On Tue, Mar 17, 2015 at 09:13:02AM +0100, Ingo Molnar wrote: > >* Wanpeng Li <[email protected]> wrote: > >> Hi Ingo, >> On Tue, Mar 17, 2015 at 09:06:13AM +0100, Ingo Molnar wrote: >> > >> >* Wanpeng Li <[email protected]> wrote: >> > >> >> Hi Ingo, >> >> On Mon, Mar 16, 2015 at 04:01:02PM +0100, Ingo Molnar wrote: >> >> >> + >> >> >> + /* >> >> >> + * If cannot preempt any rq, fallback to pick >> >> >> any >> >> >> + * online cpu. >> >> > >> >> >s/If cannot/If we cannot >> >> >s/fallback/fall back >> >> >> >> Will do. >> >> >> >> > >> >> >> + */ >> >> >> + fallback = true; >> >> >> + cpu = cpumask_any_and(cpu_active_mask, >> >> >> + tsk_cpus_allowed(p)); >> >> > >> >> >shouldn't be on separate lines - but this is also a sign that the guts >> >> >> >> Otherwise there is a "WARNING: line over 80 characters". >> > >> >Yes, but did your reaction to that tool's warning improve the code? I >> >don't think so. If do what I suggested and reduce indentation a bit, >> >you'll fix the warning _and_ improve the code. Win-win. >> >> Cool, will do. >> >> > >> >> > of this new code should be in a helper function, not inside >> >> > several layers of branches. >> >> >> >> Do you mean the whole patch should be in a helper function? >> > >> >Probably. >> >> Will do. >> >> > >> >> >> + if (cpu >= nr_cpu_ids) { >> >> >> + if (dl_bandwidth_enabled()) { >> >> >> + /* >> >> >> + * Fail to find any suitable >> >> >> cpu. >> >> >> + * The task will never come >> >> >> back! >> >> >> + */ >> >> >> + WARN_ON(1); >> >> > >> >> > Can this condition happen to users with a non-buggy kernel? >> >> >> >> What do you prefer? ;-) >> > >> >That was a yes/no question: can this condition trigger on correctly >> >working kernels? >> >> How about add unlikely() here? > >Please answer my question: can this condition trigger on correctly >working kernels? I think so, but maybe I'm wrong?
I didn't see it happen, I add this by Juri's suggestion, maybe he can explain more. Ping Juri, ;-) Regards, Wanpeng Li > >Yes/no. > >Thanks, > > Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
