On Tue, Nov 02, 2021 at 08:58:55AM -0700, Chia-I Wu wrote: > On Tue, Nov 2, 2021 at 6:07 AM Gerd Hoffmann <kra...@redhat.com> wrote: > > > > On Tue, Nov 02, 2021 at 12:31:39PM +0100, Maksym Wezdecki wrote: > > > From: mwezdeck <maksym.wezde...@collabora.co.uk> > > > > > > The idea behind the commit: > > > 1. not pin the pages during resource_create ioctl > > > 2. pin the pages on the first use during: > > > - transfer_*_host ioctl > > > - map ioctl > > > > i.e. basically lazy pinning. Approach looks sane to me. > > > > > 3. introduce new ioctl for pinning pages on demand > > > > What is the use case for this ioctl? > > In any case this should be a separate patch. > > Lazy pinning can be a nice optimization that userspace does not > necessarily need to know about. This patch however skips pinning for > execbuffer ioctl and introduces a new pin ioctl instead. That is a > red flag.
Ah, so the pin ioctl is for buffers which need a pin for execbuffer. Yep, that isn't going to fly that way, it'll break old userspace. Lazy pinning must be opt-in, so new userspace which knows about the pin ioctl can enable lazy pinning. One possible way would be to add a flag for the VIRTGPU_RESOURCE_CREATE ioctl, so lazy pinning can be enabled per resource. take care, Gerd _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
