diff options
| -rw-r--r-- | include/linux/hrtimer.h | 119 | ||||
| -rw-r--r-- | include/linux/hrtimer_defs.h | 104 | ||||
| -rw-r--r-- | include/linux/jiffies.h | 15 | ||||
| -rw-r--r-- | kernel/time/clockevents.c | 2 | ||||
| -rw-r--r-- | kernel/time/clocksource.c | 2 | ||||
| -rw-r--r-- | kernel/time/hrtimer.c | 18 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 10 | ||||
| -rw-r--r-- | kernel/time/timekeeping.c | 24 | ||||
| -rw-r--r-- | kernel/time/timer.c | 45 |
9 files changed, 195 insertions, 144 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 641c4567cfa7..aa1e65ccb615 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -18,12 +18,8 @@ #include <linux/list.h> #include <linux/percpu-defs.h> #include <linux/rbtree.h> -#include <linux/seqlock.h> #include <linux/timer.h> -struct hrtimer_clock_base; -struct hrtimer_cpu_base; - /* * Mode arguments of xxx_hrtimer functions: * @@ -98,107 +94,6 @@ struct hrtimer_sleeper { struct task_struct *task; }; -#ifdef CONFIG_64BIT -# define __hrtimer_clock_base_align ____cacheline_aligned -#else -# define __hrtimer_clock_base_align -#endif - -/** - * struct hrtimer_clock_base - the timer base for a specific clock - * @cpu_base: per cpu clock base - * @index: clock type index for per_cpu support when moving a - * timer to a base on another cpu. - * @clockid: clock id for per_cpu support - * @seq: seqcount around __run_hrtimer - * @running: pointer to the currently running hrtimer - * @active: red black tree root node for the active timers - * @get_time: function to retrieve the current time of the clock - * @offset: offset of this clock to the monotonic base - */ -struct hrtimer_clock_base { - struct hrtimer_cpu_base *cpu_base; - unsigned int index; - clockid_t clockid; - seqcount_raw_spinlock_t seq; - struct hrtimer *running; - struct timerqueue_head active; - ktime_t (*get_time)(void); - ktime_t offset; -} __hrtimer_clock_base_align; - -enum hrtimer_base_type { - HRTIMER_BASE_MONOTONIC, - HRTIMER_BASE_REALTIME, - HRTIMER_BASE_BOOTTIME, - HRTIMER_BASE_TAI, - HRTIMER_BASE_MONOTONIC_SOFT, - HRTIMER_BASE_REALTIME_SOFT, - HRTIMER_BASE_BOOTTIME_SOFT, - HRTIMER_BASE_TAI_SOFT, - HRTIMER_MAX_CLOCK_BASES, -}; - -/** - * struct hrtimer_cpu_base - the per cpu clock bases - * @lock: lock protecting the base and associated clock bases - * and timers - * @cpu: cpu number - * @active_bases: Bitfield to mark bases with active timers - * @clock_was_set_seq: Sequence counter of clock was set events - * @hres_active: State of high resolution mode - * @in_hrtirq: hrtimer_interrupt() is currently executing - * @hang_detected: The last hrtimer interrupt detected a hang - * @softirq_activated: displays, if the softirq is raised - update of softirq - * related settings is not required then. - * @nr_events: Total number of hrtimer interrupt events - * @nr_retries: Total number of hrtimer interrupt retries - * @nr_hangs: Total number of hrtimer interrupt hangs - * @max_hang_time: Maximum time spent in hrtimer_interrupt - * @softirq_expiry_lock: Lock which is taken while softirq based hrtimer are - * expired - * @online: CPU is online from an hrtimers point of view - * @timer_waiters: A hrtimer_cancel() invocation waits for the timer - * callback to finish. - * @expires_next: absolute time of the next event, is required for remote - * hrtimer enqueue; it is the total first expiry time (hard - * and soft hrtimer are taken into account) - * @next_timer: Pointer to the first expiring timer - * @softirq_expires_next: Time to check, if soft queues needs also to be expired - * @softirq_next_timer: Pointer to the first expiring softirq based timer - * @clock_base: array of clock bases for this cpu - * - * Note: next_timer is just an optimization for __remove_hrtimer(). - * Do not dereference the pointer because it is not reliable on - * cross cpu removals. - */ -struct hrtimer_cpu_base { - raw_spinlock_t lock; - unsigned int cpu; - unsigned int active_bases; - unsigned int clock_was_set_seq; - unsigned int hres_active : 1, - in_hrtirq : 1, - hang_detected : 1, - softirq_activated : 1, - online : 1; -#ifdef CONFIG_HIGH_RES_TIMERS - unsigned int nr_events; - unsigned short nr_retries; - unsigned short nr_hangs; - unsigned int max_hang_time; -#endif -#ifdef CONFIG_PREEMPT_RT - spinlock_t softirq_expiry_lock; - atomic_t timer_waiters; -#endif - ktime_t expires_next; - struct hrtimer *next_timer; - ktime_t softirq_expires_next; - struct hrtimer *softirq_next_timer; - struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; -} ____cacheline_aligned; - static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) { timer->node.expires = time; @@ -447,20 +342,12 @@ extern u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); /** - * hrtimer_forward_now - forward the timer expiry so it expires after now + * hrtimer_forward_now() - forward the timer expiry so it expires after now * @timer: hrtimer to forward * @interval: the interval to forward * - * Forward the timer expiry so it will expire after the current time - * of the hrtimer clock base. Returns the number of overruns. - * - * Can be safely called from the callback function of @timer. If - * called from other contexts @timer must neither be enqueued nor - * running the callback and the caller needs to take care of - * serialization. - * - * Note: This only updates the timer expiry value and does not requeue - * the timer. + * It is a variant of hrtimer_forward(). The timer will expire after the current + * time of the hrtimer clock base. See hrtimer_forward() for details. */ static inline u64 hrtimer_forward_now(struct hrtimer *timer, ktime_t interval) diff --git a/include/linux/hrtimer_defs.h b/include/linux/hrtimer_defs.h index 2d3e3c5fb946..c3b4b7ed7c16 100644 --- a/include/linux/hrtimer_defs.h +++ b/include/linux/hrtimer_defs.h @@ -3,6 +3,8 @@ #define _LINUX_HRTIMER_DEFS_H #include <linux/ktime.h> +#include <linux/timerqueue.h> +#include <linux/seqlock.h> #ifdef CONFIG_HIGH_RES_TIMERS @@ -24,4 +26,106 @@ #endif +#ifdef CONFIG_64BIT +# define __hrtimer_clock_base_align ____cacheline_aligned +#else +# define __hrtimer_clock_base_align +#endif + +/** + * struct hrtimer_clock_base - the timer base for a specific clock + * @cpu_base: per cpu clock base + * @index: clock type index for per_cpu support when moving a + * timer to a base on another cpu. + * @clockid: clock id for per_cpu support + * @seq: seqcount around __run_hrtimer + * @running: pointer to the currently running hrtimer + * @active: red black tree root node for the active timers + * @get_time: function to retrieve the current time of the clock + * @offset: offset of this clock to the monotonic base + */ +struct hrtimer_clock_base { + struct hrtimer_cpu_base *cpu_base; + unsigned int index; + clockid_t clockid; + seqcount_raw_spinlock_t seq; + struct hrtimer *running; + struct timerqueue_head active; + ktime_t (*get_time)(void); + ktime_t offset; +} __hrtimer_clock_base_align; + +enum hrtimer_base_type { + HRTIMER_BASE_MONOTONIC, + HRTIMER_BASE_REALTIME, + HRTIMER_BASE_BOOTTIME, + HRTIMER_BASE_TAI, + HRTIMER_BASE_MONOTONIC_SOFT, + HRTIMER_BASE_REALTIME_SOFT, + HRTIMER_BASE_BOOTTIME_SOFT, + HRTIMER_BASE_TAI_SOFT, + HRTIMER_MAX_CLOCK_BASES, +}; + +/** + * struct hrtimer_cpu_base - the per cpu clock bases + * @lock: lock protecting the base and associated clock bases + * and timers + * @cpu: cpu number + * @active_bases: Bitfield to mark bases with active timers + * @clock_was_set_seq: Sequence counter of clock was set events + * @hres_active: State of high resolution mode + * @in_hrtirq: hrtimer_interrupt() is currently executing + * @hang_detected: The last hrtimer interrupt detected a hang + * @softirq_activated: displays, if the softirq is raised - update of softirq + * related settings is not required then. + * @nr_events: Total number of hrtimer interrupt events + * @nr_retries: Total number of hrtimer interrupt retries + * @nr_hangs: Total number of hrtimer interrupt hangs + * @max_hang_time: Maximum time spent in hrtimer_interrupt + * @softirq_expiry_lock: Lock which is taken while softirq based hrtimer are + * expired + * @online: CPU is online from an hrtimers point of view + * @timer_waiters: A hrtimer_cancel() invocation waits for the timer + * callback to finish. + * @expires_next: absolute time of the next event, is required for remote + * hrtimer enqueue; it is the total first expiry time (hard + * and soft hrtimer are taken into account) + * @next_timer: Pointer to the first expiring timer + * @softirq_expires_next: Time to check, if soft queues needs also to be expired + * @softirq_next_timer: Pointer to the first expiring softirq based timer + * @clock_base: array of clock bases for this cpu + * + * Note: next_timer is just an optimization for __remove_hrtimer(). + * Do not dereference the pointer because it is not reliable on + * cross cpu removals. + */ +struct hrtimer_cpu_base { + raw_spinlock_t lock; + unsigned int cpu; + unsigned int active_bases; + unsigned int clock_was_set_seq; + unsigned int hres_active : 1, + in_hrtirq : 1, + hang_detected : 1, + softirq_activated : 1, + online : 1; +#ifdef CONFIG_HIGH_RES_TIMERS + unsigned int nr_events; + unsigned short nr_retries; + unsigned short nr_hangs; + unsigned int max_hang_time; +#endif +#ifdef CONFIG_PREEMPT_RT + spinlock_t softirq_expiry_lock; + atomic_t timer_waiters; +#endif + ktime_t expires_next; + struct hrtimer *next_timer; + ktime_t softirq_expires_next; + struct hrtimer *softirq_next_timer; + struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; +} ____cacheline_aligned; + + #endif diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h index e0ae2a43e0eb..d9f1435a5a13 100644 --- a/include/linux/jiffies.h +++ b/include/linux/jiffies.h @@ -102,12 +102,15 @@ static inline u64 get_jiffies_64(void) } #endif -/* - * These inlines deal with timer wrapping correctly. You are - * strongly encouraged to use them: - * 1. Because people otherwise forget - * 2. Because if the timer wrap changes in future you won't have to - * alter your driver code. +/** + * DOC: General information about time_* inlines + * + * These inlines deal with timer wrapping correctly. You are strongly encouraged + * to use them: + * + * #. Because people otherwise forget + * #. Because if the timer wrap changes in future you won't have to alter your + * driver code. */ /** diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 960143b183cd..a7ca458cdd9c 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -659,7 +659,7 @@ void tick_cleanup_dead_cpu(int cpu) #endif #ifdef CONFIG_SYSFS -static struct bus_type clockevents_subsys = { +static const struct bus_type clockevents_subsys = { .name = "clockevents", .dev_name = "clockevent", }; diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 3052b1f1168e..4ef06651ad07 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -1468,7 +1468,7 @@ static struct attribute *clocksource_attrs[] = { }; ATTRIBUTE_GROUPS(clocksource); -static struct bus_type clocksource_subsys = { +static const struct bus_type clocksource_subsys = { .name = "clocksource", .dev_name = "clocksource", }; diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index edb0f821dcea..5a98b35b0576 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1021,21 +1021,23 @@ void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) } /** - * hrtimer_forward - forward the timer expiry + * hrtimer_forward() - forward the timer expiry * @timer: hrtimer to forward * @now: forward past this time * @interval: the interval to forward * * Forward the timer expiry so it will expire in the future. - * Returns the number of overruns. * - * Can be safely called from the callback function of @timer. If - * called from other contexts @timer must neither be enqueued nor - * running the callback and the caller needs to take care of - * serialization. + * .. note:: + * This only updates the timer expiry value and does not requeue the timer. * - * Note: This only updates the timer expiry value and does not requeue - * the timer. + * There is also a variant of the function hrtimer_forward_now(). + * + * Context: Can be safely called from the callback function of @timer. If called + * from other contexts @timer must neither be enqueued nor running the + * callback and the caller needs to take care of serialization. + * + * Return: The number of overruns are returned. */ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval) { diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 01fb50c1b17e..7c9efe3d9d56 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -799,6 +799,16 @@ static inline bool local_timer_softirq_pending(void) return local_softirq_pending() & BIT(TIMER_SOFTIRQ); } +/** + * tick_nohz_next_event() - return the clock monotonic based next event + * @ts: pointer to tick_sched struct + * @cpu: CPU number + * + * Return: + * *%0 - When the next event is a maximum of TICK_NSEC in the future + * and the tick is not stopped yet + * *%next_event - Next event based on clock monotonic + */ static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu) { u64 basemono, next_tick, delta, expires; diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 266d02809dbb..8aab7ed41490 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1180,13 +1180,15 @@ static int adjust_historical_crosststamp(struct system_time_snapshot *history, } /* - * cycle_between - true if test occurs chronologically between before and after + * timestamp_in_interval - true if ts is chronologically in [start, end] + * + * True if ts occurs chronologically at or after start, and before or at end. */ -static bool cycle_between(u64 before, u64 test, u64 after) +static bool timestamp_in_interval(u64 start, u64 end, u64 ts) { - if (test > before && test < after) + if (ts >= start && ts <= end) return true; - if (test < before && before > after) + if (start > end && (ts >= start || ts <= end)) return true; return false; } @@ -1246,7 +1248,7 @@ int get_device_system_crosststamp(int (*get_time_fn) */ now = tk_clock_read(&tk->tkr_mono); interval_start = tk->tkr_mono.cycle_last; - if (!cycle_between(interval_start, cycles, now)) { + if (!timestamp_in_interval(interval_start, now, cycles)) { clock_was_set_seq = tk->clock_was_set_seq; cs_was_changed_seq = tk->cs_was_changed_seq; cycles = interval_start; @@ -1259,10 +1261,8 @@ int get_device_system_crosststamp(int (*get_time_fn) tk_core.timekeeper.offs_real); base_raw = tk->tkr_raw.base; - nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, - system_counterval.cycles); - nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, - system_counterval.cycles); + nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, cycles); + nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, cycles); } while (read_seqcount_retry(&tk_core.seq, seq)); xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real); @@ -1277,13 +1277,13 @@ int get_device_system_crosststamp(int (*get_time_fn) bool discontinuity; /* - * Check that the counter value occurs after the provided + * Check that the counter value is not before the provided * history reference and that the history doesn't cross a * clocksource change */ if (!history_begin || - !cycle_between(history_begin->cycles, - system_counterval.cycles, cycles) || + !timestamp_in_interval(history_begin->cycles, + cycles, system_counterval.cycles) || history_begin->cs_was_changed_seq != cs_was_changed_seq) return -EINVAL; partial_history_cycles = cycles - system_counterval.cycles; diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 352b161113cd..d44dba1d4af0 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -196,6 +196,51 @@ EXPORT_SYMBOL(jiffies_64); # define BASE_DEF 0 #endif +/** + * struct timer_base - Per CPU timer base (number of base depends on config) + * @lock: Lock protecting the timer_base + * @running_timer: When expiring timers, the lock is dropped. To make + * sure not to race agains deleting/modifying a + * currently running timer, the pointer is set to the + * timer, which expires at the moment. If no timer is + * running, the pointer is NULL. + * @expiry_lock: PREEMPT_RT only: Lock is taken in softirq around + * timer expiry callback execution and when trying to + * delete a running timer and it wasn't successful in + * the first glance. It prevents priority inversion + * when callback was preempted on a remote CPU and a + * caller tries to delete the running timer. It also + * prevents a life lock, when the task which tries to + * delete a timer preempted the softirq thread which + * is running the timer callback function. + * @timer_waiters: PREEMPT_RT only: Tells, if there is a waiter + * waiting for the end of the timer callback function + * execution. + * @clk: clock of the timer base; is updated before enqueue + * of a timer; during expiry, it is 1 offset ahead of + * jiffies to avoid endless requeuing to current + * jiffies + * @next_expiry: expiry value of the first timer; it is updated when + * finding the next timer and during enqueue; the + * value is not valid, when next_expiry_recalc is set + * @cpu: Number of CPU the timer base belongs to + * @next_expiry_recalc: States, whether a recalculation of next_expiry is + * required. Value is set true, when a timer was + * deleted. + * @is_idle: Is set, when timer_base is idle. It is triggered by NOHZ + * code. This state is only used in standard + * base. Deferrable timers, which are enqueued remotely + * never wake up an idle CPU. So no matter of supporting it + * for this base. + * @timers_pending: Is set, when a timer is pending in the base. It is only + * reliable when next_expiry_recalc is not set. + * @pending_map: bitmap of the timer wheel; each bit reflects a + * bucket of the wheel. When a bit is set, at least a + * single timer is enqueued in the related bucket. + * @vectors: Array of lists; Each array member reflects a bucket + * of the timer wheel. The list contains all timers + * which are enqueued into a specific bucket. + */ struct timer_base { raw_spinlock_t lock; struct timer_list *running_timer; |