Messages in this thread |  | | Date | Wed, 27 Sep 2017 17:54:02 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH 18/25] hrtimer: Enable soft and hard hrtimer |
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On Wed, 27 Sep 2017, Anna-Maria Gleixner wrote: > On Tue, 26 Sep 2017, Peter Zijlstra wrote: > > > 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).
Right and that cost too high.
> > > > It was Thomas' request not to use a flag for this.
We can make that a flag as well. There is no hard requirement for making it a CLOCK. Peter is right that it's a pure internal implementation detail and we can hide it from the outside world.
Thanks,
tglx
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