 1999-03-10 Improved NTP compatibility by Ulrich Windl |
| * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love |
| * 2000-10-05 Implemented scalable SMP per-CPU timer handling. |
| * Copyright (C) 2000, 2001, 2002 Ingo Molnar |
| * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar |
| */ |
| |
| #include <linux/kernel_stat.h> |
| #include <linux/export.h> |
| #include <linux/interrupt.h> |
| #include <linux/percpu.h> |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/swap.h> |
| #include <linux/pid_namespace.h> |
| #include <linux/notifier.h> |
| #include <linux/thread_info.h> |
| #include <linux/time.h> |
| #include <linux/jiffies.h> |
| #include <linux/posix-timers.h> |
| #include <linux/cpu.h> |
| #include <linux/syscalls.h> |
| #include <linux/delay.h> |
| #include <linux/tick.h> |
| #include <linux/kallsyms.h> |
| #include <linux/irq_work.h> |
| #include <linux/sched.h> |
| #include <linux/sched/sysctl.h> |
| #include <linux/slab.h> |
| #include <linux/compat.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/unistd.h> |
| #include <asm/div64.h> |
| #include <asm/timex.h> |
| #include <asm/io.h> |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/timer.h> |
| |
| __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; |
| |
| EXPORT_SYMBOL(jiffies_64); |
| |
| /* |
| * per-CPU timer vector definitions: |
| */ |
| #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6) |
| #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8) |
| #define TVN_SIZE (1 << TVN_BITS) |
| #define TVR_SIZE (1 << TVR_BITS) |
| #define TVN_MASK (TVN_SIZE - 1) |
| #define TVR_MASK (TVR_SIZE - 1) |
| #define MAX_TVAL ((unsigned long)((1ULL << (TVR_BITS + 4*TVN_BITS)) - 1)) |
| |
| struct tvec { |
| struct list_head vec[TVN_SIZE]; |
| }; |
| |
| struct tvec_root { |
| struct list_head vec[TVR_SIZE]; |
| }; |
| |
| struct tvec_base { |
| spinlock_t lock; |
| struct timer_list *running_timer; |
| unsigned long timer_jiffies; |
| unsigned long next_timer; |
| unsigned long active_timers; |
| unsigned long all_timers; |
| int cpu; |
| struct tvec_root tv1; |
| struct tvec tv2; |
| struct tvec tv3; |
| struct tvec tv4; |
| struct tvec tv5; |
| } ____cacheline_aligned; |
| |
| struct tvec_base boot_tvec_bases; |
| EXPORT_SYMBOL(boot_tvec_bases); |
| static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases; |
| |
| /* Functions below help us manage 'deferrable' flag */ |
| static inline unsigned int tbase_get_deferrable(struct tvec_base *base) |
| { |
| return ((unsigned int)(unsigned long)base & TIMER_DEFERRABLE); |
| } |
| |
| static inline unsigned int tbase_get_irqsafe(struct tvec_base *base) |
| { |
| return ((unsigned int)(unsigned long)base & TIMER_IRQSAFE); |
| } |
| |
| static inline struct tvec_base *tbase_get_base(struct tvec_base *base) |
| { |
| return ((struct tvec_base *)((unsigned long)base & ~TIMER_FLAG_MASK)); |
| } |
| |
| static inline void |
| timer_set_base(struct timer_list *timer, struct tvec_base *new_base) |
| { |
| unsigned long flags = (unsigned long)timer->base & TIMER_FLAG_MASK; |
| |
| timer->base = (struct tvec_base *)((unsigned long)(new_base) | flags); |
| } |
| |
| static unsigned long round_jiffies_common(unsigned long j, int cpu, |
| bool force_up) |
| { |
| int rem; |
| unsigned long original = j; |
| |
| /* |
| * We don't want all cpus firing their timers at once hitting the |
| * same lock or cachelines, so we skew each extra cpu with an extra |
| * 3 jiffies. This 3 jiffies came originally from the mm/ code which |
| * already did this. |
| * The skew is done by adding 3*cpunr, then round, then subtract this |
| * extra offset again. |
| */ |
| j += cpu * 3; |
| |
| rem = j % HZ; |
| |
| /* |
| * If the target jiffie is just after a whole second (which can happen |
| * due to delays of the timer irq, long irq off times etc etc) then |
| * we should round down to the whole second, not up. Use 1/4th second |
| * as cutoff for this rounding as an extreme upper bound for this. |
| * But never round down if @force_up is set. |
| */ |
| if (rem < HZ/4 && !force_up) /* round down */ |
| j = j - rem; |
| else /* round up */ |
| j = j - rem + HZ; |
| |
| /* now that we have rounded, subtract the extra skew again */ |
| j -= cpu * 3; |
| |
| /* |
| * Make sure j is still in the future. Otherwise return the |
| * unmodified value. |
| */ |
| return time_is_after_jiffies(j) ? j : original; |
| } |
| |
| /** |
| * __round_jiffies - function to round jiffies to a full second |
| * @j: the time in (absolute) jiffies that should be rounded |
| * @cpu: the processor number on which the timeout will happen |
| * |
| * __round_jiffies() rounds an absolute time in the future (in jiffies) |
| * up or down to (approximately) full seconds. This is useful for timers |
| * for which the exact time they fire does not matter too much, as long as |
| * they fire approximately every X seconds. |
| * |
| * By rounding these timers to whole seconds, all such timers will fire |
| * at the same time, rather than at various times spread out. The goal |
| * of this is to have the CPU wake up less, which saves power. |
| * |
| * The exact rounding is skewed for each processor to avoid all |
| * processors firing at the exact same time, which could lead |
| * to lock contention or spurious cache line bouncing. |
| * |
| * The return value is the rounded version of the @j parameter. |
| */ |
| unsigned long __round_jiffies(unsigned long j, int cpu) |
| { |
| return round_jiffies_common(j, cpu, false); |
| } |
| EXPORT_SYMBOL_GPL(__round_jiffies); |
| |
| /** |
| * __round_jiffies_relative - function to round jiffies to a full second |
| * @j: the time in (relative) jiffies that should be rounded |
| * @cpu: the processor number on which the timeout will happen |
| * |
| * __round_jiffies_relative() rounds a time delta in the future (in jiffies) |
| * up or down to (approximately) full seconds. This is useful for timers |
| * for which the exact time they fire does not matter too much, as long as |
| * they fire approximately every X seconds. |
| * |
| * By rounding these timers to whole seconds, all such timers will fire |
| * at the same time, rather than at various times spread out. The goal |
| * of this is to have the CPU wake up less, which saves power. |
| * |
| * The exact rounding is skewed for each processor to avoid all |
| * processors firing at the exact same time, which could lead |
| * to lock contention or spurious cache line bouncing. |
| * |
| * The return value is the rounded version of the @j parameter. |
| */ |
| unsigned long __round_jiffies_relative(unsigned long j, int cpu) |
| { |
| unsigned long j0 = jiffies; |
| |
| /* Use j0 because jiffies might change while we run */ |
| return round_jiffies_common(j + j0, cpu, false) - j0; |
| } |
| EXPORT_SYMBOL_GPL(__round_jiffies_relative); |
| |
| /** |
| * round_jiffies - function to round jiffies to a full second |
| * @j: the time in (absolute) jiffies that should be rounded |
| * |
| * round_jiffies() rounds an absolute time in the future (in jiffies) |
| * up or down to (approximately) full seconds. This is useful for timers |
| * for which the exact time they fire does not matter too much, as long as |
| * they fire approximately every X seconds. |
| * |
| * By rounding these timers to whole seconds, all such timers will fire |
| * at the same time, rather than at various times spread out. The goal |
| * of this is to have the CPU wake up less, which saves power. |
| * |
| * The return value is the rounded version of the @j parameter. |
| */ |
| unsigned long round_jiffies(unsigned long j) |
| { |
| return round_jiffies_common(j, raw_smp_processor_id(), false); |
| } |
| EXPORT_SYMBOL_GPL(round_jiffies); |
| |
| /** |
| * round_jiffies_relative - function to round jiffies to a full second |
| * @j: the time in (relative) jiffies that should be rounded |
| * |
| * round_jiffies_relative() rounds a time delta in the future (in jiffies) |
| * up or down to (approximately) full seconds. This is useful for timers |
| * for which the exact time they fire does not matter too much, as long as |
| * they fire approximately every X seconds. |
| * |
| * By rounding these timers to whole seconds, all such timers will fire |
| * at the same time, rather than at various times spread out. The goal |
| * of this is to have the CPU wake up less, which saves power. |
| * |
| * The return value is the rounded version of the @j parameter. |
| */ |
| unsigned long round_jiffies_relative(unsigned long j) |
| { |
| return __round_jiffies_relative(j, raw_smp_processor_id()); |
| } |
| EXPORT_SYMBOL_GPL(round_jiffies_relative); |
| |
| /** |
| * __round_jiffies_up - function to round jiffies up to a full second |
| * @j: the time in (absolute) jiffies that should be rounded |
| * @cpu: the processor number on which the timeout will happen |
| * |
| * This is the same as __round_jiffies() except that it will never |
| * round down. This is useful for timeouts for which the exact time |
| * of firing does not matter too much, as long as they don't fire too |
| * early. |
| */ |
| unsigned long __round_jiffies_up(unsigned long j, int cpu) |
| { |
| return round_jiffies_common(j, cpu, true); |
| } |
| EXPORT_SYMBOL_GPL(__round_jiffies_up); |
| |
| /** |
| * __round_jiffies_up_relative - function to round jiffies up to a full second |
| * @j: the time in (relative) jiffies that should be rounded |
| * @cpu: the processor number on which the timeout will happen |
| * |
| * This is the same as __round_jiffies_relative() except that it will never |
| * round down. This is useful for timeouts for which the exact time |
| * of firing does not matter too much, as long as they don't fire too |
| * early. |
| */ |
| unsigned long __round_jiffies_up_relative(unsigned long j, int cpu) |
| { |
| unsigned long j0 = jiffies; |
| |
| /* Use j0 because jiffies might change while we run */ |
| return round_jiffies_common(j + j0, cpu, true) - j0; |
| } |
| EXPORT_SYMBOL_GPL(__round_jiffies_up_relative); |
| |
| /** |
| * round_jiffies_up - function to round jiffies up to a full second |
| * @j: the time in (absolute) jiffies that should be rounded |
| * |
| * This is the same as round_jiffies() except that it will never |
| * round down. This is useful for timeouts for which the exact time |
| * of firing does not matter too much, as long as they don't fire too |
| * early. |
| */ |
| unsigned long round_jiffies_up(unsigned long j) |
| { |
| return round_jiffies_common(j, raw_smp_processor_id(), true); |
| } |
| EXPORT_SYMBOL_GPL(round_jiffies_up); |
| |
| /** |
| * round_jiffies_up_relative - function to round jiffies up to a full second |
| * @j: the time in (relative) jiffies that should be rounded |
| * |
| * This is the same as round_jiffies_relative() except that it will never |
| * round down. This is useful for timeouts for which the exact time |
| * of firing does not matter too much, as long as they don't fire too |
| * early. |
| */ |
| unsigned long round_jiffies_up_relative(unsigned long j) |
| { |
| return __round_jiffies_up_relative(j, raw_smp_processor_id()); |
| } |
| EXPORT_SYMBOL_GPL(round_jiffies_up_relative); |
| |
| /** |
| * set_timer_slack - set the allowed slack for a timer |
| * @timer: the timer to be modified |
| * @slack_hz: the amount of time (in jiffies) allowed for rounding |
| * |
| * Set the amount of time, in jiffies, that a certain timer has |
| * in terms of slack. By setting this value, the timer subsystem |
| * will schedule the actual timer somewhere between |
| * the time mod_timer() asks for, and that time plus the slack. |
| * |
| * By setting the slack to -1, a percentage of the delay is used |
| * instead. |
| */ |
| void set_timer_slack(struct timer_list *timer, int slack_hz) |
| { |
| timer->slack = slack_hz; |
| } |
| EXPORT_SYMBOL_GPL(set_timer_slack); |
| |
| /* |
| * If the list is empty, catch up ->timer_jiffies to the current time. |
| * The caller must hold the tvec_base lock. Returns true if the list |
| * was empty and therefore ->timer_jiffies was updated. |
| */ |
| static bool catchup_timer_jiffies(struct tvec_base *base) |
| { |
| if (!base->all_timers) { |
| base->timer_jiffies = jiffies; |
| return true; |
| } |
| return false; |
| } |
| |
| static void |
| __internal_add_timer(struct tvec_base *base, struct timer_list *timer) |
| { |
| unsigned long expires = timer->expires; |
| unsigned long idx = expires - base->timer_jiffies; |
| struct list_head *vec; |
| |
| if (idx < TVR_SIZE) { |
| int i = expires & TVR_MASK; |
| vec = base->tv1.vec + i; |
| } else if (idx < 1 << (TVR_BITS + TVN_BITS)) { |
| int i = (expires >> TVR_BITS) & TVN_MASK; |
| vec = base->tv2.vec + i; |
| } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) { |
| int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK; |
| vec = base->tv3.vec + i; |
| } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) { |
| int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK; |
| vec = base->tv4.vec + i; |
| } else if ((signed long) idx < 0) { |
| /* |
| * Can happen if you add a timer with expires == jiffies, |
| * or you set a timer to go off in the past |
| */ |
| vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK); |
| } else { |
| int i; |
| /* If the timeout is larger than MAX_TVAL (on 64-bit |
| * architectures or with CONFIG_BASE_SMALL=1) then we |
| * use the maximum timeout. |
| */ |
| if (idx > MAX_TVAL) { |
| idx = MAX_TVAL; |
| expires = idx + base->timer_jiffies; |
| } |
| i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK; |
| vec = base->tv5.vec + i; |
| } |
| /* |
| * Timers are FIFO: |
| */ |
| list_add_tail(&timer->entry, vec); |
| } |
| |
| static void internal_add_timer(struct tvec_base *base, struct timer_list *timer) |
| { |
| (void)catchup_timer_jiffies(base); |
| __internal_add_timer(base, timer); |
| /* |
| * Update base->active_timers and base->next_timer |
| */ |
| if (!tbase_get_deferrable(timer->base)) { |
| if (!base->active_timers++ || |
| time_before(timer->expires, base->next_timer)) |
| base->next_timer = timer->expires; |
| } |
| base->all_timers++; |
| |
| /* |
| * Check whether the other CPU is in dynticks mode and needs |
| * to be triggered to reevaluate the timer wheel. |
| * We are protected against the other CPU fiddling |
| * with the timer by holding the timer base lock. This also |
| * makes sure that a CPU on the way to stop its tick can not |
| * evaluate the timer wheel. |
| * |
| * Spare the IPI for deferrable timers on idle targets though. |
| * The next busy ticks will take care of it. Except full dynticks |
| * require special care against races with idle_cpu(), lets deal |
| * with that later. |
| */ |
| if (!tbase_get_deferrable(base) || tick_nohz_full_cpu(base->cpu)) |
| wake_up_nohz_cpu(base->cpu); |
| } |
| |
| #ifdef CONFIG_TIMER_STATS |
| void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr) |
| { |
| if (timer->start_site) |
| return; |
| |
| timer->start_site = addr; |
| memcpy(timer->start_comm, current->comm, TASK_COMM_LEN); |
| timer->start_pid = current->pid; |
| } |
| |
| static void timer_stats_account_timer(struct timer_list *timer) |
| { |
| unsigned int flag = 0; |
| |
| if (likely(!timer->start_site)) |
| return; |
| if (unlikely(tbase_get_deferrable(timer->base))) |
| flag |= TIMER_STATS_FLAG_DEFERRABLE; |
| |
| timer_stats_update_stats(timer, timer->start_pid, timer->start_site, |
| timer->function, timer->start_comm, flag); |
| } |
| |
| #else |
| static void timer_stats_account_timer(struct timer_list *timer) {} |
| #endif |
| |
| #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
| |
| static struct debug_obj_descr timer_debug_descr; |
| |
| static void *timer_debug_hint(void *addr) |
| { |
| return ((struct timer_list *) addr)->function; |
| } |
| |
| /* |
| * fixup_init is called when: |
| * - an active object is initialized |
| */ |
| static int timer_fixup_init(void *addr, enum debug_obj_state state) |
| { |
| struct timer_list *timer = addr; |
| |
| switch (state) { |
| case ODEBUG_STATE_ACTIVE: |
| del_timer_sync(timer); |
| debug_object_init(timer, &timer_debug_descr); |
| return 1; |
| default: |
| return 0; |
| } |
| } |
| |
| /* Stub timer callback for improperly used timers. */ |
| static void stub_timer(unsigned long data) |
| { |
| WARN_ON(1); |
| } |
| |
| /* |
| * fixup_activate is called when: |
| * - an active object is activated |
| * - an unknown object is activated (might be a statically initialized object) |
| */ |
| static int timer_fixup_activate(void *addr, enum debug_obj_state state) |
| { |
| struct timer_list *timer = addr; |
| |
| switch (state) { |
| |
| case ODEBUG_STATE_NOTAVAILABLE: |
| /* |
| * This is not really a fixup. The timer was |
| * statically initialized. We just make sure that it |
| * is tracked in the object tracker. |
| */ |
| if (timer->entry.next == NULL && |
| timer->entry.prev == TIMER_ENTRY_STATIC) { |
| debug_object_init(timer, &timer_debug_descr); |
| debug_object_activate(timer, &timer_debug_descr); |
| return 0; |
| } else { |
| setup_timer(timer, stub_timer, 0); |
| return 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 timer_fixup_free(void *addr, enum debug_obj_state state) |
| { |
| struct timer_list *timer = addr; |
| |
| switch (state) { |
| case ODEBUG_STATE_ACTIVE: |
| del_timer_sync(timer); |
| debug_object_free(timer, &timer_debug_descr); |
| return 1; |
| default: |
| return 0; |
| } |
| } |
| |
| /* |
| * fixup_assert_init is called when: |
| * - an untracked/uninit-ed object is found |
| */ |
| static int timer_fixup_assert_init(void *addr, enum debug_obj_state state) |
| { |
| struct timer_list *timer = addr; |
| |
| switch (state) { |
| case ODEBUG_STATE_NOTAVAILABLE: |
| if (timer->entry.prev == TIMER_ENTRY_STATIC) { |
| /* |
| * This is not really a fixup. The timer was |
| * statically initialized. We just make sure that it |
| * is tracked in the object tracker. |
| */ |
| debug_object_init(timer, &timer_debug_descr); |
| return 0; |
| } else { |
| setup_timer(timer, stub_timer, 0); |
| return 1; |
| } |
| default: |
| return 0; |
| } |
| } |
| |
| static struct debug_obj_descr timer_debug_descr = { |
| .name = "timer_list", |
| .debug_hint = timer_debug_hint, |
| .fixup_init = timer_fixup_init, |
| .fixup_activate = timer_fixup_activate, |
| .fixup_free = timer_fixup_free, |
| .fixup_assert_init = timer_fixup_assert_init, |
| }; |
| |
| static inline void debug_timer_init(struct timer_list *timer) |
| { |
| debug_object_init(timer, &timer_debug_descr); |
| } |
| |
| static inline void debug_timer_activate(struct timer_list *timer) |
| { |
| debug_object_activate(timer, &timer_debug_descr); |
| } |
| |
| static inline void debug_timer_deactivate(struct timer_list *timer) |
| { |
| debug_object_deactivate(timer, &timer_debug_descr); |
| } |
| |
| static inline void debug_timer_free(struct timer_list *timer) |
| { |
| debug_object_free(timer, &timer_debug_descr); |
| } |
| |
| static inline void debug_timer_assert_init(struct timer_list *timer) |
| { |
| debug_object_assert_init(timer, &timer_debug_descr); |
| } |
| |
| static void do_init_timer(struct timer_list *timer, unsigned int flags, |
| const char *name, struct lock_class_key *key); |
| |
| void init_timer_on_stack_key(struct timer_list *timer, unsigned int flags, |
| const char *name, struct lock_class_key *key) |
| { |
| debug_object_init_on_stack(timer, &timer_debug_descr); |
| do_init_timer(timer, flags, name, key); |
| } |
| EXPORT_SYMBOL_GPL(init_timer_on_stack_key); |
| |
| void destroy_timer_on_stack(struct timer_list *timer) |
| { |
| debug_object_free(timer, &timer_debug_descr); |
| } |
| EXPORT_SYMBOL_GPL(destroy_timer_on_stack); |
| |
| #else |
| static inline void debug_timer_init(struct timer_list *timer) { } |
| static inline void debug_timer_activate(struct timer_list *timer) { } |
| static inline void debug_timer_deactivate(struct timer_list *timer) { } |
| static inline void debug_timer_assert_init(struct timer_list *timer) { } |
| #endif |
| |
| static inline void debug_init(struct timer_list *timer) |
| { |
| debug_timer_init(timer); |
| trace_timer_init(timer); |
| } |
| |
| static inline void |
| debug_activate(struct timer_list *timer, unsigned long expires) |
| { |
| debug_timer_activate(timer); |
| trace_timer_start(timer, expires); |
| } |
| |
| static inline void debug_deactivate(struct timer_list *timer) |
| { |
| debug_timer_deactivate(timer); |
| trace_timer_cancel(timer); |
| } |
| |
| static inline void debug_assert_init(struct timer_list *timer) |
| { |
| debug_timer_assert_init(timer); |
| } |
| |
| static void do_init_timer(struct timer_list *timer, unsigned int flags, |
| const char *name, struct lock_class_key *key) |
| { |
| struct tvec_base *base = raw_cpu_read(tvec_bases); |
| |
| timer->entry.next = NULL; |
| timer->base = (void *)((unsigned long)base | flags); |
| timer->slack = -1; |
| #ifdef CONFIG_TIMER_STATS |
| timer->start_site = NULL; |
| timer->start_pid = -1; |
| memset(timer->start_comm, 0, TASK_COMM_LEN); |
| #endif |
| lockdep_init_map(&timer->lockdep_map, name, key, 0); |
| } |
| |
| /** |
| * init_timer_key - initialize a timer |
| * @timer: the timer to be initialized |
| * @flags: timer flags |
| * @name: name of the timer |
| * @key: lockdep class key of the fake lock used for tracking timer |
| * sync lock dependencies |
| * |
| * init_timer_key() must be done to a timer prior calling *any* of the |
| * other timer functions. |
| */ |
| void init_timer_key(struct timer_list *timer, unsigned int flags, |
| const char *name, struct lock_class_key *key) |
| { |
| debug_init(timer); |
| do_init_timer(timer, flags, name, key); |
| } |
| EXPORT_SYMBOL(init_timer_key); |
| |
| static inline void detach_timer(struct timer_list *timer, bool clear_pending) |
| { |
| struct list_head *entry = &timer->entry; |
| |
| debug_deactivate(timer); |
| |
| __list_del(entry->prev, entry->next); |
| if (clear_pending) |
| entry->next = NULL; |
| entry->prev = LIST_POISON2; |
| } |
| |
| static inline void |
| detach_expired_timer(struct timer_list *timer, struct tvec_base *base) |
| { |
| detach_timer(timer, true); |
| if (!tbase_get_deferrable(timer->base)) |
| base->active_timers--; |
| base->all_timers--; |
| (void)catchup_timer_jiffies(base); |
| } |
| |
| static int detach_if_pending(struct timer_list *timer, struct tvec_base *base, |
| bool clear_pending) |
| { |
| if (!timer_pending(timer)) |
| return 0; |
| |
| detach_timer(timer, clear_pending); |
| if (!tbase_get_deferrable(timer->base)) { |
| base->active_timers--; |
| if (timer->expires == base->next_timer) |
| base->next_timer = base->timer_jiffies; |
| } |
| base->all_timers--; |
| (void)catchup_timer_jiffies(base); |
| return 1; |
| } |
| |
| /* |
| * We are using hashed locking: holding per_cpu(tvec_bases).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 ->tvX lists. |
| * |
| * 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 tvec_base *lock_timer_base(struct timer_list *timer, |
| unsigned long *flags) |
| __acquires(timer->base->lock) |
| { |
| struct tvec_base *base; |
| |
| for (;;) { |
| struct tvec_base *prelock_base = timer->base; |
| base = tbase_get_base(prelock_base); |
| if (likely(base != NULL)) { |
| spin_lock_irqsave(&base->lock, *flags); |
| if (likely(prelock_base == timer->base)) |
| return base; |
| /* The timer has migrated to another CPU */ |
| spin_unlock_irqrestore(&base->lock, *flags); |
| } |
| cpu_relax(); |
| } |
| } |
| |
| static inline int |
| __mod_timer(struct timer_list *timer, unsigned long expires, |
| bool pending_only, int pinned) |
| { |
| struct tvec_base *base, *new_base; |
| unsigned long flags; |
| int ret = 0 , cpu; |
| |
| timer_stats_timer_set_start_info(timer); |
| BUG_ON(!timer->function); |
| |
| base = lock_timer_base(timer, &flags); |
| |
| ret = detach_if_pending(timer, base, false); |
| if (!ret && pending_only) |
| goto out_unlock; |
| |
| debug_activate(timer, expires); |
| |
| cpu = get_nohz_timer_target(pinned); |
| new_base = per_cpu(tvec_bases, cpu); |
| |
| if (base != new_base) { |
| /* |
| * We are trying to schedule the timer on the local CPU. |
| * However we can't change timer's base while it is running, |
| * otherwise del_timer_sync() can't detect that the timer's |
| * handler yet has not finished. This also guarantees that |
| * the timer is serialized wrt itself. |
| */ |
| if (likely(base->running_timer != timer)) { |
| /* See the comment in lock_timer_base() */ |
| timer_set_base(timer, NULL); |
| spin_unlock(&base->lock); |
| base = new_base; |
| spin_lock(&base->lock); |
| timer_set_base(timer, base); |
| } |
| } |
| |
| timer->expires = expires; |
| internal_add_timer(base, timer); |
| |
| out_unlock: |
| spin_unlock_irqrestore(&base->lock, flags); |
| |
| return ret; |
| } |
| |
| /** |
| * mod_timer_pending - modify a pending timer's timeout |
| * @timer: the pending timer to be modified |
| * @expires: new timeout in jiffies |
| * |
| * mod_timer_pending() is the same for pending timers as mod_timer(), |
| * but will not re-activate and modify already deleted timers. |
| * |
| * It is useful for unserialized use of timers. |
| */ |
| int mod_timer_pending(struct timer_list *timer, unsigned long expires) |
| { |
| return __mod_timer(timer, expires, true, TIMER_NOT_PINNED); |
| } |
| EXPORT_SYMBOL(mod_timer_pending); |
| |
| /* |
| * Decide where to put the timer while taking the slack into account |
| * |
| * Algorithm: |
| * 1) calculate the maximum (absolute) time |
| * 2) calculate the highest bit where the expires and new max are different |
| * 3) use this bit to make a mask |
| * 4) use the bitmask to round down the maximum time, so that all last |
| * bits are zeros |
| */ |
| static inline |
| unsigned long apply_slack(struct timer_list *timer, unsigned long expires) |
| { |
| unsigned long expires_limit, mask; |
| int bit; |
| |
| if (timer->slack >= 0) { |
| expires_limit = expires + timer->slack; |
| } else { |
| long delta = expires - jiffies; |
| |
| if (delta < 256) |
| return expires; |
| |
| expires_limit = expires + delta / 256; |
| } |
| mask = expires ^ expires_limit; |
| if (mask == 0) |
| return expires; |
| |
| bit = find_last_bit(&mask, BITS_PER_LONG); |
| |
| mask = (1UL << bit) - 1; |
| |
| expires_limit = expires_limit & ~(mask); |
| |
| return expires_limit; |
| } |
| |
| /** |
| * mod_timer - modify a timer's timeout |
| * @timer: the timer to be modified |
| * @expires: new timeout in jiffies |
| * |
| * mod_timer() is a more efficient way to update the expire field of an |
| * active timer (if the timer is inactive it will be activated) |
| * |
| * mod_timer(timer, expires) is equivalent to: |
| * |
| * del_timer(timer); timer->expires = expires; add_timer(timer); |
| * |
| * Note that if there are multiple unserialized concurrent users of the |
| * same timer, then mod_timer() is the only safe way to modify the timeout, |
| * since add_timer() cannot modify an already running timer. |
| * |
| * The function returns whether it has modified a pending timer or not. |
| * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an |
| * active timer returns 1.) |
| */ |
| int mod_timer(struct timer_list *timer, unsigned long expires) |
| { |
| expires = apply_slack(timer, expires); |
| |
| /* |
| * This is a common optimization triggered by the |
| * networking code - if the timer is re-modified |
| * to be the same thing then just return: |
| */ |
| if (timer_pending(timer) && timer->expires == expires) |
| return 1; |
| |
| return __mod_timer(timer, expires, false, TIMER_NOT_PINNED); |
| } |
| EXPORT_SYMBOL(mod_timer); |
| |
| /** |
| * mod_timer_pinned - modify a timer's timeout |
| * @timer: the timer to be modified |
| * @expires: new timeout in jiffies |
| * |
| * mod_timer_pinned() is a way to update the expire field of an |
| * active timer (if the timer is inactive it will be activated) |
| * and to ensure that the timer is scheduled on the current CPU. |
| * |
| * Note that this does not prevent the timer from being migrated |
| * when the current CPU goes offline. If this is a problem for |
| * you, use CPU-hotplug notifiers to handle it correctly, for |
| * example, cancelling the timer when the corresponding CPU goes |
| * offline. |
| * |
| * mod_timer_pinned(timer, expires) is equivalent to: |
| * |
| * del_timer(timer); timer->expires = expires; add_timer(timer); |
| */ |
| int mod_timer_pinned(struct timer_list *timer, unsigned long expires) |
| { |
| if (timer->expires == expires && timer_pending(timer)) |
| return 1; |
| |
| return __mod_timer(timer, expires, false, TIMER_PINNED); |
| } |
| EXPORT_SYMBOL(mod_timer_pinned); |
| |
| /** |
| * add_timer - start a timer |
| * @timer: the timer to be added |
| * |
| * The kernel will do a ->function(->data) callback from the |
| * timer interrupt at the ->expires point in the future. The |
| * current time is 'jiffies'. |
| * |
| * The timer's ->expires, ->function (and if the handler uses it, ->data) |
| * fields must be set prior calling this function. |
| * |
| * Timers with an ->expires field in the past will be executed in the next |
| * timer tick. |
| */ |
| void add_timer(struct timer_list *timer) |
| { |
| BUG_ON(timer_pending(timer)); |
| mod_timer(timer, timer->expires); |
| } |
| EXPORT_SYMBOL(add_timer); |
| |
| /** |
| * add_timer_on - start a timer on a particular CPU |
| * @timer: the timer to be added |
| * @cpu: the CPU to start it on |
| * |
| * This is not very scalable on SMP. Double adds are not possible. |
| */ |
| void add_timer_on(struct timer_list *timer, int cpu) |
| { |
| struct tvec_base *base = per_cpu(tvec_bases, cpu); |
| unsigned long flags; |
| |
| timer_stats_timer_set_start_info(timer); |
| BUG_ON(timer_pending(timer) || !timer->function); |
| spin_lock_irqsave(&base->lock, flags); |
| timer_set_base(timer, base); |
| debug_activate(timer, timer->expires); |
| internal_add_timer(base, timer); |
| spin_unlock_irqrestore(&base->lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(add_timer_on); |
| |
| /** |
| * del_timer - deactive a timer. |
| * @timer: the timer to be deactivated |
| * |
| * del_timer() deactivates a timer - this works on both active and inactive |
| * timers. |
| * |
| * The function returns whether it has deactivated a pending timer or not. |
| * (ie. del_timer() of an inactive timer returns 0, del_timer() of an |
| * active timer returns 1.) |
| */ |
| int del_timer(struct timer_list *timer) |
| { |
| struct tvec_base *base; |
| unsigned long flags; |
| int ret = 0; |
| |
| debug_assert_init(timer); |
| |
| timer_stats_timer_clear_start_info(timer); |
| if (timer_pending(timer)) { |
| base = lock_timer_base(timer, &flags); |
| ret = detach_if_pending(timer, base, true); |
| spin_unlock_irqrestore(&base->lock, flags); |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(del_timer); |
| |
| /** |
| * try_to_del_timer_sync - Try to deactivate a timer |
| * @timer: timer do del |
| * |
| * This function tries to deactivate a timer. Upon successful (ret >= 0) |
| * exit the timer is not queued and the handler is not running on any CPU. |
| */ |
| int try_to_del_timer_sync(struct timer_list *timer) |
| { |
| struct tvec_base *base; |
| unsigned long flags; |
| int ret = -1; |
| |
| debug_assert_init(timer); |
| |
| base = lock_timer_base(timer, &flags); |
| |
| if (base->running_timer != timer) { |
| timer_stats_timer_clear_start_info(timer); |
| ret = detach_if_pending(timer, base, true); |
| } |
| spin_unlock_irqrestore(&base->lock, flags); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(try_to_del_timer_sync); |
| |
| #ifdef CONFIG_SMP |
| /** |
| * del_timer_sync - deactivate a timer and wait for the handler to finish. |
| * @timer: the timer to be deactivated |
| * |
| * This function only differs from del_timer() on SMP: besides deactivating |
| * the timer it also makes sure the handler has finished executing on other |
| * CPUs. |
| * |
| * Synchronization rules: Callers must prevent restarting of the timer, |
| * otherwise this function is meaningless. It must not be called from |
| * interrupt contexts unless the timer is an irqsafe one. The caller must |
| * not hold locks which would prevent completion of the timer's |
| * handler. The timer's handler must not call add_timer_on(). Upon exit the |
| * timer is not queued and the handler is not running on any CPU. |
| * |
| * Note: For !irqsafe timers, you must not hold locks that are held in |
| * interrupt context while calling this function. Even if the lock has |
| * nothing to do with the timer in question. Here's why: |
| * |
| * CPU0 CPU1 |
| * ---- ---- |
| * <SOFTIRQ> |
| * call_timer_fn(); |
| * base->running_timer = mytimer; |
| * spin_lock_irq(somelock); |
| * <IRQ> |
| * spin_lock(somelock); |
| * del_timer_sync(mytimer); |
| * while (base->running_timer == mytimer); |
| * |
| * Now del_timer_sync() will never return and never release somelock. |
| * The interrupt on the other CPU is waiting to grab somelock but |
| * it has interrupted the softirq that CPU0 is waiting to finish. |
| * |
| * The function returns whether it has deactivated a pending timer or not. |
| */ |
| int del_timer_sync(struct timer_list *timer) |
| { |
| #ifdef CONFIG_LOCKDEP |
| unsigned long flags; |
| |
| /* |
| * If lockdep gives a backtrace here, please reference |
| * the synchronization rules above. |
| */ |
| local_irq_save(flags); |
| lock_map_acquire(&timer->lockdep_map); |
| lock_map_release(&timer->lockdep_map); |
| local_irq_restore(flags); |
| #endif |
| /* |
| * don't use it in hardirq context, because it |
| * could lead to deadlock. |
| */ |
| WARN_ON(in_irq() && !tbase_get_irqsafe(timer->base)); |
| for (;;) { |
| int ret = try_to_del_timer_sync(timer); |
| if (ret >= 0) |
| return ret; |
| cpu_relax(); |
| } |
| } |
| EXPORT_SYMBOL(del_timer_sync); |
| #endif |
| |
| static int cascade(struct tvec_base *base, struct tvec *tv, int index) |
| { |
| /* cascade all the timers from tv up one level */ |
| struct timer_list *timer, *tmp; |
| struct list_head tv_list; |
| |
| list_replace_init(tv->vec + index, &tv_list); |
| |
| /* |
| * We are removing _all_ timers from the list, so we |
| * don't have to detach them individually. |
| */ |
| list_for_each_entry_safe(timer, tmp, &tv_list, entry) { |
| BUG_ON(tbase_get_base(timer->base) != base); |
| /* No accounting, while moving them */ |
| __internal_add_timer(base, timer); |
| } |
| |
| return index; |
| } |
| |
| static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long), |
| unsigned long data) |
| { |
| int count = preempt_count(); |
| |
| #ifdef CONFIG_LOCKDEP |
| /* |
| * It is permissible to free the timer from inside the |
| * function that is called from it, this we need to take into |
| * account for lockdep too. To avoid bogus "held lock freed" |
| * warnings as well as problems when looking into |
| * timer->lockdep_map, make a copy and use that here. |
| */ |
| struct lockdep_map lockdep_map; |
| |
| lockdep_copy_map(&lockdep_map, &timer->lockdep_map); |
| #endif |
| /* |
| * Couple the lock chain with the lock chain at |
| * del_timer_sync() by acquiring the lock_map around the fn() |
| * call here and in del_timer_sync(). |
| */ |
| lock_map_acquire(&lockdep_map); |
| |
| trace_timer_expire_entry(timer); |
| fn(data); |
| trace_timer_expire_exit(timer); |
| |
| lock_map_release(&lockdep_map); |
| |
| if (count != preempt_count()) { |
| WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n", |
| fn, count, preempt_count()); |
| /* |
| * Restore the preempt count. That gives us a decent |
| * chance to survive and extract information. If the |
| * callback kept a lock held, bad luck, but not worse |
| * than the BUG() we had. |
| */ |
| preempt_count_set(count); |
| } |
| } |
| |
| #define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK) |
| |
| /** |
| * __run_timers - run all expired timers (if any) on this CPU. |
| * @base: the timer vector to be processed. |
| * |
| * This function cascades all vectors and executes all expired timer |
| * vectors. |
| */ |
| static inline void __run_timers(struct tvec_base *base) |
| { |
| struct timer_list *timer; |
| |
| spin_lock_irq(&base->lock); |
| if (catchup_timer_jiffies(base)) { |
| spin_unlock_irq(&base->lock); |
| return; |
| } |
| while (time_after_eq(jiffies, base->timer_jiffies)) { |
| struct list_head work_list; |
| struct list_head *head = &work_list; |
| int index = base->timer_jiffies & TVR_MASK; |
| |
| /* |
| * Cascade timers: |
| */ |
| if (!index && |
| (!cascade(base, &base->tv2, INDEX(0))) && |
| (!cascade(base, &base->tv3, INDEX(1))) && |
| !cascade(base, &base->tv4, INDEX(2))) |
| cascade(base, &base->tv5, INDEX(3)); |
| ++base->timer_jiffies; |
| list_replace_init(base->tv1.vec + index, head); |
| while (!list_empty(head)) { |
| void (*fn)(unsigned long); |
| unsigned long data; |
| bool irqsafe; |
| |
| timer = list_first_entry(head, struct timer_list,entry); |
| fn = timer->function; |
| data = timer->data; |
| irqsafe = tbase_get_irqsafe(timer->base); |
| |
| timer_stats_account_timer(timer); |
| |
| base->running_timer = timer; |
| detach_expired_timer(timer, base); |
| |
| if (irqsafe) { |
| spin_unlock(&base->lock); |
| call_timer_fn(timer, fn, data); |
| spin_lock(&base->lock); |
| } else { |
| spin_unlock_irq(&base->lock); |
| call_timer_fn(timer, fn, data); |
| spin_lock_irq(&base->lock); |
| } |
| } |
| } |
| base->running_timer = NULL; |
| spin_unlock_irq(&base->lock); |
| } |
| |
| #ifdef CONFIG_NO_HZ_COMMON |
| /* |
| * Find out when the next timer event is due to happen. This |
| * is used on S/390 to stop all activity when a CPU is idle. |
| * This function needs to be called with interrupts disabled. |
| */ |
| static unsigned long __next_timer_interrupt(struct tvec_base *base) |
| { |
| unsigned long timer_jiffies = base->timer_jiffies; |
| unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA; |
| int index, slot, array, found = 0; |
| struct timer_list *nte; |
| struct tvec *varray[4]; |
| |
| /* Look for timer events in tv1. */ |
| index = slot = timer_jiffies & TVR_MASK; |
| do { |
| list_for_each_entry(nte, base->tv1.vec + slot, entry) { |
| if (tbase_get_deferrable(nte->base)) |
| continue; |
| |
| found = 1; |
| expires = nte->expires; |
| /* Look at the cascade bucket(s)? */ |
| if (!index || slot < index) |
| goto cascade; |
| return expires; |
| } |
| slot = (slot + 1) & TVR_MASK; |
| } while (slot != index); |
| |
| cascade: |
| /* Calculate the next cascade event */ |
| if (index) |
| timer_jiffies += TVR_SIZE - index; |
| timer_jiffies >>= TVR_BITS; |
| |
| /* Check tv2-tv5. */ |
| varray[0] = &base->tv2; |
| varray[1] = &base->tv3; |
| varray[2] = &base->tv4; |
| varray[3] = &base->tv5; |
| |
| for (array = 0; array < 4; array++) { |
| struct tvec *varp = varray[array]; |
| |
| index = slot = timer_jiffies & TVN_MASK; |
| do { |
| list_for_each_entry(nte, varp->vec + slot, entry) { |
| if (tbase_get_deferrable(nte->base)) |
| continue; |
| |
| found = 1; |
| if (time_before(nte->expires, expires)) |
| expires = nte->expires; |
| } |
| /* |
| * Do we still search for the first timer or are |
| * we looking up the cascade buckets ? |
| */ |
| if (found) { |
| /* Look at the cascade bucket(s)? */ |
| if (!index || slot < index) |
| break; |
| return expires; |
| } |
| slot = (slot + 1) & TVN_MASK; |
| } while (slot != index); |
| |
| if (index) |
| timer_jiffies += TVN_SIZE - index; |
| timer_jiffies >>= TVN_BITS; |
| } |
| return expires; |
| } |
| |
| /* |
| * Check, if the next hrtimer event is before the next timer wheel |
| * event: |
| */ |
| static unsigned long cmp_next_hrtimer_event(unsigned long now, |
| unsigned long expires) |
| { |
| ktime_t hr_delta = hrtimer_get_next_event(); |
| struct timespec tsdelta; |
| unsigned long delta; |
| |
| if (hr_delta.tv64 == KTIME_MAX) |
| return expires; |
| |
| /* |
| * Expired timer available, let it expire in the next tick |
| */ |
| if (hr_delta.tv64 <= 0) |
| return now + 1; |
| |
| tsdelta = ktime_to_timespec(hr_delta); |
| delta = timespec_to_jiffies(&tsdelta); |
| |
| /* |
| * Limit the delta to the max value, which is checked in |
| * tick_nohz_stop_sched_tick(): |
| */ |
| if (delta > NEXT_TIMER_MAX_DELTA) |
| delta = NEXT_TIMER_MAX_DELTA; |
| |
| /* |
| * Take rounding errors in to account and make sure, that it |
| * expires in the next tick. Otherwise we go into an endless |
| * ping pong due to tick_nohz_stop_sched_tick() retriggering |
| * the timer softirq |
| */ |
| if (delta < 1) |
| delta = 1; |
| now += delta; |
| if (time_before(now, expires)) |
| return now; |
| return expires; |
| } |
| |
| /** |
| * get_next_timer_interrupt - return the jiffy of the next pending timer |
| * @now: current time (in jiffies) |
| */ |
| unsigned long get_next_timer_interrupt(unsigned long now) |
| { |
| struct tvec_base *base = __this_cpu_read(tvec_bases); |
| unsigned long expires = now + NEXT_TIMER_MAX_DELTA; |
| |
| /* |
| * Pretend that there is no timer pending if the cpu is offline. |
| * Possible pending timers will be migrated later to an active cpu. |
| */ |
| if (cpu_is_offline(smp_processor_id())) |
| return expires; |
| |
| spin_lock(&base->lock); |
| if (base->active_timers) { |
| if (time_before_eq(base->next_timer, base->timer_jiffies)) |
| base->next_timer = __next_timer_interrupt(base); |
| expires = base->next_timer; |
| } |
| spin_unlock(&base->lock); |
| |
| if (time_before_eq(expires, now)) |
| return now; |
| |
| return cmp_next_hrtimer_event(now, expires); |
| } |
| #endif |
| |
| /* |
| * Called from the timer interrupt handler to charge one tick to the current |
| * process. user_tick is 1 if the tick is user time, 0 for system. |
| */ |
| void update_process_times(int user_tick) |
| { |
| struct task_struct *p = current; |
| int cpu = smp_processor_id(); |
| |
| /* Note: this timer irq context must be accounted for as well. */ |
| account_process_tick(p, user_tick); |
| run_local_timers(); |
| rcu_check_callbacks(cpu, user_tick); |
| #ifdef CONFIG_IRQ_WORK |
| if (in_irq()) |
| irq_work_run(); |
| #endif |
| scheduler_tick(); |
| run_posix_cpu_timers(p); |
| } |
| |
| /* |
| * This function runs timers and the timer-tq in bottom half context. |
| */ |
| static void run_timer_softirq(struct softirq_action *h) |
| { |
| struct tvec_base *base = __this_cpu_read(tvec_bases); |
| |
| hrtimer_run_pending(); |
| |
| if (time_after_eq(jiffies, base->timer_jiffies)) |
| __run_timers(base); |
| } |
| |
| /* |
| * Called by the local, per-CPU timer interrupt on SMP. |
| */ |
| void run_local_timers(void) |
| { |
| hrtimer_run_queues(); |
| raise_softirq(TIMER_SOFTIRQ); |
| } |
| |
| #ifdef __ARCH_WANT_SYS_ALARM |
| |
| /* |
| * For backwards compatibility? This can be done in libc so Alpha |
| * and all newer ports shouldn't need it. |
| */ |
| SYSCALL_DEFINE1(alarm, unsigned int, seconds) |
| { |
| return alarm_setitimer(seconds); |
| } |
| |
| #endif |
| |
| static void process_timeout(unsigned long __data) |
| { |
| wake_up_process((struct task_struct *)__data); |
| } |
| |
| /** |
| * schedule_timeout - sleep until timeout |
| * @timeout: timeout value in jiffies |
| * |
| * Make the current task sleep until @timeout jiffies have |
| * 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 jiffies are guaranteed to |
| * pass before the routine returns. The routine will return 0 |
| * |
| * %TASK_INTERRUPTIBLE - the routine may return early if a signal is |
| * delivered to the current task. In this case the remaining time |
| * in jiffies will be returned, or 0 if the timer expired in time |
| * |
| * The current task state is guaranteed to be TASK_RUNNING when this |
| * routine returns. |
| * |
| * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule |
| * the CPU away without a bound on the timeout. In this case the return |
| * value will be %MAX_SCHEDULE_TIMEOUT. |
| * |
| * In all cases the return value is guaranteed to be non-negative. |
| */ |
| signed long __sched schedule_timeout(signed long timeout) |
| { |
| struct timer_list timer; |
| unsigned long expire; |
| |
| switch (timeout) |
| { |
| case MAX_SCHEDULE_TIMEOUT: |
| /* |
| * These two special cases are useful to be comfortable |
| * in the caller. Nothing more. We could take |
| * MAX_SCHEDULE_TIMEOUT from one of the negative value |
| * but I' d like to return a valid offset (>=0) to allow |
| * the caller to do everything it want with the retval. |
| */ |
| schedule(); |
| goto out; |
| default: |
| /* |
| * Another bit of PARANOID. Note that the retval will be |
| * 0 since no piece of kernel is supposed to do a check |
| * for a negative retval of schedule_timeout() (since it |
| * should never happens anyway). You just have the printk() |
| * that will tell you if something is gone wrong and where. |
| */ |
| if (timeout < 0) { |
| printk(KERN_ERR "schedule_timeout: wrong timeout " |
| "value %lx\n", timeout); |
| dump_stack(); |
| current->state = TASK_RUNNING; |
| goto out; |
| } |
| } |
| |
| expire = timeout + jiffies; |
| |
| setup_timer_on_stack(&timer, process_timeout, (unsigned long)current); |
| __mod_timer(&timer, expire, false, TIMER_NOT_PINNED); |
| schedule(); |
| del_singleshot_timer_sync(&timer); |
| |
| /* Remove the timer from the object tracker */ |
| destroy_timer_on_stack(&timer); |
| |
| timeout = expire - jiffies; |
| |
| out: |
| return timeout < 0 ? 0 : timeout; |
| } |
| EXPORT_SYMBOL(schedule_timeout); |
| |
| /* |
| * We can use __set_current_state() here because schedule_timeout() calls |
| * schedule() unconditionally. |
| */ |
| signed long __sched schedule_timeout_interruptible(signed long timeout) |
| { |
| __set_current_state(TASK_INTERRUPTIBLE); |
| return schedule_timeout(timeout); |
| } |
| EXPORT_SYMBOL(schedule_timeout_interruptible); |
| |
| signed long __sched schedule_timeout_killable(signed long timeout) |
| { |
| __set_current_state(TASK_KILLABLE); |
| return schedule_timeout(timeout); |
| } |
| EXPORT_SYMBOL(schedule_timeout_killable); |
| |
| signed long __sched schedule_timeout_uninterruptible(signed long timeout) |
| { |
| __set_current_state(TASK_UNINTERRUPTIBLE); |
| return schedule_timeout(timeout); |
| } |
| EXPORT_SYMBOL(schedule_timeout_uninterruptible); |
| |
| static int init_timers_cpu(int cpu) |
| { |
| int j; |
| struct tvec_base *base; |
| static char tvec_base_done[NR_CPUS]; |
| |
| if (!tvec_base_done[cpu]) { |
| static char boot_done; |
| |
| if (boot_done) { |
| /* |
| * The APs use this path later in boot |
| */ |
| base = kzalloc_node(sizeof(*base), GFP_KERNEL, |
| cpu_to_node(cpu)); |
| if (!base) |
| return -ENOMEM; |
| |
| /* Make sure tvec_base has TIMER_FLAG_MASK bits free */ |
| if (WARN_ON(base != tbase_get_base(base))) { |
| kfree(base); |
| return -ENOMEM; |
| } |
| per_cpu(tvec_bases, cpu) = base; |
| } else { |
| /* |
| * This is for the boot CPU - we use compile-time |
| * static initialisation because per-cpu memory isn't |
| * ready yet and because the memory allocators are not |
| * initialised either. |
| */ |
| boot_done = 1; |
| base = &boot_tvec_bases; |
| } |
| spin_lock_init(&base->lock); |
| tvec_base_done[cpu] = 1; |
| base->cpu = cpu; |
| } else { |
| base = per_cpu(tvec_bases, cpu); |
| } |
| |
| |
| for (j = 0; j < TVN_SIZE; j++) { |
| INIT_LIST_HEAD(base->tv5.vec + j); |
| INIT_LIST_HEAD(base->tv4.vec + j); |
| INIT_LIST_HEAD(base->tv3.vec + j); |
| INIT_LIST_HEAD(base->tv2.vec + j); |
| } |
| for (j = 0; j < TVR_SIZE; j++) |
| INIT_LIST_HEAD(base->tv1.vec + j); |
| |
| base->timer_jiffies = jiffies; |
| base->next_timer = base->timer_jiffies; |
| base->active_timers = 0; |
| base->all_timers = 0; |
| return 0; |
| } |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head) |
| { |
| struct timer_list *timer; |
| |
| while (!list_empty(head)) { |
| timer = list_first_entry(head, struct timer_list, entry); |
| /* We ignore the accounting on the dying cpu */ |
| detach_timer(timer, false); |
| timer_set_base(timer, new_base); |
| internal_add_timer(new_base, timer); |
| } |
| } |
| |
| static void migrate_timers(int cpu) |
| { |
| struct tvec_base *old_base; |
| struct tvec_base *new_base; |
| int i; |
| |
| BUG_ON(cpu_online(cpu)); |
| old_base = per_cpu(tvec_bases, cpu); |
| new_base = get_cpu_var(tvec_bases); |
| /* |
| * The caller is globally serialized and nobody else |
| * takes two locks at once, deadlock is not possible. |
| */ |
| spin_lock_irq(&new_base->lock); |
| spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); |
| |
| BUG_ON(old_base->running_timer); |
| |
| for (i = 0; i < TVR_SIZE; i++) |
| migrate_timer_list(new_base, old_base->tv1.vec + i); |
| for (i = 0; i < TVN_SIZE; i++) { |
| migrate_timer_list(new_base, old_base->tv2.vec + i); |
| migrate_timer_list(new_base, old_base->tv3.vec + i); |
| migrate_timer_list(new_base, old_base->tv4.vec + i); |
| migrate_timer_list(new_base, old_base->tv5.vec + i); |
| } |
| |
| spin_unlock(&old_base->lock); |
| spin_unlock_irq(&new_base->lock); |
| put_cpu_var(tvec_bases); |
| } |
| #endif /* CONFIG_HOTPLUG_CPU */ |
| |
| static int timer_cpu_notify(struct notifier_block *self, |
| unsigned long action, void *hcpu) |
| { |
| long cpu = (long)hcpu; |
| int err; |
| |
| switch(action) { |
| case CPU_UP_PREPARE: |
| case CPU_UP_PREPARE_FROZEN: |
| err = init_timers_cpu(cpu); |
| if (err < 0) |
| return notifier_from_errno(err); |
| break; |
| #ifdef CONFIG_HOTPLUG_CPU |
| case CPU_DEAD: |
| case CPU_DEAD_FROZEN: |
| migrate_timers(cpu); |
| break; |
| #endif |
| default: |
| break; |
| } |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block timers_nb = { |
| .notifier_call = timer_cpu_notify, |
| }; |
| |
| |
| void __init init_timers(void) |
| { |
| int err; |
| |
| /* ensure there are enough low bits for flags in timer->base pointer */ |
| BUILD_BUG_ON(__alignof__(struct tvec_base) & TIMER_FLAG_MASK); |
| |
| err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE, |
| (void *)(long)smp_processor_id()); |
| BUG_ON(err != NOTIFY_OK); |
| |
| init_timer_stats(); |
| register_cpu_notifier(&timers_nb); |
| open_softirq(TIMER_SOFTIRQ, run_timer_softirq); |
| } |
| |
| /** |
| * msleep - sleep safely even with waitqueue interruptions |
| * @msecs: Time in milliseconds to sleep for |
| */ |
| void msleep(unsigned int msecs) |
| { |
| unsigned long timeout = msecs_to_jiffies(msecs) + 1; |
| |
| while (timeout) |
| timeout = schedule_timeout_uninterruptible(timeout); |
| } |
| |
| EXPORT_SYMBOL(msleep); |
| |
| /** |
| * msleep_interruptible - sleep waiting for signals |
| * @msecs: Time in milliseconds to sleep for |
| */ |
| unsigned long msleep_interruptible(unsigned int msecs) |
| { |
| unsigned long timeout = msecs_to_jiffies(msecs) + 1; |
| |
| while (timeout && !signal_pending(current)) |
| timeout = schedule_timeout_interruptible(timeout); |
| return jiffies_to_msecs(timeout); |
| } |
| |
| EXPORT_SYMBOL(msleep_interruptible); |
| |
| static int __sched do_usleep_range(unsigned long min, unsigned long max) |
| { |
| ktime_t kmin; |
| unsigned long delta; |
| |
| kmin = ktime_set(0, min * NSEC_PER_USEC); |
| delta = (max - min) * NSEC_PER_USEC; |
| return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL); |
| } |
| |
| /** |
| * usleep_range - Drop in replacement for udelay where wakeup is flexible |
| * @min: Minimum time in usecs to sleep |
| * @max: Maximum time in usecs to sleep |
| */ |
| void usleep_range(unsigned long min, unsigned long max) |
| { |
| __set_current_state(TASK_UNINTERRUPTIBLE); |
| do_usleep_range(min, max); |
| } |
| EXPORT_SYMBOL(usleep_range); |