Re: [PATCH v4 3/3] migration/multifd: Report to user when zerocopy not working

[Peter Xu]

On Mon, Jul 11, 2022 at 06:11:13PM -0300, Leonardo Bras wrote:
> Some errors, like the lack of Scatter-Gather support by the network
> interface(NETIF_F_SG) may cause sendmsg(...,MSG_ZEROCOPY) to fail on using
> zero-copy, which causes it to fall back to the default copying mechanism.
> 
> After each full dirty-bitmap scan there should be a zero-copy flush
> happening, which checks for errors each of the previous calls to
> sendmsg(...,MSG_ZEROCOPY). If all of them failed to use zero-copy, then
> increment dirty_sync_missed_zero_copy migration stat to let the user know
> about it.
> 
> Signed-off-by: Leonardo Bras <leobras@redhat.com>
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

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

-- 
Peter Xu