| Date | Tue, 26 Sep 2017 14:52:06 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 18/25] hrtimer: Enable soft and hard hrtimer |
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On Thu, Aug 31, 2017 at 12:23:42PM -0000, Anna-Maria Gleixner wrote: > --- a/include/linux/hrtimer.h > +++ b/include/linux/hrtimer.h > @@ -23,6 +23,17 @@ > #include <linux/timer.h> > #include <linux/timerqueue.h> > > +/* > + * Clock ids for hrtimers which expire in softirq context. These clock ids > + * are kernel internal and never exported to user space. > + */ > +#define HRTIMER_BASE_SOFT_MASK MAX_CLOCKS > + > +#define CLOCK_REALTIME_SOFT (CLOCK_REALTIME | HRTIMER_BASE_SOFT_MASK) > +#define CLOCK_MONOTONIC_SOFT (CLOCK_MONOTONIC | HRTIMER_BASE_SOFT_MASK) > +#define CLOCK_BOOTTIME_SOFT (CLOCK_BOOTTIME | HRTIMER_BASE_SOFT_MASK) > +#define CLOCK_TAI_SOFT (CLOCK_TAI | HRTIMER_BASE_SOFT_MASK) > + > struct hrtimer_clock_base; > struct hrtimer_cpu_base; >
> --- a/kernel/time/hrtimer.c > +++ b/kernel/time/hrtimer.c > @@ -1173,7 +1161,7 @@ u64 hrtimer_get_next_event(void) > > static inline int hrtimer_clockid_to_base(clockid_t clock_id) > { > + if (likely(clock_id < MAX_CLOCKS_HRT)) { > int base = hrtimer_clock_to_base_table[clock_id]; > > if (likely(base != HRTIMER_MAX_CLOCK_BASES)) > @@ -1193,8 +1181,12 @@ static void __hrtimer_init(struct hrtime > > cpu_base = raw_cpu_ptr(&hrtimer_bases); > > + if (mode != HRTIMER_MODE_ABS) { > + if (clock_id == CLOCK_REALTIME) > + clock_id = CLOCK_MONOTONIC; > + else if (clock_id == CLOCK_REALTIME_SOFT) > + clock_id = CLOCK_MONOTONIC_SOFT; > + } > > base = hrtimer_clockid_to_base(clock_id); > timer->base = &cpu_base->clock_base[base];
So why expose these extra bases at all, why not stick another flag in MODE? These extra bases is a pure implementation detail imo; you could equally implement the functionality without (albeit at extra cost).
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