Re: [PATCH v3 3/3] migration/multifd: Warn user when zerocopy not working

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Jul 04, 2022 at 05:23:15PM -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>
> ---
>  migration/ram.h     | 2 ++
>  migration/multifd.c | 2 ++
>  migration/ram.c     | 5 +++++
>  3 files changed, 9 insertions(+)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


With regards,
Daniel
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