Hey All, So this patch series contains a series of performance optimizations to the dma-buf system heap.
Unfortunately, in working these up, I realized the heap-helpers infrastructure we tried to add to miniimize code duplication is not as generic as we intended. For some heaps it makes sense to deal with page lists, for other heaps it makes more sense to track things with sgtables.
So this series reworks the system heap to use sgtables, and then consolidates the pagelist method from the heap-helpers into the CMA heap. After which the heap-helpers logic is removed (as it is unused). I'd still like to find a better way to avoid some of the logic duplication in implementing the entire dma_buf_ops handlers per heap. But unfortunately that code is tied somewhat to how the buffer's memory is tracked.
After this, the series introduces two optimizations to the the system heap, utilizing large order pages, and adding a page-pool (maybe abusing the pagepool logic from the network code, but it seems silly to reimplement it).
I implemented a simple allocation microbenchmark to compare dmabuf heaps vs ion: https://git.linaro.org/people/john.stultz/android-dev.git/commit/?h=dev/dma-...
With these changes, the allocation path is *much* improved, performing better then ION (though to be fair, the repeated allocating and freeing of the same size buffer is the ideal case for the pagepool logic, so don't read too much into it).
I charted some datapoints from the microbenchmark with each of the patches should folks be interested. https://docs.google.com/spreadsheets/d/1-1C8ZQpmkl_0DISkI6z4xelE08MlNAN7oEu3...
Finally, a port of a patch that Ørjan Eide implemented for ION that avoids calling sync on attachments that don't have a mapping.
Feedback on these would be great!
thanks -john
New in v2: * Fix unused return value and locking issue Reported-by: kernel test robot lkp@intel.com Julia Lawall julia.lawall@inria.fr * Make system_heap_buf_ops static Reported-by: kernel test robot lkp@intel.com * Make cma_heap_buf_ops static suggested by kernel test robot lkp@intel.com * Fix uninitialized return in cma Reported-by: kernel test robot lkp@intel.com * Minor cleanups
Cc: Sumit Semwal sumit.semwal@linaro.org Cc: Liam Mark lmark@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: 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 (6): dma-buf: system_heap: Rework system heap to use sgtables instead of pagelists dma-buf: heaps: Move heap-helper logic into the cma_heap implementation dma-buf: heaps: Remove heap-helpers code dma-buf: system_heap: Allocate higher order pages if available dma-buf: system_heap: Add pagepool support to system heap dma-buf: heaps: Skip sync if not mapped
drivers/dma-buf/heaps/Kconfig | 1 + drivers/dma-buf/heaps/Makefile | 1 - drivers/dma-buf/heaps/cma_heap.c | 328 ++++++++++++++++---- drivers/dma-buf/heaps/heap-helpers.c | 271 ----------------- drivers/dma-buf/heaps/heap-helpers.h | 53 ---- drivers/dma-buf/heaps/system_heap.c | 427 ++++++++++++++++++++++++--- 6 files changed, 659 insertions(+), 422 deletions(-) delete mode 100644 drivers/dma-buf/heaps/heap-helpers.c delete mode 100644 drivers/dma-buf/heaps/heap-helpers.h