On 05/14/2013 01:50 PM, Bjørn Mork wrote: > "Srivatsa S. Bhat" <[email protected]> writes: >> On 05/14/2013 01:08 PM, Bjørn Mork wrote: >>> "Srivatsa S. Bhat" <[email protected]> writes: >>> >>>> The problem appears to be in the cpu idle poll implementation. You can >>>> trigger >>>> this problem by passing idle=poll in the kernel cmd-line as well, right? >>> >>> That sounded so obvious that it made me think "Doh, why didn't I just >>> test that before?" But unfortunately there must be some other factor >>> involved. No warnings observed during normal use when running with >>> idle=poll: >>> >> >> I didn't expect warnings with normal use. >> >>> bjorn@nemi:~$ dmesg|grep polling >>> [ 0.000000] process: using polling idle threads >>> >>> >>> I expected a flood of warnings here, but there is none until I start >>> powertop (to confirm that the original issue is still there). So it's >>> more than just entering cpu_idle_poll(). >>> >> >> Yeah, of course it is :-) The warning triggers only when you enable the >> tracepoint >> in the idle code. And in your case, powertop does that. That's why it only >> triggers when you run powertop. Alternatively, if you enable the tracepoint >> yourself manually, I bet you'll see the warnings, even without using >> powertop. > > Ah, right. That sounds so obvious I have to go "Doh!" again:) >
:-) >>>> I think I understand what is going on here. Can you please try the fix >>>> below? >>>> (It is only compile-tested since its very late here and I really need to >>>> get >>>> some sleep!). >>> >>> Works perfect. Thanks. >> >> Thanks for your testing! >> >>> I assume this is the correct fix even if the >>> problem isn't completely understood? >>> >> >> Hmm? Why do you say the problem isn't completely understood? I thought I >> explained the problem in my changelog. Did I miss something? > > No, I did. I didn't understand the tracepoint part of this. But it is > all perfectly clear to me too now, after your excellent explanation > above. > Great! Thanks :) Regards, Srivatsa S. Bhat -- 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/
