On Thu, Jan 13, 2022 at 04:44:47PM +0100, Stefano Garzarella wrote: > On Thu, Jan 13, 2022 at 10:19:46AM -0500, Michael S. Tsirkin wrote: > > On Thu, Jan 13, 2022 at 03:56:42PM +0100, Stefano Garzarella wrote: > > > In vhost_enable_notify() we enable the notifications and we read > > > the avail index to check if new buffers have become available in > > > the meantime. In this case, the device would go to re-read avail > > > index to access the descriptor. > > > > > > As we already do in other place, we can cache the value in `avail_idx` > > > and compare it with `last_avail_idx` to check if there are new > > > buffers available. > > > > > > Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> > > > > I guess we can ... but what's the point? > > > > That without this patch if avail index is new, then device when will call > vhost_get_vq_desc() will find old value in cache and will read it again. > > With this patch we also do the same path and update the cache every time we > read avail index. > > I marked it RFC because I don't know if it's worth it :-) > > Stefano Pls include info like this in commit log. Thanks! -- MST
