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.
thanks -john
[1] https://android.googlesource.com/platform/system/memory/libdmabufheap/+/refs...
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