[PATCH v5 0/7] dma-buf: Performance improvements for system heap & a system-uncached implementation

[John Stultz]

Hey All,
  So just wanted to send my last revision of my patch series
of performance optimizations to the dma-buf system heap.

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. As more heaps show up I
think we'll have a better idea how to best share code, so for
now I think this is ok.

After this, the series introduces an optimization that
Ørjan Eide implemented for ION that avoids calling sync on
attachments that don't have a mapping.

Next, an optimization to use larger order pages for the system
heap. This change brings us closer to the current performance
of the ION allocation code (though there still is a gap due
to ION using a mix of deferred-freeing and page pools, I'll be
looking at integrating those eventually).

Finally, a reworked version of my uncached system heap
implementation I was submitting a few weeks back. Since it
duplicated a lot of the now reworked system heap code, I
realized it would be much simpler to add the functionality to
the system_heap implementation itself.

While not improving the core allocation performance, the
uncached heap allocations do result in *much* improved
performance on HiKey960 as it avoids a lot of flushing and
invalidating buffers that the cpu doesn't touch often.

Feedback on these would be great!

thanks
-john

New in v5:
* Added a comment explaining why the order sizes are
  chosen as they are

Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Cc: Liam Mark <lmark@xxxxxxxxxxxxxx>
Cc: Laura Abbott <labbott@xxxxxxxxxx>
Cc: Brian Starkey <Brian.Starkey@xxxxxxx>
Cc: Hridya Valsaraju <hridya@xxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Sandeep Patil <sspatil@xxxxxxxxxx>
Cc: Daniel Mentz <danielmentz@xxxxxxxxxx>
Cc: Chris Goldsworthy <cgoldswo@xxxxxxxxxxxxxx>
Cc: Ørjan Eide <orjan.eide@xxxxxxx>
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Cc: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
Cc: Simon Ser <contact@xxxxxxxxxxx>
Cc: James Jones <jajones@xxxxxxxxxx>
Cc: linux-media@xxxxxxxxxxxxxxx
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx

John Stultz (7):
  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: heaps: Skip sync if not mapped
  dma-buf: system_heap: Allocate higher order pages if available
  dma-buf: dma-heap: Keep track of the heap device struct
  dma-buf: system_heap: Add a system-uncached heap re-using the system
    heap

 drivers/dma-buf/dma-heap.c           |  33 +-
 drivers/dma-buf/heaps/Makefile       |   1 -
 drivers/dma-buf/heaps/cma_heap.c     | 324 +++++++++++++++---
 drivers/dma-buf/heaps/heap-helpers.c | 270 ---------------
 drivers/dma-buf/heaps/heap-helpers.h |  53 ---
 drivers/dma-buf/heaps/system_heap.c  | 494 ++++++++++++++++++++++++---
 include/linux/dma-heap.h             |   9 +
 7 files changed, 753 insertions(+), 431 deletions(-)
 delete mode 100644 drivers/dma-buf/heaps/heap-helpers.c
 delete mode 100644 drivers/dma-buf/heaps/heap-helpers.h

-- 
2.17.1