On Dienstag, 5. Oktober 2021 13:24:36 CEST Michael S. Tsirkin wrote: > On Tue, Oct 05, 2021 at 01:17:59PM +0200, Christian Schoenebeck wrote: > > On Dienstag, 5. Oktober 2021 09:16:07 CEST Michael S. Tsirkin wrote: > > > On Mon, Oct 04, 2021 at 09:38:08PM +0200, Christian Schoenebeck wrote: > > > > Raise the maximum possible virtio transfer size to 128M > > > > (more precisely: 32k * PAGE_SIZE). See previous commit for a > > > > more detailed explanation for the reasons of this change. > > > > > > > > For not breaking any virtio user, all virtio users transition > > > > to using the new macro VIRTQUEUE_LEGACY_MAX_SIZE instead of > > > > VIRTQUEUE_MAX_SIZE, so they are all still using the old value > > > > of 1k with this commit. > > > > > > > > On the long-term, each virtio user should subsequently either > > > > switch from VIRTQUEUE_LEGACY_MAX_SIZE to VIRTQUEUE_MAX_SIZE > > > > after checking that they support the new value of 32k, or > > > > otherwise they should replace the VIRTQUEUE_LEGACY_MAX_SIZE > > > > macro by an appropriate value supported by them. > > > > > > > > Signed-off-by: Christian Schoenebeck <qemu_...@crudebyte.com> > > > > > > I don't think we need this. Legacy isn't descriptive either. Just leave > > > VIRTQUEUE_MAX_SIZE alone, and come up with a new name for 32k. > > > > Does this mean you disagree that on the long-term all virtio users should > > transition either to the new upper limit of 32k max queue size or > > introduce > > their own limit at their end? > > depends. if 9pfs is the only one unhappy, we can keep 4k as > the default. it's sure a safe one. > > > Independent of the name, and I would appreciate for suggestions for an > > adequate macro name here, I still think this new limit should be placed in > > the shared virtio.h file. Because this value is not something invented on > > virtio user side. It rather reflects the theoretical upper limited > > possible with the virtio protocol, which is and will be common for all > > virtio users. > We can add this to the linux uapi headers, sure.
Well, then I wait for few days, and if nobody else cares about this issue, then I just hard code 32k on 9pfs side exclusively in v3 for now and that's it. Best regards, Christian Schoenebeck
