[openstack-dev] [oslo] Issues with POSIX semaphores and other locks in lockutils

Ben Nemec openstack at nemebean.com
Wed Aug 20 20:13:37 UTC 2014


On 08/20/2014 01:03 PM, Vishvananda Ishaya wrote:
> This may be slightly off-topic but it is worth mentioning that the use of threading.Lock[1]
> which was included to make the locks thread safe seems to be leading to a deadlock in eventlet[2].
> It seems like we have rewritten this too many times in order to fix minor pain points and are
> adding risk to a very important component of the system.
> 
> [1] https://review.openstack.org/#/c/54581
> [2] https://bugs.launchpad.net/nova/+bug/1349452

This is pretty much why I'm pushing to just revert to the file locking
behavior we had up until a couple of months ago, rather than
implementing some new shiny lock thing that will probably cause more
subtle issues in the consuming projects.  It's become clear to me that
lockutils is too deeply embedded in the other projects, and there are
too many implementation details that they rely on, to make significant
changes to its default code path.

> 
> On Aug 18, 2014, at 2:05 PM, Pádraig Brady <P at draigBrady.com> wrote:
> 
>> On 08/18/2014 03:38 PM, Julien Danjou wrote:
>>> On Thu, Aug 14 2014, Yuriy Taraday wrote:
>>>
>>> Hi Yuriy,
>>>
>>> […]
>>>
>>>> Looking forward to your opinions.
>>>
>>> This looks like a good summary of the situation.
>>>
>>> I've added a solution E based on pthread, but didn't get very far about
>>> it for now.
>>
>> In my experience I would just go with the fcntl locks.
>> They're auto unlocked and well supported, and importantly,
>> supported for distributed processes.
>>
>> I'm not sure how problematic the lock_path config is TBH.
>> That is adjusted automatically in certain cases where needed anyway.
>>
>> Pádraig.
>>
>> _______________________________________________
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
> 
> 
> 
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
> 




More information about the OpenStack-dev mailing list