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hrtimer: Get rid of the resolution field in hrtimer_clock_base

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The field has no value because all clock bases have the same
resolution. The resolution only changes when we switch to high
resolution timer mode. We can evaluate that from a single static
variable as well. In the !HIGHRES case its simply a constant.

Export the variable, so we can simplify the usage sites.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20150414203500.645454122@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2015-04-14 21:08:27 +00:00
parent d9f0acdeef
commit 398ca17fb5
3 changed files with 17 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/hrtimer.h
View File

@ -137,7 +137,6 @@ struct hrtimer_sleeper {
* timer to a base on another cpu.
* @clockid: clock id for per_cpu support
* @active: red black tree root node for the active timers
* @resolution: the resolution of the clock, in nanoseconds
* @get_time: function to retrieve the current time of the clock
* @softirq_time: the time when running the hrtimer queue in the softirq
* @offset: offset of this clock to the monotonic base
@ -147,7 +146,6 @@ struct hrtimer_clock_base {
int index;
clockid_t clockid;
struct timerqueue_head active;
ktime_t resolution;
ktime_t (*get_time)(void);
ktime_t softirq_time;
ktime_t offset;
@ -295,11 +293,15 @@ extern void hrtimer_peek_ahead_timers(void);
extern void clock_was_set_delayed(void);
extern unsigned int hrtimer_resolution;
#else
# define MONOTONIC_RES_NSEC LOW_RES_NSEC
# define KTIME_MONOTONIC_RES KTIME_LOW_RES
#define hrtimer_resolution LOW_RES_NSEC
static inline void hrtimer_peek_ahead_timers(void) { }
/*

26
kernel/time/hrtimer.c
View File

@ -66,7 +66,6 @@
*/
DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
{
.lock = __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases.lock),
.clock_base =
{
@ -74,25 +73,21 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
.index = HRTIMER_BASE_MONOTONIC,
.clockid = CLOCK_MONOTONIC,
.get_time = &ktime_get,
.resolution = KTIME_LOW_RES,
},
{
.index = HRTIMER_BASE_REALTIME,
.clockid = CLOCK_REALTIME,
.get_time = &ktime_get_real,
.resolution = KTIME_LOW_RES,
},
{
.index = HRTIMER_BASE_BOOTTIME,
.clockid = CLOCK_BOOTTIME,
.get_time = &ktime_get_boottime,
.resolution = KTIME_LOW_RES,
},
{
.index = HRTIMER_BASE_TAI,
.clockid = CLOCK_TAI,
.get_time = &ktime_get_clocktai,
.resolution = KTIME_LOW_RES,
},
}
};
@ -478,6 +473,8 @@ static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
* High resolution timer enabled ?
*/
static int hrtimer_hres_enabled __read_mostly = 1;
unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;
EXPORT_SYMBOL_GPL(hrtimer_resolution);
/*
* Enable / Disable high resolution mode
@ -660,7 +657,7 @@ static void retrigger_next_event(void *arg)
*/
static int hrtimer_switch_to_hres(void)
{
int i, cpu = smp_processor_id();
int cpu = smp_processor_id();
struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
unsigned long flags;
@ -676,8 +673,7 @@ static int hrtimer_switch_to_hres(void)
return 0;
}
base->hres_active = 1;
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
base->clock_base[i].resolution = KTIME_HIGH_RES;
hrtimer_resolution = HIGH_RES_NSEC;
tick_setup_sched_timer();
/* "Retrigger" the interrupt to get things going */
@ -820,8 +816,8 @@ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
if (delta.tv64 < 0)
return 0;
if (interval.tv64 < timer->base->resolution.tv64)
interval.tv64 = timer->base->resolution.tv64;
if (interval.tv64 < hrtimer_resolution)
interval.tv64 = hrtimer_resolution;
if (unlikely(delta.tv64 >= interval.tv64)) {
s64 incr = ktime_to_ns(interval);
@ -963,7 +959,7 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
* timeouts. This will go away with the GTOD framework.
*/
#ifdef CONFIG_TIME_LOW_RES
tim = ktime_add_safe(tim, base->resolution);
tim = ktime_add_safe(tim, ktime_set(0, hrtimer_resolution));
#endif
}
@ -1193,12 +1189,8 @@ EXPORT_SYMBOL_GPL(hrtimer_init);
*/
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_cpu_ptr(&hrtimer_bases);
*tp = ktime_to_timespec(cpu_base->clock_base[base].resolution);
tp->tv_sec = 0;
tp->tv_nsec = hrtimer_resolution;
return 0;
}
EXPORT_SYMBOL_GPL(hrtimer_get_res);

8
kernel/time/timer_list.c
View File

@ -127,10 +127,10 @@ static void
print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
{
SEQ_printf(m, " .base: %pK\n", base);
SEQ_printf(m, " .index: %d\n",
base->index);
SEQ_printf(m, " .resolution: %Lu nsecs\n",
(unsigned long long)ktime_to_ns(base->resolution));
SEQ_printf(m, " .index: %d\n", base->index);
SEQ_printf(m, " .resolution: %u nsecs\n", (unsigned) hrtimer_resolution);
SEQ_printf(m, " .get_time: ");
print_name_offset(m, base->get_time);
SEQ_printf(m, "\n");