On Tue, Jun 21, 2022 at 12:35:54AM -0300, Leonardo Brás wrote: > > This reminded me - Leo, have you considered adding the patch altogether to > > detect the "fallback to non-zero-copy" condition? Because when with it and > > when the fallback happens at some point (e.g. when the guest memory is > > larger than some value) we'll know. > > I still did not consider that, but sure, how do you see that working? > > We can't just disable zero-copy-send because the user actually opted in, so we > could instead add a one time error message for when it falls back to copying, > as > it should happen in the first try of zero-copy send. > > Or we could fail the migration, stating the interface does not support > MSG_ZEROCOPY, since it should happen in the first sendmsg(). > > I would personally opt for the last option. > > What do you think?
I don't have a very strong feeling on it, but yes that sounds proper to me. If one day we'll like zero-copy send be on by default then we'll consider the other way round, but maybe not necessary for now. Thanks. -- Peter Xu
