dlan17/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

timerfd: Manage cancelable timers in timerfd

Browse Source 
Peter is concerned about the extra scan of CLOCK_REALTIME_COS in the
timer interrupt. Yes, I did not think about it, because the solution
was so elegant. I didn't like the extra list in timerfd when it was
proposed some time ago, but with a rcu based list the list walk it's
less horrible than the original global lock, which was held over the
list iteration.

Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
This commit is contained in:
Thomas Gleixner
2011-05-20 16:18:50 +02:00
parent 250f972d85
commit 9ec2690758
5 changed files with 117 additions and 106 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/hrtimer.c
+32 -62
View File
@@ -78,11 +78,6 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
.get_time = &ktime_get_boottime,
.resolution = KTIME_LOW_RES,
},
{
.index = CLOCK_REALTIME_COS,
.get_time = &ktime_get_real,
.resolution = KTIME_LOW_RES,
},
}
};
@@ -90,7 +85,6 @@ static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
[CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
[CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
[CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
[CLOCK_REALTIME_COS] = HRTIMER_BASE_REALTIME_COS,
};
static inline int hrtimer_clockid_to_base(clockid_t clock_id)
@@ -116,7 +110,6 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
base->clock_base[HRTIMER_BASE_REALTIME_COS].softirq_time = xtim;
}
/*
@@ -486,8 +479,6 @@ static inline void debug_deactivate(struct hrtimer *timer)
trace_hrtimer_cancel(timer);
}
static void hrtimer_expire_cancelable(struct hrtimer_cpu_base *cpu_base);
/* High resolution timer related functions */
#ifdef CONFIG_HIGH_RES_TIMERS
@@ -663,7 +654,33 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
return 0;
}
static void retrigger_next_event(void *arg);
/*
* 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);
struct timespec realtime_offset, xtim, wtm, sleep;
if (!hrtimer_hres_active())
return;
/* Optimized out for !HIGH_RES */
get_xtime_and_monotonic_and_sleep_offset(&xtim, &wtm, &sleep);
set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
/* Adjust CLOCK_REALTIME offset */
raw_spin_lock(&base->lock);
base->clock_base[HRTIMER_BASE_REALTIME].offset =
timespec_to_ktime(realtime_offset);
base->clock_base[HRTIMER_BASE_BOOTTIME].offset =
timespec_to_ktime(sleep);
hrtimer_force_reprogram(base, 0);
raw_spin_unlock(&base->lock);
}
/*
* Switch to high resolution mode
@@ -711,45 +728,10 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
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 */
/*
* 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);
struct timespec realtime_offset, xtim, wtm, sleep;
if (!hrtimer_hres_active()) {
raw_spin_lock(&base->lock);
hrtimer_expire_cancelable(base);
raw_spin_unlock(&base->lock);
return;
}
/* Optimized out for !HIGH_RES */
get_xtime_and_monotonic_and_sleep_offset(&xtim, &wtm, &sleep);
set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
/* Adjust CLOCK_REALTIME offset */
raw_spin_lock(&base->lock);
base->clock_base[HRTIMER_BASE_REALTIME].offset =
timespec_to_ktime(realtime_offset);
base->clock_base[HRTIMER_BASE_BOOTTIME].offset =
timespec_to_ktime(sleep);
base->clock_base[HRTIMER_BASE_REALTIME_COS].offset =
timespec_to_ktime(realtime_offset);
hrtimer_expire_cancelable(base);
hrtimer_force_reprogram(base, 0);
raw_spin_unlock(&base->lock);
}
/*
* Clock realtime was set
*
@@ -763,8 +745,11 @@ static void retrigger_next_event(void *arg)
*/
void clock_was_set(void)
{
#ifdef CONFIG_HIGHRES_TIMERS
/* Retrigger the CPU local events everywhere */
on_each_cpu(retrigger_next_event, NULL, 1);
#endif
timerfd_clock_was_set();
}
/*
@@ -777,6 +762,7 @@ void hrtimers_resume(void)
KERN_INFO "hrtimers_resume() called with IRQs enabled!");
retrigger_next_event(NULL);
timerfd_clock_was_set();
}
static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
@@ -1240,22 +1226,6 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
timer->state &= ~HRTIMER_STATE_CALLBACK;
}
static void hrtimer_expire_cancelable(struct hrtimer_cpu_base *cpu_base)
{
struct timerqueue_node *node;
struct hrtimer_clock_base *base;
ktime_t now = ktime_get_real();
base = &cpu_base->clock_base[HRTIMER_BASE_REALTIME_COS];
while ((node = timerqueue_getnext(&base->active))) {
struct hrtimer *timer;
timer = container_of(node, struct hrtimer, node);
__run_hrtimer(timer, &now);
}
}
#ifdef CONFIG_HIGH_RES_TIMERS
/*