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Subject[RESEND][PATCH v4 0/7] dma-buf: Performance improvements for system heap & a system-uncached implementation
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Hey All,
So just wanted to resend 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 v4:
* Make sys_heap static (indirectly) Reported-by:
kernel test robot <lkp@intel.com>
* Spelling fixes suggested by BrianS
* Make sys_uncached_heap static, as
Reported-by: kernel test robot <lkp@intel.com>
* Fix wrong return value, caught by smatch
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
* Ensure we call flush/invalidate_kernel_vmap_range() in the
uncached cases to try to address feedback about VIVT caches
from Christoph
* Reorder a few lines as suggested by BrianS
* Avoid holding the initial mapping for the lifetime of the buffer
as suggested by BrianS
* Fix a unlikely race between allocate and updating the dma_mask
that BrianS noticed.

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: Daniel Mentz <danielmentz@google.com>
Cc: Chris Goldsworthy <cgoldswo@codeaurora.org>
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):
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 | 488 ++++++++++++++++++++++++---
include/linux/dma-heap.h | 9 +
7 files changed, 747 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

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