[PATCH] hrtimer: hrtimer core code

hrtimer subsystem core.  It is initialized at bootup and expired by the timer
interrupt, but is otherwise not utilized by any other subsystem yet.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/hrtimer.h

+/*
+ *  include/linux/hrtimer.h
+ *
+ *  hrtimers - High-resolution kernel timers
+ *
+ *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
+ *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
+ *
+ *  data type definitions, declarations, prototypes
+ *
+ *  Started by: Thomas Gleixner and Ingo Molnar
+ *
+ *  For licencing details see kernel-base/COPYING
+ */
+#ifndef _LINUX_HRTIMER_H
+#define _LINUX_HRTIMER_H
+
+#include <linux/rbtree.h>
+#include <linux/ktime.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+
+/*
+ * Mode arguments of xxx_hrtimer functions:
+ */
+enum hrtimer_mode {
+	HRTIMER_ABS,	/* Time value is absolute */
+	HRTIMER_REL,	/* Time value is relative to now */
+};
+
+enum hrtimer_restart {
+	HRTIMER_NORESTART,
+	HRTIMER_RESTART,
+};
+
+/*
+ * Timer states:
+ */
+enum hrtimer_state {
+	HRTIMER_INACTIVE,	/* Timer is inactive */
+	HRTIMER_EXPIRED,		/* Timer is expired */
+	HRTIMER_PENDING,		/* Timer is pending */
+};
+
+struct hrtimer_base;
+
+/**
+ * struct hrtimer - the basic hrtimer structure
+ *
+ * @node:	red black tree node for time ordered insertion
+ * @list:	list head for easier access to the time ordered list,
+ *		without walking the red black tree.
+ * @expires:	the absolute expiry time in the hrtimers internal
+ *		representation. The time is related to the clock on
+ *		which the timer is based.
+ * @state:	state of the timer
+ * @function:	timer expiry callback function
+ * @data:	argument for the callback function
+ * @base:	pointer to the timer base (per cpu and per clock)
+ *
+ * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
+ */
+struct hrtimer {
+	struct rb_node		node;
+	struct list_head	list;
+	ktime_t			expires;
+	enum hrtimer_state	state;
+	int			(*function)(void *);
+	void			*data;
+	struct hrtimer_base	*base;
+};
+
+/**
+ * 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
+ * @active:	red black tree root node for the active timers
+ * @pending:	list of pending timers for simple time ordered access
+ * @resolution:	the resolution of the clock, in nanoseconds
+ * @get_time:	function to retrieve the current time of the clock
+ * @curr_timer:	the timer which is executing a callback right now
+ */
+struct hrtimer_base {
+	clockid_t		index;
+	spinlock_t		lock;
+	struct rb_root		active;
+	struct list_head	pending;
+	unsigned long		resolution;
+	ktime_t			(*get_time)(void);
+	struct hrtimer		*curr_timer;
+};
+
+/* Exported timer functions: */
+
+/* Initialize timers: */
+extern void hrtimer_init(struct hrtimer *timer, const clockid_t which_clock);
+extern void hrtimer_rebase(struct hrtimer *timer, const clockid_t which_clock);
+
+
+/* Basic timer operations: */
+extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
+			 const enum hrtimer_mode mode);
+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)
+
+/* 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);
+
+static inline int hrtimer_active(const struct hrtimer *timer)
+{
+	return timer->state == HRTIMER_PENDING;
+}
+
+/* Forward a hrtimer so it expires after now: */
+extern unsigned long hrtimer_forward(struct hrtimer *timer,
+				     const ktime_t interval);
+
+/* Soft interrupt function to run the hrtimer queues: */
+extern void hrtimer_run_queues(void);
+
+/* Bootup initialization: */
+extern void __init hrtimers_init(void);
+
+#endif

include/linux/ktime.h

@@ -266,4 +266,19 @@ static inline u64 ktime_to_ns(const ktime_t kt)
 
 #endif
 
+/*
+ * 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_REALTIME_RES	(NSEC_PER_SEC/HZ)
+#define KTIME_MONOTONIC_RES	(NSEC_PER_SEC/HZ)
+
+/* Get the monotonic time in timespec format: */
+extern void ktime_get_ts(struct timespec *ts);
+
+/* Get the real (wall-) time in timespec format: */
+#define ktime_get_real_ts(ts)	getnstimeofday(ts)
+
 #endif

init/main.c

@@ -485,6 +485,7 @@ asmlinkage void __init start_kernel(void)
 	init_IRQ();
 	pidhash_init();
 	init_timers();
+	hrtimers_init();
 	softirq_init();
 	time_init();
 

kernel/Makefile

@@ -7,7 +7,8 @@ obj-y     = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
 	    sysctl.o capability.o ptrace.o timer.o user.o \
 	    signal.o sys.o kmod.o workqueue.o pid.o \
 	    rcupdate.o intermodule.o extable.o params.o posix-timers.o \
-	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o
+	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
+	    hrtimer.o
 
 obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
 obj-$(CONFIG_FUTEX) += futex.o

kernel/timer.c

@@ -858,6 +858,7 @@ static void run_timer_softirq(struct softirq_action *h)
 {
 	tvec_base_t *base = &__get_cpu_var(tvec_bases);
 
+ 	hrtimer_run_queues();
 	if (time_after_eq(jiffies, base->timer_jiffies))
 		__run_timers(base);
 }