Messages in this thread | | | Date | Wed, 3 Jun 2009 12:36:03 +0900 | From | Paul Mundt <> | Subject | Re: [PATCH] sched: sched_clock() clocksource handling. |
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On Tue, Jun 02, 2009 at 04:49:26AM -0700, Daniel Walker wrote: > On Tue, 2009-06-02 at 16:54 +0900, Paul Mundt wrote: > > unsigned long long __attribute__((weak)) sched_clock(void) > > { > > - return (unsigned long long)(jiffies - INITIAL_JIFFIES) > > - * (NSEC_PER_SEC / HZ); > > + unsigned long long time; > > + struct clocksource *clock; > > + > > + rcu_read_lock(); > > + clock = rcu_dereference(sched_clocksource); > > + time = cyc2ns(clock, clocksource_read(clock)); > > + rcu_read_unlock(); > > + > > + return time; > > } > > My concerns with the locking here still stand. Nothing you've said or > done bolsters the clocksource in modules argument. I think what your > planning for sh clocksources seems very inelegant. I would imagine a > better solution is out there. I'd prefer if you just leave sched_clock > alone. > This is the first I've heard you mention locking concerns, and as usual there is not enough technical content (or any, really) to go on to even reply to this. Whether you consider my solution for sh clocksources elegant or not is irrelevant, as I wasn't soliciting feedback, and it's a problem that has to be dealt with regardless of whether it's a pretty one or not.
If at such a time you wish to post something bordering on a real technical concern, we can continue this thread of conversation, until then I'll be sure to drop you from future versions of the patch. If you want to hand-wave, do it somewhere else, thanks.
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