On Tue, Sep 22, 2015 at 02:28:25PM +0200, Paolo Bonzini wrote: > > > On 22/09/2015 14:24, Daniel P. Berrange wrote: > > On Tue, Sep 22, 2015 at 02:19:27PM +0200, Paolo Bonzini wrote: > >> > >> > >> On 18/09/2015 15:19, Daniel P. Berrange wrote: > >>> + QIO_CHANNEL_FEATURE_FD_PASS = (1 << 0), > >>> + QIO_CHANNEL_FEATURE_SHUTDOWN = (1 << 1), > >>> + QIO_CHANNEL_FEATURE_DELAY = (1 << 2), > >>> + QIO_CHANNEL_FEATURE_CORK = (1 << 3), > >> > >> TCP_NODELAY and TCP_CORK are just hints; I think it is okay to just > >> ignore them if not supported. You obviously disagree, so the question > >> is why? :) > > > > Well I was just trying not to second guess what future uses we might > > have of the QIOChannel API, so I went for the approach of providing a > > way to probe any optional features upfront. Code doesn't have to use > > this if it doesn't want to - it can just ignore errors from the API > > call later. > > Perhaps we can get to a middle ground where you can probe them but no > errors are reported? > > Reporting errors is relatively heavyweight (g_new, possibly in a hot > path if the corresponding feature is not supported) and in general QEMU > never checked for the return value of socket_set_cork and > socket_set_nodelay. > > The probe, however, should also test if SOL_TCP and TCP_CORK are > defined. I think corking is a Linux-ism.
Having slept on it now, I think I'll just remove these two feature flags and make the methods void with no error reporting. We can always add feature probing back at a later date if it becomes clearly required. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
