On Tue, 2 Jun 2015, Carsten Emde wrote: > > > static void __iomem *tcaddr; > > > +static cycle_t (*do_sched_clock_get_cycles)(struct clocksource *cs); > > > > what's that for? Indirection for indirection sake? > The code apparently provides two different functions to read the current clock > - depending on whether the clock is setup in single-channel mode or not. > > The default function is predefined in the struct clocksource clksrc: > .read = tc_get_cycles > This structure element may later on be overwritten, if the counter is > configured in single-channel mode: > clksrc.read = tc_get_cycles32; > > This is why my code sets do_sched_clock_get_cycles to clksrc.read before > sched_clock is registered to make sure the appropriate read function will be > used. return clksrc.read(NULL); then? > > > + local_irq_save(flags); > > What's the purpose of this? > The sched_clock_register() function contains > WARN_ON(!irqs_disabled()); > which I did not want to trigger. That code is run in the early setup with interrupts disabled unless I'm missing something ... Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
