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-rw-r--r--include/linux/hrtimer.h260
1 files changed, 235 insertions, 25 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index fca93025ab5..37f9279192a 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -21,22 +21,72 @@
#include <linux/list.h>
#include <linux/wait.h>
+struct hrtimer_clock_base;
+struct hrtimer_cpu_base;
+
/*
* Mode arguments of xxx_hrtimer functions:
*/
enum hrtimer_mode {
- HRTIMER_ABS, /* Time value is absolute */
- HRTIMER_REL, /* Time value is relative to now */
+ HRTIMER_MODE_ABS, /* Time value is absolute */
+ HRTIMER_MODE_REL, /* Time value is relative to now */
};
+/*
+ * Return values for the callback function
+ */
enum hrtimer_restart {
- HRTIMER_NORESTART,
- HRTIMER_RESTART,
+ HRTIMER_NORESTART, /* Timer is not restarted */
+ HRTIMER_RESTART, /* Timer must be restarted */
};
-#define HRTIMER_INACTIVE ((void *)1UL)
+/*
+ * hrtimer callback modes:
+ *
+ * HRTIMER_CB_SOFTIRQ: Callback must run in softirq context
+ * HRTIMER_CB_IRQSAFE: Callback may run in hardirq context
+ * HRTIMER_CB_IRQSAFE_NO_RESTART: Callback may run in hardirq context and
+ * does not restart the timer
+ * HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: Callback must run in softirq context
+ * Special mode for tick emultation
+ */
+enum hrtimer_cb_mode {
+ HRTIMER_CB_SOFTIRQ,
+ HRTIMER_CB_IRQSAFE,
+ HRTIMER_CB_IRQSAFE_NO_RESTART,
+ HRTIMER_CB_IRQSAFE_NO_SOFTIRQ,
+};
-struct hrtimer_base;
+/*
+ * Values to track state of the timer
+ *
+ * Possible states:
+ *
+ * 0x00 inactive
+ * 0x01 enqueued into rbtree
+ * 0x02 callback function running
+ * 0x04 callback pending (high resolution mode)
+ *
+ * Special case:
+ * 0x03 callback function running and enqueued
+ * (was requeued on another CPU)
+ * The "callback function running and enqueued" status is only possible on
+ * SMP. It happens for example when a posix timer expired and the callback
+ * queued a signal. Between dropping the lock which protects the posix timer
+ * and reacquiring the base lock of the hrtimer, another CPU can deliver the
+ * signal and rearm the timer. We have to preserve the callback running state,
+ * as otherwise the timer could be removed before the softirq code finishes the
+ * the handling of the timer.
+ *
+ * The HRTIMER_STATE_ENQUEUE bit is always or'ed to the current state to
+ * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.
+ *
+ * All state transitions are protected by cpu_base->lock.
+ */
+#define HRTIMER_STATE_INACTIVE 0x00
+#define HRTIMER_STATE_ENQUEUED 0x01
+#define HRTIMER_STATE_CALLBACK 0x02
+#define HRTIMER_STATE_PENDING 0x04
/**
* struct hrtimer - the basic hrtimer structure
@@ -46,14 +96,34 @@ struct hrtimer_base;
* which the timer is based.
* @function: timer expiry callback function
* @base: pointer to the timer base (per cpu and per clock)
+ * @state: state information (See bit values above)
+ * @cb_mode: high resolution timer feature to select the callback execution
+ * mode
+ * @cb_entry: list head to enqueue an expired timer into the callback list
+ * @start_site: timer statistics field to store the site where the timer
+ * was started
+ * @start_comm: timer statistics field to store the name of the process which
+ * started the timer
+ * @start_pid: timer statistics field to store the pid of the task which
+ * started the timer
*
- * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
+ * The hrtimer structure must be initialized by hrtimer_init()
*/
struct hrtimer {
- struct rb_node node;
- ktime_t expires;
- int (*function)(struct hrtimer *);
- struct hrtimer_base *base;
+ struct rb_node node;
+ ktime_t expires;
+ enum hrtimer_restart (*function)(struct hrtimer *);
+ struct hrtimer_clock_base *base;
+ unsigned long state;
+#ifdef CONFIG_HIGH_RES_TIMERS
+ enum hrtimer_cb_mode cb_mode;
+ struct list_head cb_entry;
+#endif
+#ifdef CONFIG_TIMER_STATS
+ void *start_site;
+ char start_comm[16];
+ int start_pid;
+#endif
};
/**
@@ -70,37 +140,114 @@ struct hrtimer_sleeper {
/**
* struct hrtimer_base - the timer base for a specific clock
- * @index: clock type index for per_cpu support when moving a timer
- * to a base on another cpu.
- * @lock: lock protecting the base and associated timers
+ * @index: clock type index for per_cpu support when moving a
+ * timer to a base on another cpu.
* @active: red black tree root node for the active timers
* @first: pointer to the timer node which expires first
* @resolution: the resolution of the clock, in nanoseconds
* @get_time: function to retrieve the current time of the clock
* @get_softirq_time: function to retrieve the current time from the softirq
- * @curr_timer: the timer which is executing a callback right now
* @softirq_time: the time when running the hrtimer queue in the softirq
- * @lock_key: the lock_class_key for use with lockdep
+ * @cb_pending: list of timers where the callback is pending
+ * @offset: offset of this clock to the monotonic base
+ * @reprogram: function to reprogram the timer event
*/
-struct hrtimer_base {
+struct hrtimer_clock_base {
+ struct hrtimer_cpu_base *cpu_base;
clockid_t index;
- spinlock_t lock;
struct rb_root active;
struct rb_node *first;
ktime_t resolution;
ktime_t (*get_time)(void);
ktime_t (*get_softirq_time)(void);
- struct hrtimer *curr_timer;
ktime_t softirq_time;
- struct lock_class_key lock_key;
+#ifdef CONFIG_HIGH_RES_TIMERS
+ ktime_t offset;
+ int (*reprogram)(struct hrtimer *t,
+ struct hrtimer_clock_base *b,
+ ktime_t n);
+#endif
+};
+
+#define HRTIMER_MAX_CLOCK_BASES 2
+
+/*
+ * struct hrtimer_cpu_base - the per cpu clock bases
+ * @lock: lock protecting the base and associated clock bases
+ * and timers
+ * @lock_key: the lock_class_key for use with lockdep
+ * @clock_base: array of clock bases for this cpu
+ * @curr_timer: the timer which is executing a callback right now
+ * @expires_next: absolute time of the next event which was scheduled
+ * via clock_set_next_event()
+ * @hres_active: State of high resolution mode
+ * @check_clocks: Indictator, when set evaluate time source and clock
+ * event devices whether high resolution mode can be
+ * activated.
+ * @cb_pending: Expired timers are moved from the rbtree to this
+ * list in the timer interrupt. The list is processed
+ * in the softirq.
+ * @nr_events: Total number of timer interrupt events
+ */
+struct hrtimer_cpu_base {
+ spinlock_t lock;
+ struct lock_class_key lock_key;
+ struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
+#ifdef CONFIG_HIGH_RES_TIMERS
+ ktime_t expires_next;
+ int hres_active;
+ struct list_head cb_pending;
+ unsigned long nr_events;
+#endif
};
+#ifdef CONFIG_HIGH_RES_TIMERS
+struct clock_event_device;
+
+extern void clock_was_set(void);
+extern void hrtimer_interrupt(struct clock_event_device *dev);
+
+/*
+ * In high resolution mode the time reference must be read accurate
+ */
+static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
+{
+ return timer->base->get_time();
+}
+
+/*
+ * The resolution of the clocks. The resolution value is returned in
+ * the clock_getres() system call to give application programmers an
+ * idea of the (in)accuracy of timers. Timer values are rounded up to
+ * this resolution values.
+ */
+# define KTIME_HIGH_RES (ktime_t) { .tv64 = 1 }
+# define KTIME_MONOTONIC_RES KTIME_HIGH_RES
+
+#else
+
+# define KTIME_MONOTONIC_RES KTIME_LOW_RES
+
/*
* clock_was_set() is a NOP for non- high-resolution systems. The
* time-sorted order guarantees that a timer does not expire early and
* is expired in the next softirq when the clock was advanced.
*/
-#define clock_was_set() do { } while (0)
+static inline void clock_was_set(void) { }
+
+/*
+ * In non high resolution mode the time reference is taken from
+ * the base softirq time variable.
+ */
+static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
+{
+ return timer->base->softirq_time;
+}
+
+#endif
+
+extern ktime_t ktime_get(void);
+extern ktime_t ktime_get_real(void);
/* Exported timer functions: */
@@ -114,19 +261,33 @@ extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
extern int hrtimer_cancel(struct hrtimer *timer);
extern int hrtimer_try_to_cancel(struct hrtimer *timer);
-#define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS)
+static inline int hrtimer_restart(struct hrtimer *timer)
+{
+ return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS);
+}
/* Query timers: */
extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
-#ifdef CONFIG_NO_IDLE_HZ
extern ktime_t hrtimer_get_next_event(void);
-#endif
+/*
+ * A timer is active, when it is enqueued into the rbtree or the callback
+ * function is running.
+ */
static inline int hrtimer_active(const struct hrtimer *timer)
{
- return rb_parent(&timer->node) != &timer->node;
+ return timer->state != HRTIMER_STATE_INACTIVE;
+}
+
+/*
+ * Helper function to check, whether the timer is on one of the queues
+ */
+static inline int hrtimer_is_queued(struct hrtimer *timer)
+{
+ return timer->state &
+ (HRTIMER_STATE_ENQUEUED | HRTIMER_STATE_PENDING);
}
/* Forward a hrtimer so it expires after now: */
@@ -149,4 +310,53 @@ extern void hrtimer_run_queues(void);
/* Bootup initialization: */
extern void __init hrtimers_init(void);
+#if BITS_PER_LONG < 64
+extern unsigned long ktime_divns(const ktime_t kt, s64 div);
+#else /* BITS_PER_LONG < 64 */
+# define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div))
+#endif
+
+/* Show pending timers: */
+extern void sysrq_timer_list_show(void);
+
+/*
+ * Timer-statistics info:
+ */
+#ifdef CONFIG_TIMER_STATS
+
+extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
+ void *timerf, char * comm);
+
+static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
+{
+ timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
+ timer->function, timer->start_comm);
+}
+
+extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer,
+ void *addr);
+
+static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
+{
+ __timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0));
+}
+
+static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
+{
+ timer->start_site = NULL;
+}
+#else
+static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
+{
+}
+
+static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
+{
+}
+
+static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
+{
+}
+#endif
+
#endif