Re: [PATCH v3 12/31] elx: libefc: Remote node state machine interfaces

James Smart
2020-04-23T18:25:08Z

On 4/23/2020 1:02 AM, Daniel Wagner wrote:
>
> Thanks a lot for this. IMO, this should be added as documentation.
>
>> In IO path, EFC lock is acquired to find the sport and node, release the EFC
>> lock and continue with IO allocation and processing. Note: There is still an
>> unsafe area where we check for 'node->hold_frames" without the lock.
>
> Is this is the fast path? Would RCU help to avoid taking the lock at all?
> The usage pattern sounds like it would be a candidate for RCU.
>
>> Node is
>> assumed to be kept alive until all the IOs under the node are freed. Adding
>> the refcounting will remove this assumption.

I'll see what we can do, and will look at RCU.

BTW: also agreed with your comments in all the remaining patches, so
will address those as well.

Same for Hannes's comments.

-- james