Re: [PATCH v3 11/14] migration/multifd: Replace multifd_send_state->pages with client data

[Peter Xu]

On Thu, Aug 01, 2024 at 09:35:13AM -0300, Fabiano Rosas wrote:
> Multifd currently has a simple scheduling mechanism that distributes
> work to the various channels by keeping storage space within each
> channel and an extra space that is given to the client. Each time the
> client fills the space with data and calls into multifd, that space is
> given to the next idle channel and a free storage space is taken from
> the channel and given to client for the next iteration.
> 
> This means we always need (#multifd_channels + 1) memory slots to
> operate multifd.
> 
> This is fine, except that the presence of this one extra memory slot
> doesn't allow different types of payloads to be processed at the same
> time in different channels, i.e. the data type of
> multifd_send_state->pages needs to be the same as p->pages.
> 
> For each new data type different from MultiFDPage_t that is to be
> handled, this logic would need to be duplicated by adding new fields
> to multifd_send_state, to the channels and to multifd_send_pages().
> 
> Fix this situation by moving the extra slot into the client and using
> only the generic type MultiFDSendData in the multifd core.
> 
> Signed-off-by: Fabiano Rosas <farosas@suse.de>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu