On Thu 13-04-23 09:16:58, Jaewon Kim wrote: > >On Wed, Apr 12, 2023 at 4:38?AM Jaewon Kim <jaewon31.kim@xxxxxxxxxxx> wrote: > > > >> Yes I think you're right. As a allocator, dma-buf system heap looks to be loose > >> in memory allocation. Limiting dmabuf memory may be required. But I think there > >> is no nice and reasonable way so far. And the dma-buf system heap is being > >> widely used in Android mobile system. AFAIK the camera consumes huge memory > >> through this dma-buf system heap. I actually even looked a huge size request > >> over 2GB in one dma-buf request. > >> > >Hey can you point me to where you saw a request that big? That's a > >non-buggy request?! > > (let me resend as plain text) > It was one of camera scenarios. I internally asked and heard that was not a bug > but normal. I think 2GB looks too big for one graphics buffer but it could be > for other purposes like camera. I think the system heap should support that. Is that any of the upstream drivers or something sitting out of the tree. > Regarding __GFP_RETRY_MAYFAIL, we may need to say dma-buf system heap was > designed to gather many pages up to a requested size. If mm returns NULL due to > __GFP_RETRY_MAYFAIL, dma-buf system heap will release other already allocated > pages, so that it may help to avoid oom. This really depends on the other activity on the system. If you have a more concurrent memory demand at the time then you might be just out of the luck. Really, claiming huge portion of the memory shouldn't be done nilly willy. -- Michal Hocko SUSE Labs
