[Ocfs2-devel] [RFC] ocfs2: a method to prevent lock on the blocked queue is starved.

[Ocfs2-devel] [RFC] ocfs2: a method to prevent lock on the blocked queue is starved.

[jiangyiwen]

In dlm_shuffle_lists, if there are conversions still blocked on the
converting queue all the time, the blocked locks on the blocked queue
can never be processed, so the locks on the blocked queue will be
starved.

So I have an idea to solve this problem: To switch the priority between
the converting queue and blocked queue, i.e. process the locks on the
blocked queue first. In this way, the lock on the blocked queue will
be processed and it will not enter the blocked queue until the
lockres is purged. so the scenario above will be solved.

Anyone has better ideas or advices?

Thanks,
Yiwen Jiang

[Ocfs2-devel] [RFC] ocfs2: a method to prevent lock on the blocked queue is starved.

[Joseph Qi]

Simply switch converting list and blocked list cannot resolve the
starvation case fundamentally.
Maybe we have to set a deadline and bring in a scheduler strategy.
@Junxiao, do you have any other idea?

On 2015/8/27 20:11, jiangyiwen wrote:
> In dlm_shuffle_lists, if there are conversions still blocked on the
> converting queue all the time, the blocked locks on the blocked queue
> can never be processed, so the locks on the blocked queue will be
> starved.
> 
> So I have an idea to solve this problem: To switch the priority between
> the converting queue and blocked queue, i.e. process the locks on the
> blocked queue first. In this way, the lock on the blocked queue will
> be processed and it will not enter the blocked queue until the
> lockres is purged. so the scenario above will be solved.
> 
> Anyone has better ideas or advices?
> 
> Thanks,
> Yiwen Jiang
> 
> 
> .
>