Re: RBD Async request: When / How are the call back called ?

[Mike Ryan <mike.ryan@inktank.com>]

On Wed, Aug 29, 2012 at 04:57:39PM +0200, Sylvain Munaut wrote:
> How and when will the call back specified in a rbd_completion_t be called ?
> 
> Imagine I do a rbd_aio_write and then do while (1); ... I don't see
> how the library could call my callback unless there is threads
> involved (and then my cb would be called in another thread context
> which is not great ...)

I believe it's called from another thread.

> My problem here is that I need to integrate inside the main loop of
> another software and I can't block, but I still need to be able to
> 'notify' when the requests are over. I can ask the scheduler of that
> main loop to call me on some even on a file descriptor (but I don't
> see any fd here), or to call me periodically (but I don't see any call
> to test for completion without waiting for it).

from include/rados/librados.hpp:

  struct AioCompletion {
    ...
    bool is_complete();
    ...
  };

Is that sufficient?