On Thu, 24 Sep 2020 at 22:42, Christian König <christian.koenig@xxxxxxx> wrote: > > Am 24.09.20 um 07:18 schrieb Dave Airlie: > > From: Dave Airlie <airlied@xxxxxxxxxx> > > > > All the accel moves do the same pattern here, provide a helper > > And exactly that pattern I want to get away from. Currently this is just refactoring out the helper code in each driver, but I see since it calls bo_mem_space we are probably moving a bit in the wrong direction. > See what happens if we (for example) have a VRAM -> SYSTEM move is the > following: > > 1. TTM allocates a new ttm_resource object in the SYSTEM domain. > 2. We call the driver to move from VRAM to SYSTEM. > 3. Driver finds that it can't do this and calls TTM to allocate GTT. > 4. Since we are maybe out of GTT TTM evicts a different BO from GTT to > SYSTEM and call driver again. > > This is a horrible ping/pong between driver/TTM/driver/TTM/driver and we > should stop that immediately. > > My suggestion is that we rewrite how drivers call the ttm_bo_validate() > function so that we can guarantee that this never happens. > > What do you think? I think that is likely the next step I'd like to take after this refactor, it's a lot bigger, and I'm not sure how it will look yet. Do we envision the driver calling validate in a loop but when it can't find space it tells the driver and the driver does eviction and recalls validate? Dave. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
