> From: Zhu, Lingshan <lingshan.zhu@xxxxxxxxx> > Sent: Tuesday, July 26, 2022 10:53 PM > > On 7/27/2022 10:17 AM, Parav Pandit wrote: > >> From: Zhu, Lingshan <lingshan.zhu@xxxxxxxxx> > >> Sent: Tuesday, July 26, 2022 10:15 PM > >> > >> On 7/26/2022 11:56 PM, Parav Pandit wrote: > >>>> From: Zhu, Lingshan <lingshan.zhu@xxxxxxxxx> > >>>> Sent: Tuesday, July 12, 2022 11:46 PM > >>>>> When the user space which invokes netlink commands, detects that > >> _MQ > >>>> is not supported, hence it takes max_queue_pair = 1 by itself. > >>>> I think the kernel module have all necessary information and it is > >>>> the only one which have precise information of a device, so it > >>>> should answer precisely than let the user space guess. The kernel > >>>> module should be reliable than stay silent, leave the question to > >>>> the user space > >> tool. > >>> Kernel is reliable. It doesn’t expose a config space field if the > >>> field doesn’t > >> exist regardless of field should have default or no default. > >> so when you know it is one queue pair, you should answer one, not try > >> to guess. > >>> User space should not guess either. User space gets to see if _MQ > >> present/not present. If _MQ present than get reliable data from kernel. > >>> If _MQ not present, it means this device has one VQ pair. > >> it is still a guess, right? And all user space tools implemented this > >> feature need to guess > > No. it is not a guess. > > It is explicitly checking the _MQ feature and deriving the value. > > The code you proposed will be present in the user space. > > It will be uniform for _MQ and 10 other features that are present now and > in the future. > MQ and other features like RSS are different. If there is no _RSS_XX, there > are no attributes like max_rss_key_size, and there is not a default value. > But for MQ, we know it has to be 1 wihtout _MQ. "we" = user space. To keep the consistency among all the config space fields. > > For feature X, kernel reports default and for feature Y, kernel skip > reporting it, because there is no default. <- This is what we are trying to > avoid here. > Kernel reports one queue pair because there is actually one. > > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
