On Thu, Jul 04, 2019 at 12:17:48PM -0700, Chia-I Wu wrote: > On Thu, Jul 4, 2019 at 4:10 AM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote: > > > > Hi, > > > > > > - r = ttm_bo_reserve(&bo->tbo, true, false, NULL); > > > > + r = reservation_object_lock_interruptible(bo->gem_base.resv, NULL); > > > Can you elaborate a bit about how TTM keeps the BOs alive in, for > > > example, virtio_gpu_transfer_from_host_ioctl? In that function, only > > > three TTM functions are called: ttm_bo_reserve, ttm_bo_validate, and > > > ttm_bo_unreserve. I am curious how they keep the BO alive. > > > > It can't go away between reserve and unreserve, and I think it also > > can't be evicted then. Havn't checked how ttm implements that. > Hm, but the vbuf using the BO outlives the reserve/unreserve section. > The NO_EVICT flag applies only when the BO is still alive. Someone > needs to hold a reference to the BO to keep it alive, otherwise the BO > can go away before the vbuf is retired. Note that patches 14+15 rework virtio_gpu_transfer_*_ioctl to keep gem reference until the command is finished and patch 17 drops virtio_gpu_object_{reserve,unreserve} altogether. Maybe I should try to reorder the series, then squash 6+17 to reduce confusion. I suspect that'll cause quite a few conflicts though ... cheers, Gerd _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel