Messages in this thread | | | Subject | Re: [RFC][PATCH v6 0/7] Generic page pool & deferred freeing for system dmabuf heap | From | Christian König <> | Date | Fri, 5 Feb 2021 11:36:01 +0100 |
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Am 05.02.21 um 09:06 schrieb John Stultz: > This series is starting to get long, so I figured I'd add a > short cover letter for context. > > The point of this series is trying to add both deferred-freeing > logic as well as a page pool to the DMA-BUF system heap. > > This is desired, as the combination of deferred freeing along > with the page pool allows us to offload page-zeroing out of > the allocation hot path. This was done originally with ION > and this patch series allows the DMA-BUF system heap to match > ION's system heap allocation performance in a simple > microbenchmark [1] (ION re-added to the kernel for comparision, > running on an x86 vm image): > > ./dmabuf-heap-bench -i 0 1 system > Testing dmabuf system vs ion heaptype 0 (flags: 0x1) > --------------------------------------------- > dmabuf heap: alloc 4096 bytes 5000 times in 86572223 ns 17314 ns/call > ion heap: alloc 4096 bytes 5000 times in 97442526 ns 19488 ns/call > dmabuf heap: alloc 1048576 bytes 5000 times in 196635057 ns 39327 ns/call > ion heap: alloc 1048576 bytes 5000 times in 357323629 ns 71464 ns/call > dmabuf heap: alloc 8388608 bytes 5000 times in 3165445534 ns 633089 ns/call > ion heap: alloc 8388608 bytes 5000 times in 3699591271 ns 739918 ns/call > dmabuf heap: alloc 33554432 bytes 5000 times in 13327402517 ns 2665480 ns/call > ion heap: alloc 33554432 bytes 5000 times in 15292352796 ns 3058470 ns/call > > Daniel didn't like earlier attempts to re-use the network > page-pool code to achieve this, and suggested the ttm_pool be > used instead. This required pulling the fairly tightly knit > ttm_pool logic apart, but after many failed attmempts I think > I found a workable abstraction to split out shared logic. > > So this series contains a new generic drm_page_pool helper > library, converts the ttm_pool to use it, and then adds the > dmabuf deferred freeing and adds support to the dmabuf system > heap to use both deferred freeing and the new drm_page_pool. > > Input would be greatly appreciated. Testing as well, as I don't > have any development hardware that utilizes the ttm pool.
We can easily do the testing and the general idea sounds solid to me.
I see three major things we need to clean up here. 1. The licensing, you are moving from BSD/MIT to GPL2. 2. Don't add any new overhead to the TTM pool, especially allocating a private object per page is a no-go. 3. What are you doing with the reclaim stuff and why? 4. Keeping the documentation would be nice to have.
Regards, Christian.
> > thanks > -john > > [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fandroid.googlesource.com%2Fplatform%2Fsystem%2Fmemory%2Flibdmabufheap%2F%2B%2Frefs%2Fheads%2Fmaster%2Ftests%2Fdmabuf_heap_bench.c&data=04%7C01%7Cchristian.koenig%40amd.com%7C2dc4d6cb3ee246558b9e08d8c9acef9a%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637481091933715561%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=oMgVsrdlwS%2BqZuuatjTiWDzMU9SiUW5eRar5xwT%2BHYQ%3D&reserved=0 > > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: Christian Koenig <christian.koenig@amd.com> > Cc: Sumit Semwal <sumit.semwal@linaro.org> > Cc: Liam Mark <lmark@codeaurora.org> > Cc: Chris Goldsworthy <cgoldswo@codeaurora.org> > Cc: Laura Abbott <labbott@kernel.org> > Cc: Brian Starkey <Brian.Starkey@arm.com> > Cc: Hridya Valsaraju <hridya@google.com> > Cc: Suren Baghdasaryan <surenb@google.com> > Cc: Sandeep Patil <sspatil@google.com> > Cc: Daniel Mentz <danielmentz@google.com> > Cc: Ørjan Eide <orjan.eide@arm.com> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Ezequiel Garcia <ezequiel@collabora.com> > Cc: Simon Ser <contact@emersion.fr> > Cc: James Jones <jajones@nvidia.com> > Cc: linux-media@vger.kernel.org > Cc: dri-devel@lists.freedesktop.org > > John Stultz (7): > drm: Add a sharable drm page-pool implementation > drm: ttm_pool: Rename the ttm_pool_dma structure to ttm_pool_page_dat > drm: ttm_pool: Rework ttm_pool_free_page to allow us to use it as a > function pointer > drm: ttm_pool: Rework ttm_pool to use drm_page_pool > dma-buf: heaps: Add deferred-free-helper library code > dma-buf: system_heap: Add drm pagepool support to system heap > dma-buf: system_heap: Add deferred freeing to the system heap > > drivers/dma-buf/heaps/Kconfig | 5 + > drivers/dma-buf/heaps/Makefile | 1 + > drivers/dma-buf/heaps/deferred-free-helper.c | 145 ++++++++++ > drivers/dma-buf/heaps/deferred-free-helper.h | 55 ++++ > drivers/dma-buf/heaps/system_heap.c | 77 ++++- > drivers/gpu/drm/Kconfig | 5 + > drivers/gpu/drm/Makefile | 1 + > drivers/gpu/drm/page_pool.c | 220 +++++++++++++++ > drivers/gpu/drm/ttm/ttm_pool.c | 278 ++++++------------- > include/drm/page_pool.h | 54 ++++ > include/drm/ttm/ttm_pool.h | 23 +- > 11 files changed, 639 insertions(+), 225 deletions(-) > create mode 100644 drivers/dma-buf/heaps/deferred-free-helper.c > create mode 100644 drivers/dma-buf/heaps/deferred-free-helper.h > create mode 100644 drivers/gpu/drm/page_pool.c > create mode 100644 include/drm/page_pool.h >
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