Move timekeeping code to timekeeping.c
Move the timekeeping code out of kernel/timer.c and into kernel/time/timekeeping.c. I made no cleanups or other changes in transit. [akpm@linux-foundation.org: build fix] Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
john stultz
Linus Torvalds
parent
329c8d84ca
commit
8524070b79
4 changed files with 479 additions and 459 deletions
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@ -119,6 +119,7 @@ extern void getnstimeofday(struct timespec *tv);
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extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
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extern int timekeeping_is_continuous(void);
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extern void update_wall_time(void);
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/**
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* timespec_to_ns - Convert timespec to nanoseconds
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@ -1,4 +1,4 @@
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obj-y += ntp.o clocksource.o jiffies.o timer_list.o
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obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o
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obj-$(CONFIG_GENERIC_CLOCKEVENTS) += clockevents.o
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obj-$(CONFIG_GENERIC_CLOCKEVENTS) += tick-common.o
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476
kernel/time/timekeeping.c
Normal file
476
kernel/time/timekeeping.c
Normal file
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@ -0,0 +1,476 @@
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/*
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* linux/kernel/time/timekeeping.c
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*
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* Kernel timekeeping code and accessor functions
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*
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* This code was moved from linux/kernel/timer.c.
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* Please see that file for copyright and history logs.
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*
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*/
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/percpu.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/sysdev.h>
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#include <linux/clocksource.h>
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#include <linux/jiffies.h>
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#include <linux/time.h>
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#include <linux/tick.h>
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/*
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* This read-write spinlock protects us from races in SMP while
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* playing with xtime and avenrun.
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*/
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__attribute__((weak)) __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
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EXPORT_SYMBOL(xtime_lock);
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/*
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* The current time
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* wall_to_monotonic is what we need to add to xtime (or xtime corrected
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* for sub jiffie times) to get to monotonic time. Monotonic is pegged
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* at zero at system boot time, so wall_to_monotonic will be negative,
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* however, we will ALWAYS keep the tv_nsec part positive so we can use
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* the usual normalization.
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*/
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struct timespec xtime __attribute__ ((aligned (16)));
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struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
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EXPORT_SYMBOL(xtime);
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static struct clocksource *clock; /* pointer to current clocksource */
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#ifdef CONFIG_GENERIC_TIME
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/**
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* __get_nsec_offset - Returns nanoseconds since last call to periodic_hook
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*
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* private function, must hold xtime_lock lock when being
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* called. Returns the number of nanoseconds since the
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* last call to update_wall_time() (adjusted by NTP scaling)
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*/
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static inline s64 __get_nsec_offset(void)
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{
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cycle_t cycle_now, cycle_delta;
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s64 ns_offset;
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/* read clocksource: */
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cycle_now = clocksource_read(clock);
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/* calculate the delta since the last update_wall_time: */
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cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
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/* convert to nanoseconds: */
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ns_offset = cyc2ns(clock, cycle_delta);
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return ns_offset;
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}
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/**
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* __get_realtime_clock_ts - Returns the time of day in a timespec
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* @ts: pointer to the timespec to be set
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*
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* Returns the time of day in a timespec. Used by
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* do_gettimeofday() and get_realtime_clock_ts().
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*/
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static inline void __get_realtime_clock_ts(struct timespec *ts)
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{
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unsigned long seq;
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s64 nsecs;
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do {
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seq = read_seqbegin(&xtime_lock);
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*ts = xtime;
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nsecs = __get_nsec_offset();
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} while (read_seqretry(&xtime_lock, seq));
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timespec_add_ns(ts, nsecs);
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}
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/**
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* getnstimeofday - Returns the time of day in a timespec
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* @ts: pointer to the timespec to be set
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*
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* Returns the time of day in a timespec.
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*/
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void getnstimeofday(struct timespec *ts)
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{
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__get_realtime_clock_ts(ts);
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}
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EXPORT_SYMBOL(getnstimeofday);
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/**
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* do_gettimeofday - Returns the time of day in a timeval
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* @tv: pointer to the timeval to be set
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*
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* NOTE: Users should be converted to using get_realtime_clock_ts()
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*/
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void do_gettimeofday(struct timeval *tv)
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{
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struct timespec now;
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__get_realtime_clock_ts(&now);
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tv->tv_sec = now.tv_sec;
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tv->tv_usec = now.tv_nsec/1000;
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}
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EXPORT_SYMBOL(do_gettimeofday);
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/**
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* do_settimeofday - Sets the time of day
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* @tv: pointer to the timespec variable containing the new time
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*
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* Sets the time of day to the new time and update NTP and notify hrtimers
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*/
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int do_settimeofday(struct timespec *tv)
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{
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unsigned long flags;
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time_t wtm_sec, sec = tv->tv_sec;
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long wtm_nsec, nsec = tv->tv_nsec;
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if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
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return -EINVAL;
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write_seqlock_irqsave(&xtime_lock, flags);
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nsec -= __get_nsec_offset();
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wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
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wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
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set_normalized_timespec(&xtime, sec, nsec);
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set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
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clock->error = 0;
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ntp_clear();
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update_vsyscall(&xtime, clock);
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write_sequnlock_irqrestore(&xtime_lock, flags);
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/* signal hrtimers about time change */
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clock_was_set();
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return 0;
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}
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EXPORT_SYMBOL(do_settimeofday);
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/**
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* change_clocksource - Swaps clocksources if a new one is available
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*
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* Accumulates current time interval and initializes new clocksource
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*/
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static void change_clocksource(void)
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{
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struct clocksource *new;
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cycle_t now;
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u64 nsec;
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new = clocksource_get_next();
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if (clock == new)
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return;
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now = clocksource_read(new);
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nsec = __get_nsec_offset();
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timespec_add_ns(&xtime, nsec);
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clock = new;
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clock->cycle_last = now;
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clock->error = 0;
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clock->xtime_nsec = 0;
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clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
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tick_clock_notify();
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printk(KERN_INFO "Time: %s clocksource has been installed.\n",
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clock->name);
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}
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#else
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static inline void change_clocksource(void) { }
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#endif
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/**
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* timekeeping_is_continuous - check to see if timekeeping is free running
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*/
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int timekeeping_is_continuous(void)
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{
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unsigned long seq;
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int ret;
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do {
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seq = read_seqbegin(&xtime_lock);
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ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
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} while (read_seqretry(&xtime_lock, seq));
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return ret;
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}
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/**
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* read_persistent_clock - Return time in seconds from the persistent clock.
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*
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* Weak dummy function for arches that do not yet support it.
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* Returns seconds from epoch using the battery backed persistent clock.
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* Returns zero if unsupported.
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*
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* XXX - Do be sure to remove it once all arches implement it.
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*/
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unsigned long __attribute__((weak)) read_persistent_clock(void)
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{
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return 0;
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}
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/*
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* timekeeping_init - Initializes the clocksource and common timekeeping values
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*/
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void __init timekeeping_init(void)
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{
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unsigned long flags;
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unsigned long sec = read_persistent_clock();
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write_seqlock_irqsave(&xtime_lock, flags);
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ntp_clear();
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clock = clocksource_get_next();
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clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
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clock->cycle_last = clocksource_read(clock);
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xtime.tv_sec = sec;
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xtime.tv_nsec = 0;
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set_normalized_timespec(&wall_to_monotonic,
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-xtime.tv_sec, -xtime.tv_nsec);
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write_sequnlock_irqrestore(&xtime_lock, flags);
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}
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/* flag for if timekeeping is suspended */
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static int timekeeping_suspended;
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/* time in seconds when suspend began */
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static unsigned long timekeeping_suspend_time;
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/**
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* timekeeping_resume - Resumes the generic timekeeping subsystem.
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* @dev: unused
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*
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* This is for the generic clocksource timekeeping.
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* xtime/wall_to_monotonic/jiffies/etc are
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* still managed by arch specific suspend/resume code.
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*/
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static int timekeeping_resume(struct sys_device *dev)
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{
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unsigned long flags;
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unsigned long now = read_persistent_clock();
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write_seqlock_irqsave(&xtime_lock, flags);
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if (now && (now > timekeeping_suspend_time)) {
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unsigned long sleep_length = now - timekeeping_suspend_time;
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xtime.tv_sec += sleep_length;
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wall_to_monotonic.tv_sec -= sleep_length;
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}
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/* re-base the last cycle value */
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clock->cycle_last = clocksource_read(clock);
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clock->error = 0;
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timekeeping_suspended = 0;
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write_sequnlock_irqrestore(&xtime_lock, flags);
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touch_softlockup_watchdog();
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clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
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/* Resume hrtimers */
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hres_timers_resume();
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return 0;
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}
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static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
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{
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unsigned long flags;
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write_seqlock_irqsave(&xtime_lock, flags);
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timekeeping_suspended = 1;
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timekeeping_suspend_time = read_persistent_clock();
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write_sequnlock_irqrestore(&xtime_lock, flags);
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clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
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return 0;
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}
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/* sysfs resume/suspend bits for timekeeping */
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static struct sysdev_class timekeeping_sysclass = {
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.resume = timekeeping_resume,
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.suspend = timekeeping_suspend,
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set_kset_name("timekeeping"),
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};
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static struct sys_device device_timer = {
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.id = 0,
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.cls = &timekeeping_sysclass,
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};
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static int __init timekeeping_init_device(void)
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{
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int error = sysdev_class_register(&timekeeping_sysclass);
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if (!error)
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error = sysdev_register(&device_timer);
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return error;
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}
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device_initcall(timekeeping_init_device);
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/*
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* If the error is already larger, we look ahead even further
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* to compensate for late or lost adjustments.
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*/
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static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
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s64 *offset)
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{
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s64 tick_error, i;
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u32 look_ahead, adj;
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s32 error2, mult;
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/*
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* Use the current error value to determine how much to look ahead.
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* The larger the error the slower we adjust for it to avoid problems
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* with losing too many ticks, otherwise we would overadjust and
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* produce an even larger error. The smaller the adjustment the
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* faster we try to adjust for it, as lost ticks can do less harm
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* here. This is tuned so that an error of about 1 msec is adusted
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* within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
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*/
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error2 = clock->error >> (TICK_LENGTH_SHIFT + 22 - 2 * SHIFT_HZ);
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error2 = abs(error2);
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for (look_ahead = 0; error2 > 0; look_ahead++)
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error2 >>= 2;
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/*
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* Now calculate the error in (1 << look_ahead) ticks, but first
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* remove the single look ahead already included in the error.
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*/
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tick_error = current_tick_length() >>
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(TICK_LENGTH_SHIFT - clock->shift + 1);
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tick_error -= clock->xtime_interval >> 1;
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error = ((error - tick_error) >> look_ahead) + tick_error;
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/* Finally calculate the adjustment shift value. */
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i = *interval;
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mult = 1;
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if (error < 0) {
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error = -error;
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*interval = -*interval;
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*offset = -*offset;
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mult = -1;
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}
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for (adj = 0; error > i; adj++)
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error >>= 1;
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*interval <<= adj;
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*offset <<= adj;
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return mult << adj;
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}
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/*
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* Adjust the multiplier to reduce the error value,
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* this is optimized for the most common adjustments of -1,0,1,
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* for other values we can do a bit more work.
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*/
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static void clocksource_adjust(struct clocksource *clock, s64 offset)
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{
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s64 error, interval = clock->cycle_interval;
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int adj;
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error = clock->error >> (TICK_LENGTH_SHIFT - clock->shift - 1);
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if (error > interval) {
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error >>= 2;
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if (likely(error <= interval))
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adj = 1;
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else
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adj = clocksource_bigadjust(error, &interval, &offset);
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} else if (error < -interval) {
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error >>= 2;
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if (likely(error >= -interval)) {
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adj = -1;
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interval = -interval;
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offset = -offset;
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} else
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adj = clocksource_bigadjust(error, &interval, &offset);
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} else
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return;
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clock->mult += adj;
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clock->xtime_interval += interval;
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clock->xtime_nsec -= offset;
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clock->error -= (interval - offset) <<
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(TICK_LENGTH_SHIFT - clock->shift);
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}
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/**
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* update_wall_time - Uses the current clocksource to increment the wall time
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*
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* Called from the timer interrupt, must hold a write on xtime_lock.
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*/
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void update_wall_time(void)
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{
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cycle_t offset;
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/* Make sure we're fully resumed: */
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if (unlikely(timekeeping_suspended))
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return;
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#ifdef CONFIG_GENERIC_TIME
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offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask;
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#else
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offset = clock->cycle_interval;
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#endif
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clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
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/* normally this loop will run just once, however in the
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* case of lost or late ticks, it will accumulate correctly.
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*/
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while (offset >= clock->cycle_interval) {
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/* accumulate one interval */
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clock->xtime_nsec += clock->xtime_interval;
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clock->cycle_last += clock->cycle_interval;
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offset -= clock->cycle_interval;
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if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
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clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
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xtime.tv_sec++;
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second_overflow();
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}
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/* interpolator bits */
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time_interpolator_update(clock->xtime_interval
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>> clock->shift);
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/* accumulate error between NTP and clock interval */
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clock->error += current_tick_length();
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clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
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}
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/* correct the clock when NTP error is too big */
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clocksource_adjust(clock, offset);
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/* store full nanoseconds into xtime */
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xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
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clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
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/* check to see if there is a new clocksource to use */
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change_clocksource();
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update_vsyscall(&xtime, clock);
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}
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459
kernel/timer.c
459
kernel/timer.c
|
|
@ -1,7 +1,7 @@
|
|||
/*
|
||||
* linux/kernel/timer.c
|
||||
*
|
||||
* Kernel internal timers, kernel timekeeping, basic process system calls
|
||||
* Kernel internal timers, basic process system calls
|
||||
*
|
||||
* Copyright (C) 1991, 1992 Linus Torvalds
|
||||
*
|
||||
|
|
@ -794,455 +794,6 @@ unsigned long next_timer_interrupt(void)
|
|||
|
||||
#endif
|
||||
|
||||
/******************************************************************/
|
||||
|
||||
/*
|
||||
* The current time
|
||||
* wall_to_monotonic is what we need to add to xtime (or xtime corrected
|
||||
* for sub jiffie times) to get to monotonic time. Monotonic is pegged
|
||||
* at zero at system boot time, so wall_to_monotonic will be negative,
|
||||
* however, we will ALWAYS keep the tv_nsec part positive so we can use
|
||||
* the usual normalization.
|
||||
*/
|
||||
struct timespec xtime __attribute__ ((aligned (16)));
|
||||
struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
|
||||
|
||||
EXPORT_SYMBOL(xtime);
|
||||
|
||||
|
||||
/* XXX - all of this timekeeping code should be later moved to time.c */
|
||||
#include <linux/clocksource.h>
|
||||
static struct clocksource *clock; /* pointer to current clocksource */
|
||||
|
||||
#ifdef CONFIG_GENERIC_TIME
|
||||
/**
|
||||
* __get_nsec_offset - Returns nanoseconds since last call to periodic_hook
|
||||
*
|
||||
* private function, must hold xtime_lock lock when being
|
||||
* called. Returns the number of nanoseconds since the
|
||||
* last call to update_wall_time() (adjusted by NTP scaling)
|
||||
*/
|
||||
static inline s64 __get_nsec_offset(void)
|
||||
{
|
||||
cycle_t cycle_now, cycle_delta;
|
||||
s64 ns_offset;
|
||||
|
||||
/* read clocksource: */
|
||||
cycle_now = clocksource_read(clock);
|
||||
|
||||
/* calculate the delta since the last update_wall_time: */
|
||||
cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
|
||||
|
||||
/* convert to nanoseconds: */
|
||||
ns_offset = cyc2ns(clock, cycle_delta);
|
||||
|
||||
return ns_offset;
|
||||
}
|
||||
|
||||
/**
|
||||
* __get_realtime_clock_ts - Returns the time of day in a timespec
|
||||
* @ts: pointer to the timespec to be set
|
||||
*
|
||||
* Returns the time of day in a timespec. Used by
|
||||
* do_gettimeofday() and get_realtime_clock_ts().
|
||||
*/
|
||||
static inline void __get_realtime_clock_ts(struct timespec *ts)
|
||||
{
|
||||
unsigned long seq;
|
||||
s64 nsecs;
|
||||
|
||||
do {
|
||||
seq = read_seqbegin(&xtime_lock);
|
||||
|
||||
*ts = xtime;
|
||||
nsecs = __get_nsec_offset();
|
||||
|
||||
} while (read_seqretry(&xtime_lock, seq));
|
||||
|
||||
timespec_add_ns(ts, nsecs);
|
||||
}
|
||||
|
||||
/**
|
||||
* getnstimeofday - Returns the time of day in a timespec
|
||||
* @ts: pointer to the timespec to be set
|
||||
*
|
||||
* Returns the time of day in a timespec.
|
||||
*/
|
||||
void getnstimeofday(struct timespec *ts)
|
||||
{
|
||||
__get_realtime_clock_ts(ts);
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL(getnstimeofday);
|
||||
|
||||
/**
|
||||
* do_gettimeofday - Returns the time of day in a timeval
|
||||
* @tv: pointer to the timeval to be set
|
||||
*
|
||||
* NOTE: Users should be converted to using get_realtime_clock_ts()
|
||||
*/
|
||||
void do_gettimeofday(struct timeval *tv)
|
||||
{
|
||||
struct timespec now;
|
||||
|
||||
__get_realtime_clock_ts(&now);
|
||||
tv->tv_sec = now.tv_sec;
|
||||
tv->tv_usec = now.tv_nsec/1000;
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL(do_gettimeofday);
|
||||
/**
|
||||
* do_settimeofday - Sets the time of day
|
||||
* @tv: pointer to the timespec variable containing the new time
|
||||
*
|
||||
* Sets the time of day to the new time and update NTP and notify hrtimers
|
||||
*/
|
||||
int do_settimeofday(struct timespec *tv)
|
||||
{
|
||||
unsigned long flags;
|
||||
time_t wtm_sec, sec = tv->tv_sec;
|
||||
long wtm_nsec, nsec = tv->tv_nsec;
|
||||
|
||||
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
|
||||
return -EINVAL;
|
||||
|
||||
write_seqlock_irqsave(&xtime_lock, flags);
|
||||
|
||||
nsec -= __get_nsec_offset();
|
||||
|
||||
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
|
||||
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
|
||||
|
||||
set_normalized_timespec(&xtime, sec, nsec);
|
||||
set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
|
||||
|
||||
clock->error = 0;
|
||||
ntp_clear();
|
||||
|
||||
update_vsyscall(&xtime, clock);
|
||||
|
||||
write_sequnlock_irqrestore(&xtime_lock, flags);
|
||||
|
||||
/* signal hrtimers about time change */
|
||||
clock_was_set();
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL(do_settimeofday);
|
||||
|
||||
/**
|
||||
* change_clocksource - Swaps clocksources if a new one is available
|
||||
*
|
||||
* Accumulates current time interval and initializes new clocksource
|
||||
*/
|
||||
static void change_clocksource(void)
|
||||
{
|
||||
struct clocksource *new;
|
||||
cycle_t now;
|
||||
u64 nsec;
|
||||
|
||||
new = clocksource_get_next();
|
||||
|
||||
if (clock == new)
|
||||
return;
|
||||
|
||||
now = clocksource_read(new);
|
||||
nsec = __get_nsec_offset();
|
||||
timespec_add_ns(&xtime, nsec);
|
||||
|
||||
clock = new;
|
||||
clock->cycle_last = now;
|
||||
|
||||
clock->error = 0;
|
||||
clock->xtime_nsec = 0;
|
||||
clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
|
||||
|
||||
tick_clock_notify();
|
||||
|
||||
printk(KERN_INFO "Time: %s clocksource has been installed.\n",
|
||||
clock->name);
|
||||
}
|
||||
#else
|
||||
static inline void change_clocksource(void) { }
|
||||
#endif
|
||||
|
||||
/**
|
||||
* timekeeping_is_continuous - check to see if timekeeping is free running
|
||||
*/
|
||||
int timekeeping_is_continuous(void)
|
||||
{
|
||||
unsigned long seq;
|
||||
int ret;
|
||||
|
||||
do {
|
||||
seq = read_seqbegin(&xtime_lock);
|
||||
|
||||
ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
|
||||
|
||||
} while (read_seqretry(&xtime_lock, seq));
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
/**
|
||||
* read_persistent_clock - Return time in seconds from the persistent clock.
|
||||
*
|
||||
* Weak dummy function for arches that do not yet support it.
|
||||
* Returns seconds from epoch using the battery backed persistent clock.
|
||||
* Returns zero if unsupported.
|
||||
*
|
||||
* XXX - Do be sure to remove it once all arches implement it.
|
||||
*/
|
||||
unsigned long __attribute__((weak)) read_persistent_clock(void)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* timekeeping_init - Initializes the clocksource and common timekeeping values
|
||||
*/
|
||||
void __init timekeeping_init(void)
|
||||
{
|
||||
unsigned long flags;
|
||||
unsigned long sec = read_persistent_clock();
|
||||
|
||||
write_seqlock_irqsave(&xtime_lock, flags);
|
||||
|
||||
ntp_clear();
|
||||
|
||||
clock = clocksource_get_next();
|
||||
clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
|
||||
clock->cycle_last = clocksource_read(clock);
|
||||
|
||||
xtime.tv_sec = sec;
|
||||
xtime.tv_nsec = 0;
|
||||
set_normalized_timespec(&wall_to_monotonic,
|
||||
-xtime.tv_sec, -xtime.tv_nsec);
|
||||
|
||||
write_sequnlock_irqrestore(&xtime_lock, flags);
|
||||
}
|
||||
|
||||
/* flag for if timekeeping is suspended */
|
||||
static int timekeeping_suspended;
|
||||
/* time in seconds when suspend began */
|
||||
static unsigned long timekeeping_suspend_time;
|
||||
|
||||
/**
|
||||
* timekeeping_resume - Resumes the generic timekeeping subsystem.
|
||||
* @dev: unused
|
||||
*
|
||||
* This is for the generic clocksource timekeeping.
|
||||
* xtime/wall_to_monotonic/jiffies/etc are
|
||||
* still managed by arch specific suspend/resume code.
|
||||
*/
|
||||
static int timekeeping_resume(struct sys_device *dev)
|
||||
{
|
||||
unsigned long flags;
|
||||
unsigned long now = read_persistent_clock();
|
||||
|
||||
write_seqlock_irqsave(&xtime_lock, flags);
|
||||
|
||||
if (now && (now > timekeeping_suspend_time)) {
|
||||
unsigned long sleep_length = now - timekeeping_suspend_time;
|
||||
|
||||
xtime.tv_sec += sleep_length;
|
||||
wall_to_monotonic.tv_sec -= sleep_length;
|
||||
}
|
||||
/* re-base the last cycle value */
|
||||
clock->cycle_last = clocksource_read(clock);
|
||||
clock->error = 0;
|
||||
timekeeping_suspended = 0;
|
||||
write_sequnlock_irqrestore(&xtime_lock, flags);
|
||||
|
||||
touch_softlockup_watchdog();
|
||||
|
||||
clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
|
||||
|
||||
/* Resume hrtimers */
|
||||
hres_timers_resume();
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
|
||||
{
|
||||
unsigned long flags;
|
||||
|
||||
write_seqlock_irqsave(&xtime_lock, flags);
|
||||
timekeeping_suspended = 1;
|
||||
timekeeping_suspend_time = read_persistent_clock();
|
||||
write_sequnlock_irqrestore(&xtime_lock, flags);
|
||||
|
||||
clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* sysfs resume/suspend bits for timekeeping */
|
||||
static struct sysdev_class timekeeping_sysclass = {
|
||||
.resume = timekeeping_resume,
|
||||
.suspend = timekeeping_suspend,
|
||||
set_kset_name("timekeeping"),
|
||||
};
|
||||
|
||||
static struct sys_device device_timer = {
|
||||
.id = 0,
|
||||
.cls = &timekeeping_sysclass,
|
||||
};
|
||||
|
||||
static int __init timekeeping_init_device(void)
|
||||
{
|
||||
int error = sysdev_class_register(&timekeeping_sysclass);
|
||||
if (!error)
|
||||
error = sysdev_register(&device_timer);
|
||||
return error;
|
||||
}
|
||||
|
||||
device_initcall(timekeeping_init_device);
|
||||
|
||||
/*
|
||||
* If the error is already larger, we look ahead even further
|
||||
* to compensate for late or lost adjustments.
|
||||
*/
|
||||
static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
|
||||
s64 *offset)
|
||||
{
|
||||
s64 tick_error, i;
|
||||
u32 look_ahead, adj;
|
||||
s32 error2, mult;
|
||||
|
||||
/*
|
||||
* Use the current error value to determine how much to look ahead.
|
||||
* The larger the error the slower we adjust for it to avoid problems
|
||||
* with losing too many ticks, otherwise we would overadjust and
|
||||
* produce an even larger error. The smaller the adjustment the
|
||||
* faster we try to adjust for it, as lost ticks can do less harm
|
||||
* here. This is tuned so that an error of about 1 msec is adusted
|
||||
* within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
|
||||
*/
|
||||
error2 = clock->error >> (TICK_LENGTH_SHIFT + 22 - 2 * SHIFT_HZ);
|
||||
error2 = abs(error2);
|
||||
for (look_ahead = 0; error2 > 0; look_ahead++)
|
||||
error2 >>= 2;
|
||||
|
||||
/*
|
||||
* Now calculate the error in (1 << look_ahead) ticks, but first
|
||||
* remove the single look ahead already included in the error.
|
||||
*/
|
||||
tick_error = current_tick_length() >>
|
||||
(TICK_LENGTH_SHIFT - clock->shift + 1);
|
||||
tick_error -= clock->xtime_interval >> 1;
|
||||
error = ((error - tick_error) >> look_ahead) + tick_error;
|
||||
|
||||
/* Finally calculate the adjustment shift value. */
|
||||
i = *interval;
|
||||
mult = 1;
|
||||
if (error < 0) {
|
||||
error = -error;
|
||||
*interval = -*interval;
|
||||
*offset = -*offset;
|
||||
mult = -1;
|
||||
}
|
||||
for (adj = 0; error > i; adj++)
|
||||
error >>= 1;
|
||||
|
||||
*interval <<= adj;
|
||||
*offset <<= adj;
|
||||
return mult << adj;
|
||||
}
|
||||
|
||||
/*
|
||||
* Adjust the multiplier to reduce the error value,
|
||||
* this is optimized for the most common adjustments of -1,0,1,
|
||||
* for other values we can do a bit more work.
|
||||
*/
|
||||
static void clocksource_adjust(struct clocksource *clock, s64 offset)
|
||||
{
|
||||
s64 error, interval = clock->cycle_interval;
|
||||
int adj;
|
||||
|
||||
error = clock->error >> (TICK_LENGTH_SHIFT - clock->shift - 1);
|
||||
if (error > interval) {
|
||||
error >>= 2;
|
||||
if (likely(error <= interval))
|
||||
adj = 1;
|
||||
else
|
||||
adj = clocksource_bigadjust(error, &interval, &offset);
|
||||
} else if (error < -interval) {
|
||||
error >>= 2;
|
||||
if (likely(error >= -interval)) {
|
||||
adj = -1;
|
||||
interval = -interval;
|
||||
offset = -offset;
|
||||
} else
|
||||
adj = clocksource_bigadjust(error, &interval, &offset);
|
||||
} else
|
||||
return;
|
||||
|
||||
clock->mult += adj;
|
||||
clock->xtime_interval += interval;
|
||||
clock->xtime_nsec -= offset;
|
||||
clock->error -= (interval - offset) <<
|
||||
(TICK_LENGTH_SHIFT - clock->shift);
|
||||
}
|
||||
|
||||
/**
|
||||
* update_wall_time - Uses the current clocksource to increment the wall time
|
||||
*
|
||||
* Called from the timer interrupt, must hold a write on xtime_lock.
|
||||
*/
|
||||
static void update_wall_time(void)
|
||||
{
|
||||
cycle_t offset;
|
||||
|
||||
/* Make sure we're fully resumed: */
|
||||
if (unlikely(timekeeping_suspended))
|
||||
return;
|
||||
|
||||
#ifdef CONFIG_GENERIC_TIME
|
||||
offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask;
|
||||
#else
|
||||
offset = clock->cycle_interval;
|
||||
#endif
|
||||
clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
|
||||
|
||||
/* normally this loop will run just once, however in the
|
||||
* case of lost or late ticks, it will accumulate correctly.
|
||||
*/
|
||||
while (offset >= clock->cycle_interval) {
|
||||
/* accumulate one interval */
|
||||
clock->xtime_nsec += clock->xtime_interval;
|
||||
clock->cycle_last += clock->cycle_interval;
|
||||
offset -= clock->cycle_interval;
|
||||
|
||||
if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
|
||||
clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
|
||||
xtime.tv_sec++;
|
||||
second_overflow();
|
||||
}
|
||||
|
||||
/* interpolator bits */
|
||||
time_interpolator_update(clock->xtime_interval
|
||||
>> clock->shift);
|
||||
|
||||
/* accumulate error between NTP and clock interval */
|
||||
clock->error += current_tick_length();
|
||||
clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
|
||||
}
|
||||
|
||||
/* correct the clock when NTP error is too big */
|
||||
clocksource_adjust(clock, offset);
|
||||
|
||||
/* store full nanoseconds into xtime */
|
||||
xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
|
||||
clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
|
||||
|
||||
/* check to see if there is a new clocksource to use */
|
||||
change_clocksource();
|
||||
update_vsyscall(&xtime, clock);
|
||||
}
|
||||
|
||||
/*
|
||||
* 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.
|
||||
|
|
@ -1305,14 +856,6 @@ static inline void calc_load(unsigned long ticks)
|
|||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* This read-write spinlock protects us from races in SMP while
|
||||
* playing with xtime and avenrun.
|
||||
*/
|
||||
__attribute__((weak)) __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
|
||||
|
||||
EXPORT_SYMBOL(xtime_lock);
|
||||
|
||||
/*
|
||||
* This function runs timers and the timer-tq in bottom half context.
|
||||
*/
|
||||
|
|
|
|||
Loading…
Reference in a new issue