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![Viresh Kumar](/assets/img/avatar_default.png)
There are only two users of get_nohz_timer_target(): timer and hrtimer. Both call it under same circumstances, i.e. #ifdef CONFIG_NO_HZ_COMMON if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu)) return get_nohz_timer_target(); #endif So, it makes more sense to get all this as part of get_nohz_timer_target() instead of duplicating code at two places. For this another parameter is required to be passed to this routine, pinned. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: fweisbec@gmail.com Cc: peterz@infradead.org Link: http://lkml.kernel.org/r/1e1b53537217d58d48c2d7a222a9c3ac47d5b64c.1395140107.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
1892 lines
48 KiB
C
1892 lines
48 KiB
C
/*
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* linux/kernel/hrtimer.c
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*
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* Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
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* Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
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* Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner
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*
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* High-resolution kernel timers
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*
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* In contrast to the low-resolution timeout API implemented in
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* kernel/timer.c, hrtimers provide finer resolution and accuracy
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* depending on system configuration and capabilities.
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*
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* These timers are currently used for:
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* - itimers
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* - POSIX timers
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* - nanosleep
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* - precise in-kernel timing
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*
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* Started by: Thomas Gleixner and Ingo Molnar
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*
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* Credits:
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* based on kernel/timer.c
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*
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* Help, testing, suggestions, bugfixes, improvements were
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* provided by:
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*
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* George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
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* et. al.
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*
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* For licencing details see kernel-base/COPYING
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*/
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#include <linux/cpu.h>
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#include <linux/export.h>
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#include <linux/percpu.h>
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#include <linux/hrtimer.h>
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#include <linux/notifier.h>
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#include <linux/syscalls.h>
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#include <linux/kallsyms.h>
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#include <linux/interrupt.h>
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#include <linux/tick.h>
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#include <linux/seq_file.h>
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#include <linux/err.h>
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#include <linux/debugobjects.h>
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#include <linux/sched.h>
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#include <linux/sched/sysctl.h>
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#include <linux/sched/rt.h>
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#include <linux/sched/deadline.h>
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#include <linux/timer.h>
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#include <linux/freezer.h>
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#include <asm/uaccess.h>
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#include <trace/events/timer.h>
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/*
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* The timer bases:
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*
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* There are more clockids then hrtimer bases. Thus, we index
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* into the timer bases by the hrtimer_base_type enum. When trying
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* to reach a base using a clockid, hrtimer_clockid_to_base()
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* is used to convert from clockid to the proper hrtimer_base_type.
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*/
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DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
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{
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.lock = __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases.lock),
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.clock_base =
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{
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{
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.index = HRTIMER_BASE_MONOTONIC,
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.clockid = CLOCK_MONOTONIC,
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.get_time = &ktime_get,
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.resolution = KTIME_LOW_RES,
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},
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{
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.index = HRTIMER_BASE_REALTIME,
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.clockid = CLOCK_REALTIME,
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.get_time = &ktime_get_real,
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.resolution = KTIME_LOW_RES,
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},
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{
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.index = HRTIMER_BASE_BOOTTIME,
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.clockid = CLOCK_BOOTTIME,
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.get_time = &ktime_get_boottime,
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.resolution = KTIME_LOW_RES,
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},
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{
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.index = HRTIMER_BASE_TAI,
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.clockid = CLOCK_TAI,
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.get_time = &ktime_get_clocktai,
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.resolution = KTIME_LOW_RES,
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},
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}
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};
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static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
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[CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
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[CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
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[CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
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[CLOCK_TAI] = HRTIMER_BASE_TAI,
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};
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static inline int hrtimer_clockid_to_base(clockid_t clock_id)
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{
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return hrtimer_clock_to_base_table[clock_id];
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}
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/*
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* Get the coarse grained time at the softirq based on xtime and
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* wall_to_monotonic.
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*/
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static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
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{
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ktime_t xtim, mono, boot;
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struct timespec xts, tom, slp;
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s32 tai_offset;
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get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp);
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tai_offset = timekeeping_get_tai_offset();
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xtim = timespec_to_ktime(xts);
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mono = ktime_add(xtim, timespec_to_ktime(tom));
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boot = ktime_add(mono, timespec_to_ktime(slp));
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base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
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base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
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base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
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base->clock_base[HRTIMER_BASE_TAI].softirq_time =
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ktime_add(xtim, ktime_set(tai_offset, 0));
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}
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/*
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* Functions and macros which are different for UP/SMP systems are kept in a
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* single place
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*/
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#ifdef CONFIG_SMP
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/*
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* We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
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* means that all timers which are tied to this base via timer->base are
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* locked, and the base itself is locked too.
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*
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* So __run_timers/migrate_timers can safely modify all timers which could
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* be found on the lists/queues.
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*
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* When the timer's base is locked, and the timer removed from list, it is
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* possible to set timer->base = NULL and drop the lock: the timer remains
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* locked.
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*/
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static
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struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
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unsigned long *flags)
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{
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struct hrtimer_clock_base *base;
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for (;;) {
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base = timer->base;
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if (likely(base != NULL)) {
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raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
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if (likely(base == timer->base))
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return base;
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/* The timer has migrated to another CPU: */
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raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
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}
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cpu_relax();
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}
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}
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/*
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* With HIGHRES=y we do not migrate the timer when it is expiring
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* before the next event on the target cpu because we cannot reprogram
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* the target cpu hardware and we would cause it to fire late.
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*
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* Called with cpu_base->lock of target cpu held.
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*/
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static int
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hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
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{
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#ifdef CONFIG_HIGH_RES_TIMERS
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ktime_t expires;
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if (!new_base->cpu_base->hres_active)
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return 0;
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expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
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return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
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#else
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return 0;
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#endif
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}
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/*
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* Switch the timer base to the current CPU when possible.
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*/
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static inline struct hrtimer_clock_base *
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switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
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int pinned)
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{
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struct hrtimer_clock_base *new_base;
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struct hrtimer_cpu_base *new_cpu_base;
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int this_cpu = smp_processor_id();
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int cpu = get_nohz_timer_target(pinned);
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int basenum = base->index;
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again:
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new_cpu_base = &per_cpu(hrtimer_bases, cpu);
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new_base = &new_cpu_base->clock_base[basenum];
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if (base != new_base) {
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/*
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* We are trying to move timer to new_base.
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* However we can't change timer's base while it is running,
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* so we keep it on the same CPU. No hassle vs. reprogramming
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* the event source in the high resolution case. The softirq
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* code will take care of this when the timer function has
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* completed. There is no conflict as we hold the lock until
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* the timer is enqueued.
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*/
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if (unlikely(hrtimer_callback_running(timer)))
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return base;
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/* See the comment in lock_timer_base() */
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timer->base = NULL;
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raw_spin_unlock(&base->cpu_base->lock);
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raw_spin_lock(&new_base->cpu_base->lock);
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if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
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cpu = this_cpu;
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raw_spin_unlock(&new_base->cpu_base->lock);
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raw_spin_lock(&base->cpu_base->lock);
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timer->base = base;
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goto again;
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}
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timer->base = new_base;
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}
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return new_base;
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}
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#else /* CONFIG_SMP */
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static inline struct hrtimer_clock_base *
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lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
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{
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struct hrtimer_clock_base *base = timer->base;
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raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
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return base;
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}
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# define switch_hrtimer_base(t, b, p) (b)
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#endif /* !CONFIG_SMP */
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/*
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* Functions for the union type storage format of ktime_t which are
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* too large for inlining:
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*/
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#if BITS_PER_LONG < 64
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# ifndef CONFIG_KTIME_SCALAR
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/**
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* ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
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* @kt: addend
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* @nsec: the scalar nsec value to add
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*
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* Returns the sum of kt and nsec in ktime_t format
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*/
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ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
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{
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ktime_t tmp;
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if (likely(nsec < NSEC_PER_SEC)) {
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tmp.tv64 = nsec;
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} else {
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unsigned long rem = do_div(nsec, NSEC_PER_SEC);
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/* Make sure nsec fits into long */
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if (unlikely(nsec > KTIME_SEC_MAX))
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return (ktime_t){ .tv64 = KTIME_MAX };
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tmp = ktime_set((long)nsec, rem);
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}
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return ktime_add(kt, tmp);
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}
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EXPORT_SYMBOL_GPL(ktime_add_ns);
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/**
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* ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
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* @kt: minuend
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* @nsec: the scalar nsec value to subtract
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*
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* Returns the subtraction of @nsec from @kt in ktime_t format
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*/
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ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
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{
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ktime_t tmp;
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if (likely(nsec < NSEC_PER_SEC)) {
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tmp.tv64 = nsec;
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} else {
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unsigned long rem = do_div(nsec, NSEC_PER_SEC);
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tmp = ktime_set((long)nsec, rem);
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}
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return ktime_sub(kt, tmp);
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}
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EXPORT_SYMBOL_GPL(ktime_sub_ns);
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# endif /* !CONFIG_KTIME_SCALAR */
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/*
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* Divide a ktime value by a nanosecond value
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*/
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u64 ktime_divns(const ktime_t kt, s64 div)
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{
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u64 dclc;
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int sft = 0;
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dclc = ktime_to_ns(kt);
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/* Make sure the divisor is less than 2^32: */
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while (div >> 32) {
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sft++;
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div >>= 1;
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}
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dclc >>= sft;
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do_div(dclc, (unsigned long) div);
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return dclc;
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}
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#endif /* BITS_PER_LONG >= 64 */
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/*
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* Add two ktime values and do a safety check for overflow:
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*/
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ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
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{
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ktime_t res = ktime_add(lhs, rhs);
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/*
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* We use KTIME_SEC_MAX here, the maximum timeout which we can
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* return to user space in a timespec:
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*/
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if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
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res = ktime_set(KTIME_SEC_MAX, 0);
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return res;
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}
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EXPORT_SYMBOL_GPL(ktime_add_safe);
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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static struct debug_obj_descr hrtimer_debug_descr;
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static void *hrtimer_debug_hint(void *addr)
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{
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return ((struct hrtimer *) addr)->function;
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}
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/*
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* fixup_init is called when:
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* - an active object is initialized
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*/
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static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
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{
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struct hrtimer *timer = addr;
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switch (state) {
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case ODEBUG_STATE_ACTIVE:
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hrtimer_cancel(timer);
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debug_object_init(timer, &hrtimer_debug_descr);
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return 1;
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default:
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return 0;
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}
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}
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/*
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* fixup_activate is called when:
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* - an active object is activated
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* - an unknown object is activated (might be a statically initialized object)
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*/
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static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
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{
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switch (state) {
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case ODEBUG_STATE_NOTAVAILABLE:
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WARN_ON_ONCE(1);
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return 0;
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case ODEBUG_STATE_ACTIVE:
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WARN_ON(1);
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default:
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return 0;
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}
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}
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/*
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* fixup_free is called when:
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* - an active object is freed
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*/
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static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
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{
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struct hrtimer *timer = addr;
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switch (state) {
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case ODEBUG_STATE_ACTIVE:
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hrtimer_cancel(timer);
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debug_object_free(timer, &hrtimer_debug_descr);
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return 1;
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default:
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return 0;
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}
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}
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static struct debug_obj_descr hrtimer_debug_descr = {
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.name = "hrtimer",
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.debug_hint = hrtimer_debug_hint,
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.fixup_init = hrtimer_fixup_init,
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.fixup_activate = hrtimer_fixup_activate,
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.fixup_free = hrtimer_fixup_free,
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};
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static inline void debug_hrtimer_init(struct hrtimer *timer)
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{
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debug_object_init(timer, &hrtimer_debug_descr);
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}
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static inline void debug_hrtimer_activate(struct hrtimer *timer)
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{
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debug_object_activate(timer, &hrtimer_debug_descr);
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}
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static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
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{
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debug_object_deactivate(timer, &hrtimer_debug_descr);
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}
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static inline void debug_hrtimer_free(struct hrtimer *timer)
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{
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debug_object_free(timer, &hrtimer_debug_descr);
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}
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static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
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enum hrtimer_mode mode);
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void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
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enum hrtimer_mode mode)
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{
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debug_object_init_on_stack(timer, &hrtimer_debug_descr);
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__hrtimer_init(timer, clock_id, mode);
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}
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EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
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void destroy_hrtimer_on_stack(struct hrtimer *timer)
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{
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debug_object_free(timer, &hrtimer_debug_descr);
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}
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|
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#else
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static inline void debug_hrtimer_init(struct hrtimer *timer) { }
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static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
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static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
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#endif
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|
|
static inline void
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debug_init(struct hrtimer *timer, clockid_t clockid,
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enum hrtimer_mode mode)
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{
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debug_hrtimer_init(timer);
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trace_hrtimer_init(timer, clockid, mode);
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}
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|
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static inline void debug_activate(struct hrtimer *timer)
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{
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debug_hrtimer_activate(timer);
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trace_hrtimer_start(timer);
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}
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static inline void debug_deactivate(struct hrtimer *timer)
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{
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debug_hrtimer_deactivate(timer);
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trace_hrtimer_cancel(timer);
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}
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|
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/* High resolution timer related functions */
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#ifdef CONFIG_HIGH_RES_TIMERS
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|
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/*
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* High resolution timer enabled ?
|
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*/
|
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static int hrtimer_hres_enabled __read_mostly = 1;
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|
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/*
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* Enable / Disable high resolution mode
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*/
|
|
static int __init setup_hrtimer_hres(char *str)
|
|
{
|
|
if (!strcmp(str, "off"))
|
|
hrtimer_hres_enabled = 0;
|
|
else if (!strcmp(str, "on"))
|
|
hrtimer_hres_enabled = 1;
|
|
else
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
__setup("highres=", setup_hrtimer_hres);
|
|
|
|
/*
|
|
* hrtimer_high_res_enabled - query, if the highres mode is enabled
|
|
*/
|
|
static inline int hrtimer_is_hres_enabled(void)
|
|
{
|
|
return hrtimer_hres_enabled;
|
|
}
|
|
|
|
/*
|
|
* Is the high resolution mode active ?
|
|
*/
|
|
static inline int hrtimer_hres_active(void)
|
|
{
|
|
return __this_cpu_read(hrtimer_bases.hres_active);
|
|
}
|
|
|
|
/*
|
|
* Reprogram the event source with checking both queues for the
|
|
* next event
|
|
* Called with interrupts disabled and base->lock held
|
|
*/
|
|
static void
|
|
hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
|
|
{
|
|
int i;
|
|
struct hrtimer_clock_base *base = cpu_base->clock_base;
|
|
ktime_t expires, expires_next;
|
|
|
|
expires_next.tv64 = KTIME_MAX;
|
|
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
|
|
struct hrtimer *timer;
|
|
struct timerqueue_node *next;
|
|
|
|
next = timerqueue_getnext(&base->active);
|
|
if (!next)
|
|
continue;
|
|
timer = container_of(next, struct hrtimer, node);
|
|
|
|
expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
|
|
/*
|
|
* clock_was_set() has changed base->offset so the
|
|
* result might be negative. Fix it up to prevent a
|
|
* false positive in clockevents_program_event()
|
|
*/
|
|
if (expires.tv64 < 0)
|
|
expires.tv64 = 0;
|
|
if (expires.tv64 < expires_next.tv64)
|
|
expires_next = expires;
|
|
}
|
|
|
|
if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
|
|
return;
|
|
|
|
cpu_base->expires_next.tv64 = expires_next.tv64;
|
|
|
|
if (cpu_base->expires_next.tv64 != KTIME_MAX)
|
|
tick_program_event(cpu_base->expires_next, 1);
|
|
}
|
|
|
|
/*
|
|
* Shared reprogramming for clock_realtime and clock_monotonic
|
|
*
|
|
* When a timer is enqueued and expires earlier than the already enqueued
|
|
* timers, we have to check, whether it expires earlier than the timer for
|
|
* which the clock event device was armed.
|
|
*
|
|
* Called with interrupts disabled and base->cpu_base.lock held
|
|
*/
|
|
static int hrtimer_reprogram(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
|
|
ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
|
|
int res;
|
|
|
|
WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
|
|
|
|
/*
|
|
* When the callback is running, we do not reprogram the clock event
|
|
* device. The timer callback is either running on a different CPU or
|
|
* the callback is executed in the hrtimer_interrupt context. The
|
|
* reprogramming is handled either by the softirq, which called the
|
|
* callback or at the end of the hrtimer_interrupt.
|
|
*/
|
|
if (hrtimer_callback_running(timer))
|
|
return 0;
|
|
|
|
/*
|
|
* CLOCK_REALTIME timer might be requested with an absolute
|
|
* expiry time which is less than base->offset. Nothing wrong
|
|
* about that, just avoid to call into the tick code, which
|
|
* has now objections against negative expiry values.
|
|
*/
|
|
if (expires.tv64 < 0)
|
|
return -ETIME;
|
|
|
|
if (expires.tv64 >= cpu_base->expires_next.tv64)
|
|
return 0;
|
|
|
|
/*
|
|
* If a hang was detected in the last timer interrupt then we
|
|
* do not schedule a timer which is earlier than the expiry
|
|
* which we enforced in the hang detection. We want the system
|
|
* to make progress.
|
|
*/
|
|
if (cpu_base->hang_detected)
|
|
return 0;
|
|
|
|
/*
|
|
* Clockevents returns -ETIME, when the event was in the past.
|
|
*/
|
|
res = tick_program_event(expires, 0);
|
|
if (!IS_ERR_VALUE(res))
|
|
cpu_base->expires_next = expires;
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
* Initialize the high resolution related parts of cpu_base
|
|
*/
|
|
static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
|
|
{
|
|
base->expires_next.tv64 = KTIME_MAX;
|
|
base->hres_active = 0;
|
|
}
|
|
|
|
/*
|
|
* When High resolution timers are active, try to reprogram. Note, that in case
|
|
* the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
|
|
* check happens. The timer gets enqueued into the rbtree. The reprogramming
|
|
* and expiry check is done in the hrtimer_interrupt or in the softirq.
|
|
*/
|
|
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
return base->cpu_base->hres_active && hrtimer_reprogram(timer, base);
|
|
}
|
|
|
|
static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
|
|
{
|
|
ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
|
|
ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
|
|
ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
|
|
|
|
return ktime_get_update_offsets(offs_real, offs_boot, offs_tai);
|
|
}
|
|
|
|
/*
|
|
* Retrigger next event is called after clock was set
|
|
*
|
|
* Called with interrupts disabled via on_each_cpu()
|
|
*/
|
|
static void retrigger_next_event(void *arg)
|
|
{
|
|
struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases);
|
|
|
|
if (!hrtimer_hres_active())
|
|
return;
|
|
|
|
raw_spin_lock(&base->lock);
|
|
hrtimer_update_base(base);
|
|
hrtimer_force_reprogram(base, 0);
|
|
raw_spin_unlock(&base->lock);
|
|
}
|
|
|
|
/*
|
|
* Switch to high resolution mode
|
|
*/
|
|
static int hrtimer_switch_to_hres(void)
|
|
{
|
|
int i, cpu = smp_processor_id();
|
|
struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
|
|
unsigned long flags;
|
|
|
|
if (base->hres_active)
|
|
return 1;
|
|
|
|
local_irq_save(flags);
|
|
|
|
if (tick_init_highres()) {
|
|
local_irq_restore(flags);
|
|
printk(KERN_WARNING "Could not switch to high resolution "
|
|
"mode on CPU %d\n", cpu);
|
|
return 0;
|
|
}
|
|
base->hres_active = 1;
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
|
|
base->clock_base[i].resolution = KTIME_HIGH_RES;
|
|
|
|
tick_setup_sched_timer();
|
|
/* "Retrigger" the interrupt to get things going */
|
|
retrigger_next_event(NULL);
|
|
local_irq_restore(flags);
|
|
return 1;
|
|
}
|
|
|
|
static void clock_was_set_work(struct work_struct *work)
|
|
{
|
|
clock_was_set();
|
|
}
|
|
|
|
static DECLARE_WORK(hrtimer_work, clock_was_set_work);
|
|
|
|
/*
|
|
* Called from timekeeping and resume code to reprogramm the hrtimer
|
|
* interrupt device on all cpus.
|
|
*/
|
|
void clock_was_set_delayed(void)
|
|
{
|
|
schedule_work(&hrtimer_work);
|
|
}
|
|
|
|
#else
|
|
|
|
static inline int hrtimer_hres_active(void) { return 0; }
|
|
static inline int hrtimer_is_hres_enabled(void) { return 0; }
|
|
static inline int hrtimer_switch_to_hres(void) { return 0; }
|
|
static inline void
|
|
hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
|
|
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
|
|
static inline void retrigger_next_event(void *arg) { }
|
|
|
|
#endif /* CONFIG_HIGH_RES_TIMERS */
|
|
|
|
/*
|
|
* Clock realtime was set
|
|
*
|
|
* Change the offset of the realtime clock vs. the monotonic
|
|
* clock.
|
|
*
|
|
* We might have to reprogram the high resolution timer interrupt. On
|
|
* SMP we call the architecture specific code to retrigger _all_ high
|
|
* resolution timer interrupts. On UP we just disable interrupts and
|
|
* call the high resolution interrupt code.
|
|
*/
|
|
void clock_was_set(void)
|
|
{
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
/* Retrigger the CPU local events everywhere */
|
|
on_each_cpu(retrigger_next_event, NULL, 1);
|
|
#endif
|
|
timerfd_clock_was_set();
|
|
}
|
|
|
|
/*
|
|
* During resume we might have to reprogram the high resolution timer
|
|
* interrupt on all online CPUs. However, all other CPUs will be
|
|
* stopped with IRQs interrupts disabled so the clock_was_set() call
|
|
* must be deferred.
|
|
*/
|
|
void hrtimers_resume(void)
|
|
{
|
|
WARN_ONCE(!irqs_disabled(),
|
|
KERN_INFO "hrtimers_resume() called with IRQs enabled!");
|
|
|
|
/* Retrigger on the local CPU */
|
|
retrigger_next_event(NULL);
|
|
/* And schedule a retrigger for all others */
|
|
clock_was_set_delayed();
|
|
}
|
|
|
|
static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
|
|
{
|
|
#ifdef CONFIG_TIMER_STATS
|
|
if (timer->start_site)
|
|
return;
|
|
timer->start_site = __builtin_return_address(0);
|
|
memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
|
|
timer->start_pid = current->pid;
|
|
#endif
|
|
}
|
|
|
|
static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
|
|
{
|
|
#ifdef CONFIG_TIMER_STATS
|
|
timer->start_site = NULL;
|
|
#endif
|
|
}
|
|
|
|
static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
|
|
{
|
|
#ifdef CONFIG_TIMER_STATS
|
|
if (likely(!timer_stats_active))
|
|
return;
|
|
timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
|
|
timer->function, timer->start_comm, 0);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Counterpart to lock_hrtimer_base above:
|
|
*/
|
|
static inline
|
|
void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
|
|
{
|
|
raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
|
|
{
|
|
u64 orun = 1;
|
|
ktime_t delta;
|
|
|
|
delta = ktime_sub(now, hrtimer_get_expires(timer));
|
|
|
|
if (delta.tv64 < 0)
|
|
return 0;
|
|
|
|
if (interval.tv64 < timer->base->resolution.tv64)
|
|
interval.tv64 = timer->base->resolution.tv64;
|
|
|
|
if (unlikely(delta.tv64 >= interval.tv64)) {
|
|
s64 incr = ktime_to_ns(interval);
|
|
|
|
orun = ktime_divns(delta, incr);
|
|
hrtimer_add_expires_ns(timer, incr * orun);
|
|
if (hrtimer_get_expires_tv64(timer) > now.tv64)
|
|
return orun;
|
|
/*
|
|
* This (and the ktime_add() below) is the
|
|
* correction for exact:
|
|
*/
|
|
orun++;
|
|
}
|
|
hrtimer_add_expires(timer, interval);
|
|
|
|
return orun;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_forward);
|
|
|
|
/*
|
|
* enqueue_hrtimer - internal function to (re)start a timer
|
|
*
|
|
* The timer is inserted in expiry order. Insertion into the
|
|
* red black tree is O(log(n)). Must hold the base lock.
|
|
*
|
|
* Returns 1 when the new timer is the leftmost timer in the tree.
|
|
*/
|
|
static int enqueue_hrtimer(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
debug_activate(timer);
|
|
|
|
timerqueue_add(&base->active, &timer->node);
|
|
base->cpu_base->active_bases |= 1 << base->index;
|
|
|
|
/*
|
|
* HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
|
|
* state of a possibly running callback.
|
|
*/
|
|
timer->state |= HRTIMER_STATE_ENQUEUED;
|
|
|
|
return (&timer->node == base->active.next);
|
|
}
|
|
|
|
/*
|
|
* __remove_hrtimer - internal function to remove a timer
|
|
*
|
|
* Caller must hold the base lock.
|
|
*
|
|
* High resolution timer mode reprograms the clock event device when the
|
|
* timer is the one which expires next. The caller can disable this by setting
|
|
* reprogram to zero. This is useful, when the context does a reprogramming
|
|
* anyway (e.g. timer interrupt)
|
|
*/
|
|
static void __remove_hrtimer(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base,
|
|
unsigned long newstate, int reprogram)
|
|
{
|
|
struct timerqueue_node *next_timer;
|
|
if (!(timer->state & HRTIMER_STATE_ENQUEUED))
|
|
goto out;
|
|
|
|
next_timer = timerqueue_getnext(&base->active);
|
|
timerqueue_del(&base->active, &timer->node);
|
|
if (&timer->node == next_timer) {
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
/* Reprogram the clock event device. if enabled */
|
|
if (reprogram && hrtimer_hres_active()) {
|
|
ktime_t expires;
|
|
|
|
expires = ktime_sub(hrtimer_get_expires(timer),
|
|
base->offset);
|
|
if (base->cpu_base->expires_next.tv64 == expires.tv64)
|
|
hrtimer_force_reprogram(base->cpu_base, 1);
|
|
}
|
|
#endif
|
|
}
|
|
if (!timerqueue_getnext(&base->active))
|
|
base->cpu_base->active_bases &= ~(1 << base->index);
|
|
out:
|
|
timer->state = newstate;
|
|
}
|
|
|
|
/*
|
|
* remove hrtimer, called with base lock held
|
|
*/
|
|
static inline int
|
|
remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
|
|
{
|
|
if (hrtimer_is_queued(timer)) {
|
|
unsigned long state;
|
|
int reprogram;
|
|
|
|
/*
|
|
* Remove the timer and force reprogramming when high
|
|
* resolution mode is active and the timer is on the current
|
|
* CPU. If we remove a timer on another CPU, reprogramming is
|
|
* skipped. The interrupt event on this CPU is fired and
|
|
* reprogramming happens in the interrupt handler. This is a
|
|
* rare case and less expensive than a smp call.
|
|
*/
|
|
debug_deactivate(timer);
|
|
timer_stats_hrtimer_clear_start_info(timer);
|
|
reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
|
|
/*
|
|
* We must preserve the CALLBACK state flag here,
|
|
* otherwise we could move the timer base in
|
|
* switch_hrtimer_base.
|
|
*/
|
|
state = timer->state & HRTIMER_STATE_CALLBACK;
|
|
__remove_hrtimer(timer, base, state, reprogram);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
|
|
unsigned long delta_ns, const enum hrtimer_mode mode,
|
|
int wakeup)
|
|
{
|
|
struct hrtimer_clock_base *base, *new_base;
|
|
unsigned long flags;
|
|
int ret, leftmost;
|
|
|
|
base = lock_hrtimer_base(timer, &flags);
|
|
|
|
/* Remove an active timer from the queue: */
|
|
ret = remove_hrtimer(timer, base);
|
|
|
|
/* Switch the timer base, if necessary: */
|
|
new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
|
|
|
|
if (mode & HRTIMER_MODE_REL) {
|
|
tim = ktime_add_safe(tim, new_base->get_time());
|
|
/*
|
|
* CONFIG_TIME_LOW_RES is a temporary way for architectures
|
|
* to signal that they simply return xtime in
|
|
* do_gettimeoffset(). In this case we want to round up by
|
|
* resolution when starting a relative timer, to avoid short
|
|
* timeouts. This will go away with the GTOD framework.
|
|
*/
|
|
#ifdef CONFIG_TIME_LOW_RES
|
|
tim = ktime_add_safe(tim, base->resolution);
|
|
#endif
|
|
}
|
|
|
|
hrtimer_set_expires_range_ns(timer, tim, delta_ns);
|
|
|
|
timer_stats_hrtimer_set_start_info(timer);
|
|
|
|
leftmost = enqueue_hrtimer(timer, new_base);
|
|
|
|
/*
|
|
* Only allow reprogramming if the new base is on this CPU.
|
|
* (it might still be on another CPU if the timer was pending)
|
|
*
|
|
* XXX send_remote_softirq() ?
|
|
*/
|
|
if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases)
|
|
&& hrtimer_enqueue_reprogram(timer, new_base)) {
|
|
if (wakeup) {
|
|
/*
|
|
* We need to drop cpu_base->lock to avoid a
|
|
* lock ordering issue vs. rq->lock.
|
|
*/
|
|
raw_spin_unlock(&new_base->cpu_base->lock);
|
|
raise_softirq_irqoff(HRTIMER_SOFTIRQ);
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
} else {
|
|
__raise_softirq_irqoff(HRTIMER_SOFTIRQ);
|
|
}
|
|
}
|
|
|
|
unlock_hrtimer_base(timer, &flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
|
|
* @timer: the timer to be added
|
|
* @tim: expiry time
|
|
* @delta_ns: "slack" range for the timer
|
|
* @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
|
|
* relative (HRTIMER_MODE_REL)
|
|
*
|
|
* Returns:
|
|
* 0 on success
|
|
* 1 when the timer was active
|
|
*/
|
|
int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
|
|
unsigned long delta_ns, const enum hrtimer_mode mode)
|
|
{
|
|
return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
|
|
|
|
/**
|
|
* hrtimer_start - (re)start an hrtimer on the current CPU
|
|
* @timer: the timer to be added
|
|
* @tim: expiry time
|
|
* @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
|
|
* relative (HRTIMER_MODE_REL)
|
|
*
|
|
* Returns:
|
|
* 0 on success
|
|
* 1 when the timer was active
|
|
*/
|
|
int
|
|
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
|
|
{
|
|
return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_start);
|
|
|
|
|
|
/**
|
|
* hrtimer_try_to_cancel - try to deactivate a timer
|
|
* @timer: hrtimer to stop
|
|
*
|
|
* Returns:
|
|
* 0 when the timer was not active
|
|
* 1 when the timer was active
|
|
* -1 when the timer is currently excuting the callback function and
|
|
* cannot be stopped
|
|
*/
|
|
int hrtimer_try_to_cancel(struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_clock_base *base;
|
|
unsigned long flags;
|
|
int ret = -1;
|
|
|
|
base = lock_hrtimer_base(timer, &flags);
|
|
|
|
if (!hrtimer_callback_running(timer))
|
|
ret = remove_hrtimer(timer, base);
|
|
|
|
unlock_hrtimer_base(timer, &flags);
|
|
|
|
return ret;
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
|
|
|
|
/**
|
|
* hrtimer_cancel - cancel a timer and wait for the handler to finish.
|
|
* @timer: the timer to be cancelled
|
|
*
|
|
* Returns:
|
|
* 0 when the timer was not active
|
|
* 1 when the timer was active
|
|
*/
|
|
int hrtimer_cancel(struct hrtimer *timer)
|
|
{
|
|
for (;;) {
|
|
int ret = hrtimer_try_to_cancel(timer);
|
|
|
|
if (ret >= 0)
|
|
return ret;
|
|
cpu_relax();
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_cancel);
|
|
|
|
/**
|
|
* hrtimer_get_remaining - get remaining time for the timer
|
|
* @timer: the timer to read
|
|
*/
|
|
ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
|
|
{
|
|
unsigned long flags;
|
|
ktime_t rem;
|
|
|
|
lock_hrtimer_base(timer, &flags);
|
|
rem = hrtimer_expires_remaining(timer);
|
|
unlock_hrtimer_base(timer, &flags);
|
|
|
|
return rem;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
|
|
|
|
#ifdef CONFIG_NO_HZ_COMMON
|
|
/**
|
|
* hrtimer_get_next_event - get the time until next expiry event
|
|
*
|
|
* Returns the delta to the next expiry event or KTIME_MAX if no timer
|
|
* is pending.
|
|
*/
|
|
ktime_t hrtimer_get_next_event(void)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
|
|
struct hrtimer_clock_base *base = cpu_base->clock_base;
|
|
ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
|
|
unsigned long flags;
|
|
int i;
|
|
|
|
raw_spin_lock_irqsave(&cpu_base->lock, flags);
|
|
|
|
if (!hrtimer_hres_active()) {
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
|
|
struct hrtimer *timer;
|
|
struct timerqueue_node *next;
|
|
|
|
next = timerqueue_getnext(&base->active);
|
|
if (!next)
|
|
continue;
|
|
|
|
timer = container_of(next, struct hrtimer, node);
|
|
delta.tv64 = hrtimer_get_expires_tv64(timer);
|
|
delta = ktime_sub(delta, base->get_time());
|
|
if (delta.tv64 < mindelta.tv64)
|
|
mindelta.tv64 = delta.tv64;
|
|
}
|
|
}
|
|
|
|
raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
|
|
|
|
if (mindelta.tv64 < 0)
|
|
mindelta.tv64 = 0;
|
|
return mindelta;
|
|
}
|
|
#endif
|
|
|
|
static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
|
|
enum hrtimer_mode mode)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base;
|
|
int base;
|
|
|
|
memset(timer, 0, sizeof(struct hrtimer));
|
|
|
|
cpu_base = &__raw_get_cpu_var(hrtimer_bases);
|
|
|
|
if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
|
|
clock_id = CLOCK_MONOTONIC;
|
|
|
|
base = hrtimer_clockid_to_base(clock_id);
|
|
timer->base = &cpu_base->clock_base[base];
|
|
timerqueue_init(&timer->node);
|
|
|
|
#ifdef CONFIG_TIMER_STATS
|
|
timer->start_site = NULL;
|
|
timer->start_pid = -1;
|
|
memset(timer->start_comm, 0, TASK_COMM_LEN);
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* hrtimer_init - initialize a timer to the given clock
|
|
* @timer: the timer to be initialized
|
|
* @clock_id: the clock to be used
|
|
* @mode: timer mode abs/rel
|
|
*/
|
|
void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
|
|
enum hrtimer_mode mode)
|
|
{
|
|
debug_init(timer, clock_id, mode);
|
|
__hrtimer_init(timer, clock_id, mode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_init);
|
|
|
|
/**
|
|
* hrtimer_get_res - get the timer resolution for a clock
|
|
* @which_clock: which clock to query
|
|
* @tp: pointer to timespec variable to store the resolution
|
|
*
|
|
* Store the resolution of the clock selected by @which_clock in the
|
|
* variable pointed to by @tp.
|
|
*/
|
|
int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base;
|
|
int base = hrtimer_clockid_to_base(which_clock);
|
|
|
|
cpu_base = &__raw_get_cpu_var(hrtimer_bases);
|
|
*tp = ktime_to_timespec(cpu_base->clock_base[base].resolution);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_get_res);
|
|
|
|
static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
|
|
{
|
|
struct hrtimer_clock_base *base = timer->base;
|
|
struct hrtimer_cpu_base *cpu_base = base->cpu_base;
|
|
enum hrtimer_restart (*fn)(struct hrtimer *);
|
|
int restart;
|
|
|
|
WARN_ON(!irqs_disabled());
|
|
|
|
debug_deactivate(timer);
|
|
__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
|
|
timer_stats_account_hrtimer(timer);
|
|
fn = timer->function;
|
|
|
|
/*
|
|
* Because we run timers from hardirq context, there is no chance
|
|
* they get migrated to another cpu, therefore its safe to unlock
|
|
* the timer base.
|
|
*/
|
|
raw_spin_unlock(&cpu_base->lock);
|
|
trace_hrtimer_expire_entry(timer, now);
|
|
restart = fn(timer);
|
|
trace_hrtimer_expire_exit(timer);
|
|
raw_spin_lock(&cpu_base->lock);
|
|
|
|
/*
|
|
* Note: We clear the CALLBACK bit after enqueue_hrtimer and
|
|
* we do not reprogramm the event hardware. Happens either in
|
|
* hrtimer_start_range_ns() or in hrtimer_interrupt()
|
|
*/
|
|
if (restart != HRTIMER_NORESTART) {
|
|
BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
|
|
enqueue_hrtimer(timer, base);
|
|
}
|
|
|
|
WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));
|
|
|
|
timer->state &= ~HRTIMER_STATE_CALLBACK;
|
|
}
|
|
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
|
|
/*
|
|
* High resolution timer interrupt
|
|
* Called with interrupts disabled
|
|
*/
|
|
void hrtimer_interrupt(struct clock_event_device *dev)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
|
|
ktime_t expires_next, now, entry_time, delta;
|
|
int i, retries = 0;
|
|
|
|
BUG_ON(!cpu_base->hres_active);
|
|
cpu_base->nr_events++;
|
|
dev->next_event.tv64 = KTIME_MAX;
|
|
|
|
raw_spin_lock(&cpu_base->lock);
|
|
entry_time = now = hrtimer_update_base(cpu_base);
|
|
retry:
|
|
expires_next.tv64 = KTIME_MAX;
|
|
/*
|
|
* We set expires_next to KTIME_MAX here with cpu_base->lock
|
|
* held to prevent that a timer is enqueued in our queue via
|
|
* the migration code. This does not affect enqueueing of
|
|
* timers which run their callback and need to be requeued on
|
|
* this CPU.
|
|
*/
|
|
cpu_base->expires_next.tv64 = KTIME_MAX;
|
|
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
|
|
struct hrtimer_clock_base *base;
|
|
struct timerqueue_node *node;
|
|
ktime_t basenow;
|
|
|
|
if (!(cpu_base->active_bases & (1 << i)))
|
|
continue;
|
|
|
|
base = cpu_base->clock_base + i;
|
|
basenow = ktime_add(now, base->offset);
|
|
|
|
while ((node = timerqueue_getnext(&base->active))) {
|
|
struct hrtimer *timer;
|
|
|
|
timer = container_of(node, struct hrtimer, node);
|
|
|
|
/*
|
|
* The immediate goal for using the softexpires is
|
|
* minimizing wakeups, not running timers at the
|
|
* earliest interrupt after their soft expiration.
|
|
* This allows us to avoid using a Priority Search
|
|
* Tree, which can answer a stabbing querry for
|
|
* overlapping intervals and instead use the simple
|
|
* BST we already have.
|
|
* We don't add extra wakeups by delaying timers that
|
|
* are right-of a not yet expired timer, because that
|
|
* timer will have to trigger a wakeup anyway.
|
|
*/
|
|
|
|
if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
|
|
ktime_t expires;
|
|
|
|
expires = ktime_sub(hrtimer_get_expires(timer),
|
|
base->offset);
|
|
if (expires.tv64 < 0)
|
|
expires.tv64 = KTIME_MAX;
|
|
if (expires.tv64 < expires_next.tv64)
|
|
expires_next = expires;
|
|
break;
|
|
}
|
|
|
|
__run_hrtimer(timer, &basenow);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Store the new expiry value so the migration code can verify
|
|
* against it.
|
|
*/
|
|
cpu_base->expires_next = expires_next;
|
|
raw_spin_unlock(&cpu_base->lock);
|
|
|
|
/* Reprogramming necessary ? */
|
|
if (expires_next.tv64 == KTIME_MAX ||
|
|
!tick_program_event(expires_next, 0)) {
|
|
cpu_base->hang_detected = 0;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* The next timer was already expired due to:
|
|
* - tracing
|
|
* - long lasting callbacks
|
|
* - being scheduled away when running in a VM
|
|
*
|
|
* We need to prevent that we loop forever in the hrtimer
|
|
* interrupt routine. We give it 3 attempts to avoid
|
|
* overreacting on some spurious event.
|
|
*
|
|
* Acquire base lock for updating the offsets and retrieving
|
|
* the current time.
|
|
*/
|
|
raw_spin_lock(&cpu_base->lock);
|
|
now = hrtimer_update_base(cpu_base);
|
|
cpu_base->nr_retries++;
|
|
if (++retries < 3)
|
|
goto retry;
|
|
/*
|
|
* Give the system a chance to do something else than looping
|
|
* here. We stored the entry time, so we know exactly how long
|
|
* we spent here. We schedule the next event this amount of
|
|
* time away.
|
|
*/
|
|
cpu_base->nr_hangs++;
|
|
cpu_base->hang_detected = 1;
|
|
raw_spin_unlock(&cpu_base->lock);
|
|
delta = ktime_sub(now, entry_time);
|
|
if (delta.tv64 > cpu_base->max_hang_time.tv64)
|
|
cpu_base->max_hang_time = delta;
|
|
/*
|
|
* Limit it to a sensible value as we enforce a longer
|
|
* delay. Give the CPU at least 100ms to catch up.
|
|
*/
|
|
if (delta.tv64 > 100 * NSEC_PER_MSEC)
|
|
expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
|
|
else
|
|
expires_next = ktime_add(now, delta);
|
|
tick_program_event(expires_next, 1);
|
|
printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
|
|
ktime_to_ns(delta));
|
|
}
|
|
|
|
/*
|
|
* local version of hrtimer_peek_ahead_timers() called with interrupts
|
|
* disabled.
|
|
*/
|
|
static void __hrtimer_peek_ahead_timers(void)
|
|
{
|
|
struct tick_device *td;
|
|
|
|
if (!hrtimer_hres_active())
|
|
return;
|
|
|
|
td = &__get_cpu_var(tick_cpu_device);
|
|
if (td && td->evtdev)
|
|
hrtimer_interrupt(td->evtdev);
|
|
}
|
|
|
|
/**
|
|
* hrtimer_peek_ahead_timers -- run soft-expired timers now
|
|
*
|
|
* hrtimer_peek_ahead_timers will peek at the timer queue of
|
|
* the current cpu and check if there are any timers for which
|
|
* the soft expires time has passed. If any such timers exist,
|
|
* they are run immediately and then removed from the timer queue.
|
|
*
|
|
*/
|
|
void hrtimer_peek_ahead_timers(void)
|
|
{
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
__hrtimer_peek_ahead_timers();
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static void run_hrtimer_softirq(struct softirq_action *h)
|
|
{
|
|
hrtimer_peek_ahead_timers();
|
|
}
|
|
|
|
#else /* CONFIG_HIGH_RES_TIMERS */
|
|
|
|
static inline void __hrtimer_peek_ahead_timers(void) { }
|
|
|
|
#endif /* !CONFIG_HIGH_RES_TIMERS */
|
|
|
|
/*
|
|
* Called from timer softirq every jiffy, expire hrtimers:
|
|
*
|
|
* For HRT its the fall back code to run the softirq in the timer
|
|
* softirq context in case the hrtimer initialization failed or has
|
|
* not been done yet.
|
|
*/
|
|
void hrtimer_run_pending(void)
|
|
{
|
|
if (hrtimer_hres_active())
|
|
return;
|
|
|
|
/*
|
|
* This _is_ ugly: We have to check in the softirq context,
|
|
* whether we can switch to highres and / or nohz mode. The
|
|
* clocksource switch happens in the timer interrupt with
|
|
* xtime_lock held. Notification from there only sets the
|
|
* check bit in the tick_oneshot code, otherwise we might
|
|
* deadlock vs. xtime_lock.
|
|
*/
|
|
if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
|
|
hrtimer_switch_to_hres();
|
|
}
|
|
|
|
/*
|
|
* Called from hardirq context every jiffy
|
|
*/
|
|
void hrtimer_run_queues(void)
|
|
{
|
|
struct timerqueue_node *node;
|
|
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
|
|
struct hrtimer_clock_base *base;
|
|
int index, gettime = 1;
|
|
|
|
if (hrtimer_hres_active())
|
|
return;
|
|
|
|
for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
|
|
base = &cpu_base->clock_base[index];
|
|
if (!timerqueue_getnext(&base->active))
|
|
continue;
|
|
|
|
if (gettime) {
|
|
hrtimer_get_softirq_time(cpu_base);
|
|
gettime = 0;
|
|
}
|
|
|
|
raw_spin_lock(&cpu_base->lock);
|
|
|
|
while ((node = timerqueue_getnext(&base->active))) {
|
|
struct hrtimer *timer;
|
|
|
|
timer = container_of(node, struct hrtimer, node);
|
|
if (base->softirq_time.tv64 <=
|
|
hrtimer_get_expires_tv64(timer))
|
|
break;
|
|
|
|
__run_hrtimer(timer, &base->softirq_time);
|
|
}
|
|
raw_spin_unlock(&cpu_base->lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Sleep related functions:
|
|
*/
|
|
static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_sleeper *t =
|
|
container_of(timer, struct hrtimer_sleeper, timer);
|
|
struct task_struct *task = t->task;
|
|
|
|
t->task = NULL;
|
|
if (task)
|
|
wake_up_process(task);
|
|
|
|
return HRTIMER_NORESTART;
|
|
}
|
|
|
|
void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
|
|
{
|
|
sl->timer.function = hrtimer_wakeup;
|
|
sl->task = task;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
|
|
|
|
static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
|
|
{
|
|
hrtimer_init_sleeper(t, current);
|
|
|
|
do {
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
hrtimer_start_expires(&t->timer, mode);
|
|
if (!hrtimer_active(&t->timer))
|
|
t->task = NULL;
|
|
|
|
if (likely(t->task))
|
|
freezable_schedule();
|
|
|
|
hrtimer_cancel(&t->timer);
|
|
mode = HRTIMER_MODE_ABS;
|
|
|
|
} while (t->task && !signal_pending(current));
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
return t->task == NULL;
|
|
}
|
|
|
|
static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
|
|
{
|
|
struct timespec rmt;
|
|
ktime_t rem;
|
|
|
|
rem = hrtimer_expires_remaining(timer);
|
|
if (rem.tv64 <= 0)
|
|
return 0;
|
|
rmt = ktime_to_timespec(rem);
|
|
|
|
if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
|
|
return -EFAULT;
|
|
|
|
return 1;
|
|
}
|
|
|
|
long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
|
|
{
|
|
struct hrtimer_sleeper t;
|
|
struct timespec __user *rmtp;
|
|
int ret = 0;
|
|
|
|
hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,
|
|
HRTIMER_MODE_ABS);
|
|
hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
|
|
|
|
if (do_nanosleep(&t, HRTIMER_MODE_ABS))
|
|
goto out;
|
|
|
|
rmtp = restart->nanosleep.rmtp;
|
|
if (rmtp) {
|
|
ret = update_rmtp(&t.timer, rmtp);
|
|
if (ret <= 0)
|
|
goto out;
|
|
}
|
|
|
|
/* The other values in restart are already filled in */
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
out:
|
|
destroy_hrtimer_on_stack(&t.timer);
|
|
return ret;
|
|
}
|
|
|
|
long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
|
|
const enum hrtimer_mode mode, const clockid_t clockid)
|
|
{
|
|
struct restart_block *restart;
|
|
struct hrtimer_sleeper t;
|
|
int ret = 0;
|
|
unsigned long slack;
|
|
|
|
slack = current->timer_slack_ns;
|
|
if (dl_task(current) || rt_task(current))
|
|
slack = 0;
|
|
|
|
hrtimer_init_on_stack(&t.timer, clockid, mode);
|
|
hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
|
|
if (do_nanosleep(&t, mode))
|
|
goto out;
|
|
|
|
/* Absolute timers do not update the rmtp value and restart: */
|
|
if (mode == HRTIMER_MODE_ABS) {
|
|
ret = -ERESTARTNOHAND;
|
|
goto out;
|
|
}
|
|
|
|
if (rmtp) {
|
|
ret = update_rmtp(&t.timer, rmtp);
|
|
if (ret <= 0)
|
|
goto out;
|
|
}
|
|
|
|
restart = ¤t_thread_info()->restart_block;
|
|
restart->fn = hrtimer_nanosleep_restart;
|
|
restart->nanosleep.clockid = t.timer.base->clockid;
|
|
restart->nanosleep.rmtp = rmtp;
|
|
restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
|
|
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
out:
|
|
destroy_hrtimer_on_stack(&t.timer);
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
|
|
struct timespec __user *, rmtp)
|
|
{
|
|
struct timespec tu;
|
|
|
|
if (copy_from_user(&tu, rqtp, sizeof(tu)))
|
|
return -EFAULT;
|
|
|
|
if (!timespec_valid(&tu))
|
|
return -EINVAL;
|
|
|
|
return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
|
|
}
|
|
|
|
/*
|
|
* Functions related to boot-time initialization:
|
|
*/
|
|
static void init_hrtimers_cpu(int cpu)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
|
|
int i;
|
|
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
|
|
cpu_base->clock_base[i].cpu_base = cpu_base;
|
|
timerqueue_init_head(&cpu_base->clock_base[i].active);
|
|
}
|
|
|
|
hrtimer_init_hres(cpu_base);
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
|
|
struct hrtimer_clock_base *new_base)
|
|
{
|
|
struct hrtimer *timer;
|
|
struct timerqueue_node *node;
|
|
|
|
while ((node = timerqueue_getnext(&old_base->active))) {
|
|
timer = container_of(node, struct hrtimer, node);
|
|
BUG_ON(hrtimer_callback_running(timer));
|
|
debug_deactivate(timer);
|
|
|
|
/*
|
|
* Mark it as STATE_MIGRATE not INACTIVE otherwise the
|
|
* timer could be seen as !active and just vanish away
|
|
* under us on another CPU
|
|
*/
|
|
__remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
|
|
timer->base = new_base;
|
|
/*
|
|
* Enqueue the timers on the new cpu. This does not
|
|
* reprogram the event device in case the timer
|
|
* expires before the earliest on this CPU, but we run
|
|
* hrtimer_interrupt after we migrated everything to
|
|
* sort out already expired timers and reprogram the
|
|
* event device.
|
|
*/
|
|
enqueue_hrtimer(timer, new_base);
|
|
|
|
/* Clear the migration state bit */
|
|
timer->state &= ~HRTIMER_STATE_MIGRATE;
|
|
}
|
|
}
|
|
|
|
static void migrate_hrtimers(int scpu)
|
|
{
|
|
struct hrtimer_cpu_base *old_base, *new_base;
|
|
int i;
|
|
|
|
BUG_ON(cpu_online(scpu));
|
|
tick_cancel_sched_timer(scpu);
|
|
|
|
local_irq_disable();
|
|
old_base = &per_cpu(hrtimer_bases, scpu);
|
|
new_base = &__get_cpu_var(hrtimer_bases);
|
|
/*
|
|
* The caller is globally serialized and nobody else
|
|
* takes two locks at once, deadlock is not possible.
|
|
*/
|
|
raw_spin_lock(&new_base->lock);
|
|
raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
|
|
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
|
|
migrate_hrtimer_list(&old_base->clock_base[i],
|
|
&new_base->clock_base[i]);
|
|
}
|
|
|
|
raw_spin_unlock(&old_base->lock);
|
|
raw_spin_unlock(&new_base->lock);
|
|
|
|
/* Check, if we got expired work to do */
|
|
__hrtimer_peek_ahead_timers();
|
|
local_irq_enable();
|
|
}
|
|
|
|
#endif /* CONFIG_HOTPLUG_CPU */
|
|
|
|
static int hrtimer_cpu_notify(struct notifier_block *self,
|
|
unsigned long action, void *hcpu)
|
|
{
|
|
int scpu = (long)hcpu;
|
|
|
|
switch (action) {
|
|
|
|
case CPU_UP_PREPARE:
|
|
case CPU_UP_PREPARE_FROZEN:
|
|
init_hrtimers_cpu(scpu);
|
|
break;
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
case CPU_DYING:
|
|
case CPU_DYING_FROZEN:
|
|
clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
|
|
break;
|
|
case CPU_DEAD:
|
|
case CPU_DEAD_FROZEN:
|
|
{
|
|
clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
|
|
migrate_hrtimers(scpu);
|
|
break;
|
|
}
|
|
#endif
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block hrtimers_nb = {
|
|
.notifier_call = hrtimer_cpu_notify,
|
|
};
|
|
|
|
void __init hrtimers_init(void)
|
|
{
|
|
hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
|
|
(void *)(long)smp_processor_id());
|
|
register_cpu_notifier(&hrtimers_nb);
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* schedule_hrtimeout_range_clock - sleep until timeout
|
|
* @expires: timeout value (ktime_t)
|
|
* @delta: slack in expires timeout (ktime_t)
|
|
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
|
|
* @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
|
|
*/
|
|
int __sched
|
|
schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
|
|
const enum hrtimer_mode mode, int clock)
|
|
{
|
|
struct hrtimer_sleeper t;
|
|
|
|
/*
|
|
* Optimize when a zero timeout value is given. It does not
|
|
* matter whether this is an absolute or a relative time.
|
|
*/
|
|
if (expires && !expires->tv64) {
|
|
__set_current_state(TASK_RUNNING);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* A NULL parameter means "infinite"
|
|
*/
|
|
if (!expires) {
|
|
schedule();
|
|
__set_current_state(TASK_RUNNING);
|
|
return -EINTR;
|
|
}
|
|
|
|
hrtimer_init_on_stack(&t.timer, clock, mode);
|
|
hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
|
|
|
|
hrtimer_init_sleeper(&t, current);
|
|
|
|
hrtimer_start_expires(&t.timer, mode);
|
|
if (!hrtimer_active(&t.timer))
|
|
t.task = NULL;
|
|
|
|
if (likely(t.task))
|
|
schedule();
|
|
|
|
hrtimer_cancel(&t.timer);
|
|
destroy_hrtimer_on_stack(&t.timer);
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
return !t.task ? 0 : -EINTR;
|
|
}
|
|
|
|
/**
|
|
* schedule_hrtimeout_range - sleep until timeout
|
|
* @expires: timeout value (ktime_t)
|
|
* @delta: slack in expires timeout (ktime_t)
|
|
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
|
|
*
|
|
* Make the current task sleep until the given expiry time has
|
|
* elapsed. The routine will return immediately unless
|
|
* the current task state has been set (see set_current_state()).
|
|
*
|
|
* The @delta argument gives the kernel the freedom to schedule the
|
|
* actual wakeup to a time that is both power and performance friendly.
|
|
* The kernel give the normal best effort behavior for "@expires+@delta",
|
|
* but may decide to fire the timer earlier, but no earlier than @expires.
|
|
*
|
|
* You can set the task state as follows -
|
|
*
|
|
* %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
|
|
* pass before the routine returns.
|
|
*
|
|
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
|
|
* delivered to the current task.
|
|
*
|
|
* The current task state is guaranteed to be TASK_RUNNING when this
|
|
* routine returns.
|
|
*
|
|
* Returns 0 when the timer has expired otherwise -EINTR
|
|
*/
|
|
int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
|
|
const enum hrtimer_mode mode)
|
|
{
|
|
return schedule_hrtimeout_range_clock(expires, delta, mode,
|
|
CLOCK_MONOTONIC);
|
|
}
|
|
EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
|
|
|
|
/**
|
|
* schedule_hrtimeout - sleep until timeout
|
|
* @expires: timeout value (ktime_t)
|
|
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
|
|
*
|
|
* Make the current task sleep until the given expiry time has
|
|
* 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 time is guaranteed to
|
|
* pass before the routine returns.
|
|
*
|
|
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
|
|
* delivered to the current task.
|
|
*
|
|
* The current task state is guaranteed to be TASK_RUNNING when this
|
|
* routine returns.
|
|
*
|
|
* Returns 0 when the timer has expired otherwise -EINTR
|
|
*/
|
|
int __sched schedule_hrtimeout(ktime_t *expires,
|
|
const enum hrtimer_mode mode)
|
|
{
|
|
return schedule_hrtimeout_range(expires, 0, mode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(schedule_hrtimeout);
|