[PATCH] TTM DMA pool v2.2 or [GIT PULL] (stable/ttm.dma_pool.v2.3) for 3.3

From: Konrad Rzeszutek Wilk
Date: Tue Nov 01 2011 - 15:02:51 EST


I am not sure what the right way to patches in Dave tree is for Linux 3.3, so I
am posting the patches and also providing the means of doing a git pull.

The git tree is:

git pull git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git stable/ttm.dma_pool.v2.3


Oh, and Thomas, should I add your Ack on the patches as well? I think it was an implied
Ack, but I do not want to presume. If so, I can respin this with your Ack shortly.

and it has since v2.1: https://lwn.net/Articles/463815/
- Fixed bugs/mistakes pointed out by Jerome
- Added Review-by: Jereme Glisse
Since v2.0: [not posted]
- Redid the registration/override to be tightly integrated with the
'struct ttm_backend_func' per Thomas's suggestion.
Since v1.9: [not posted]
- Performance improvements - it was doing O(n^2) instead of O(n) on certain
workloads.
Since v1.8: [lwn.net/Articles/458724/]
- Removed swiotlb_enabled and used swiotlb_nr_tbl.
- Added callback for changing cache types.
Since v1.7: [https://lkml.org/lkml/2011/8/30/460]
- Fixed checking the DMA address in radeon/nouveau code.
Since v1: [http://lwn.net/Articles/456246/]
- Ran it through the gauntlet of SubmitChecklist and fixed issues
- Made radeon/nouveau driver set coherent_dma (which is required for dmapool)

[.. and this is what I said in v1 post]:

Way back in January this patchset:
http://lists.freedesktop.org/archives/dri-devel/2011-January/006905.html
was merged in, but pieces of it had to be reverted b/c they did not
work properly under PowerPC, ARM, and when swapping out pages to disk.

After a bit of discussion on the mailing list
http://marc.info/?i=4D769726.2030307@xxxxxxxxxxxx I started working on it, but
got waylaid by other things .. and finally I am able to post the RFC patches.

There was a lot of discussion about it and I am not sure if I captured
everybody's thoughts - if I did not - that is _not_ intentional - it has just
been quite some time..

Anyhow .. the patches explore what the "lib/dmapool.c" does - which is to have a
DMA pool that the device has associated with. I kind of married that code
along with drivers/gpu/drm/ttm/ttm_page_alloc.c to create a TTM DMA pool code.
The end result is DMA pool with extra features: can do write-combine, uncached,
writeback (and tracks them and sets back to WB when freed); tracks "cached"
pages that don't really need to be returned to a pool; and hooks up to
the shrinker code so that the pools can be shrunk.

If you guys think this set of patches make sense - my future plans were
1) Get this in large crowd of testing .. and if it works for a kernel release
2) to move a bulk of this in the lib/dmapool.c (I spoke with Matthew Wilcox
about it and he is OK as long as I don't introduce performance regressions).

In regards to testing, I've been running them non-stop for the last two months.
(and found some issues which I've fixed up) - and been quite happy with how
they work.

Michel (thanks!) took a spin of the patches on his PowerPC and they did not
cause any regressions (wheew).

The patches are also located in a git tree:

git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git stable/ttm.dma_pool.v2.3

Konrad Rzeszutek Wilk (11):
swiotlb: Expose swiotlb_nr_tlb function to modules
nouveau/radeon: Set coherent DMA mask
ttm/radeon/nouveau: Check the DMA address from TTM against known value.
ttm: Wrap ttm_[put|get]_pages and extract GFP_* and caching states from 'struct ttm_tt'
ttm: Get rid of temporary scaffolding
ttm/driver: Expand ttm_backend_func to include two overrides for TTM page pool.
ttm: Do not set the ttm->be to NULL before calling the TTM page pool to free pages.
ttm: Provide DMA aware TTM page pool code.
ttm: Add 'no_dma' parameter to turn the TTM DMA pool off during runtime.
nouveau/ttm/dma: Enable the TTM DMA pool if device can only do 32-bit DMA.
radeon/ttm/dma: Enable the TTM DMA pool if the device can only do 32-bit.

drivers/gpu/drm/nouveau/nouveau_debugfs.c | 1 +
drivers/gpu/drm/nouveau/nouveau_mem.c | 5 +
drivers/gpu/drm/nouveau/nouveau_sgdma.c | 8 +-
drivers/gpu/drm/radeon/radeon_device.c | 6 +
drivers/gpu/drm/radeon/radeon_gart.c | 4 +-
drivers/gpu/drm/radeon/radeon_ttm.c | 19 +-
drivers/gpu/drm/ttm/Makefile | 3 +
drivers/gpu/drm/ttm/ttm_memory.c | 5 +
drivers/gpu/drm/ttm/ttm_page_alloc.c | 108 ++-
drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 1409 +++++++++++++++++++++++++++++
drivers/gpu/drm/ttm/ttm_tt.c | 21 +-
drivers/xen/swiotlb-xen.c | 2 +-
include/drm/ttm/ttm_bo_driver.h | 31 +
include/drm/ttm/ttm_page_alloc.h | 53 +-
include/linux/swiotlb.h | 2 +-
lib/swiotlb.c | 5 +-
16 files changed, 1600 insertions(+), 82 deletions(-)
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