Re: [PATCH v3 1/3] rtmutex: update rt-mutex-design

[Alex Shi]

Hi Steven,

Thanks a lot for detailed review. Every suggestion were token except one need
extra review: the 'Waking up in loop'. Is this OK or need more further change?

BTW, I didn't add you on Reviewers, since you are author already. :)


Best regards
Alex


On 07/04/2017 02:49 AM, Steven Rostedt wrote:
>> +In the first case, the task will try again to acquire the lock. If it
> 
> Hmm, I know you mention it below, but it is confusing. In both cases
> the task will try again to acquire the lock. The difference between the
> two cases is what happens if it fails to acquire the lock.
> 
> This part should be rewritten.
> 

+The task can then wake up for a couple of reasons:
+  1) The previous lock owner released the lock, and the task now is top_waiter
+  2) we received a signal or timeout

+In both cases, the task will try again to acquire the lock. If it
+does, then it will take itself off the waiters tree and set itself back
+to the TASK_RUNNING state.

+In first case, if the lock was acquired by another task before this task
+could get the lock, then it will go back to sleep and wait to be woken again.

+The second case is only applicable for tasks that are grabbing a mutex
+that can wake up before getting the lock, either due to a signal or
+a timeout (i.e. rt_mutex_timed_futex_lock()). When woken, it will try to
+take the lock again, if it succeeds, then the task will return with the
+lock held, otherwise it will return with -EINTR if the task was woken
+by a signal, or -ETIMEDOUT if it timed out.

....

-Reviewers:  Ingo Molnar, Thomas Gleixner, Thomas Duetsch, and Randy Dunlap
+Reviewers:  Ingo Molnar, Thomas Gleixner, Thomas Duetsch, Randy Dunlap
+               and Sebastian Siewior


Changed patch:
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