hrtimer: Get rid of the resolution field in hrtimer_clock_base
authorThomas Gleixner <tglx@linutronix.de>
Tue, 14 Apr 2015 21:08:27 +0000 (21:08 +0000)
committerThomas Gleixner <tglx@linutronix.de>
Wed, 22 Apr 2015 15:06:48 +0000 (17:06 +0200)
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>
include/linux/hrtimer.h
kernel/time/hrtimer.c
kernel/time/timer_list.c

index 7770676c387a66cec9a8a3d8333bfa6e1e56ffe8..bc6f91b5443badd775d8b25b8389b45f9f09abe6 100644 (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) { }
 
 /*
index 9abd50b60e83e6457d2686aaf1178c53d8da29cc..965687a1fce60086935e79af41a5d7d20080c0e7 100644 (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);
index 5960af2196acca6839c1271293e4c6186695b208..bdd5e987f1154319512eb6506049726a33aa905f 100644 (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");