Re: [patch] Real-Time Preemption, -RT-2.6.12-rc4-V0.7.47-06

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



* Michal Schmidt <[email protected]> wrote:

> Yes, I'm going to contact upstream about this. However, after closer 
> look on cpufreq code I came to a conclusion that the lock there 
> doesn't really play the role of a completion. There's always: down(), 
> then do something with the data structure, then up() in the same 
> function. I'm going to fix it differently after consulting with 
> upstream author (I now think that it should not be necessary to take 
> the lock in cpufreq_add_dev at all).

yeah. It would lead to incorrect code to use a completion if the purpose 
is a real lock. The main non-PREEMPT_RT-compatible use of semaphores is 
the unlocking of a semaphore the task did not lock itself. It is correct 
Linux code, so that alone is not a good reason to change upstream (and 
upstream doesnt and shouldnt bother about PREEMPT_RT at this point) - 
but if the underlying code is not entirely clean and the cross-owner-use 
of locks is not justified it might be possible to solve this via a 
cleanup.

	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/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux