On Fri, Dec 13, 2024 at 05:06:05PM +0100, Maarten Lankhorst wrote: > Hey, > > Den 2024-12-13 kl. 16:21, skrev Maxime Ripard: > > On Fri, Dec 13, 2024 at 03:53:13PM +0100, Maarten Lankhorst wrote: > > > > > > > > > Den 2024-12-13 kl. 14:03, skrev Maxime Ripard: > > > > Hi, > > > > > > > > Thanks for the new update! > > > > > > > > On Wed, Dec 04, 2024 at 02:44:00PM +0100, Maarten Lankhorst wrote: > > > > > New update. Instead of calling it the 'dev' cgroup, it's now the > > > > > 'dmem' cgroup. > > > > > > > > > > Because it only deals with memory regions, the UAPI has been updated > > > > > to use dmem.min/low/max/current, and to make the API cleaner, the > > > > > names are changed too. > > > > > > > > The API is much nicer, and fits much better into other frameworks too. > > > > > > > > > dmem.current could contain a line like: > > > > > "drm/0000:03:00.0/vram0 1073741824" > > > > > > > > > > But I think using "drm/card0/vram0" instead of PCIID would perhaps be > > > > > good too. I'm open to changing it to that based on feedback. > > > > > > > > Do we have any sort of guarantee over the name card0 being stable across > > > > reboots? > > > > > > > > I also wonder if we should have a "total" device that limits the amount > > > > of memory we can allocate from any region? > > > > > > I don't think it is useful. Say your app can use 1 GB of main memory or 2 GB > > > of VRAM, it wouldn't make sense to limit the total of those. In a lot of > > > cases there is only 1 region, so the total of that would still be the same. > > > > > > On top, we just separated the management of each region, adding a 'total' > > > would require unseparating it again. :-) > > > > I didn't mean the total for a device, but for the system. It would > > definitely not make sense for a VRAM, but for CMA for example, you have > > a single, limited, allocator that will be accessible from heaps, v4l2 > > and DRM devices. > > > > If an application has to allocate both from v4l2 and DRM buffers, we > > should be able to limit its total usage of CMA, not just on a single > > device. > > In this case, I think it makes more sense if CMA creates a region, then use > that region in both v4l2 and DRM instead of a separate region for both, with > CMA being responsible for lifetime. Ack, thanks for your feedback :) Maxime
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