[Devel] [PATCH v4 VZ9 4/5] dm-qcow2: add merge_backward set_eventfd command

[Pavel Tikhomirov]

On 3/5/25 16:42, Alexander Atanasov wrote:
> On 3.03.25 11:37, Pavel Tikhomirov wrote:
>> This eventfd can be used to get an event when merge_backward start work
>> have finished and is waiting for completion.
> 
> What is the benefit of using eventfd versus devicemapper events?

In my understanding the benefit of eventfd compared to qcow2_get_event 
is that we can poll on eventfd but with qcow2_get_event we can only 
busy-wait.

But maybe I'm missing something, is there devicemapper native way to 
poll events?

> 

-- 
Best regards, Pavel Tikhomirov
Senior Software Developer, Virtuozzo.