LWN.net Logo

TTM DMA pool v1.8

From:  Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To:  linux-kernel@vger.kernel.org, thellstrom@vmware.com, dri-devel@lists.freedesktop.org, bskeggs@redhat.com, j.glisse@redhat.com, thomas@shipmail.org, airlied@redhat.com, airlied@linux.ie, alexdeucher@gmail.com
Subject:  [PATCH] TTM DMA pool v1.8
Date:  Thu, 29 Sep 2011 16:33:43 -0400
Message-ID:  <1317328432-25620-1-git-send-email-konrad.wilk@oracle.com>
Cc:  xen-devel@lists.xensource.com
Archive-link:  Article, Thread

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

Way back in January this patchset:
http://lists.freedesktop.org/archives/dri-devel/2011-Janu...
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@shipmail.org 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).

But before I do any of that a second set of eyes taking a look at these
patches would be most welcome.

In regards to testing, I've been running them non-stop for the last month
(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://oss.oracle.com/git/kwilk/xen.git devel/ttm.dma_pool.v1.8

 drivers/gpu/drm/nouveau/nouveau_mem.c    |    8 +-
 drivers/gpu/drm/nouveau/nouveau_sgdma.c  |    3 +-
 drivers/gpu/drm/radeon/radeon_device.c   |    6 +
 drivers/gpu/drm/radeon/radeon_gart.c     |    4 +-
 drivers/gpu/drm/radeon/radeon_ttm.c      |    3 +-
 drivers/gpu/drm/ttm/Makefile             |    3 +
 drivers/gpu/drm/ttm/ttm_bo.c             |    4 +-
 drivers/gpu/drm/ttm/ttm_memory.c         |    5 +
 drivers/gpu/drm/ttm/ttm_page_alloc.c     |   63 ++-
 drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 1317 ++++++++++++++++++++++++++++++
 drivers/gpu/drm/ttm/ttm_tt.c             |    5 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c      |    4 +-
 drivers/xen/swiotlb-xen.c                |    2 +-
 include/drm/ttm/ttm_bo_driver.h          |    7 +-
 include/drm/ttm/ttm_page_alloc.h         |  100 +++-
 include/linux/swiotlb.h                  |    7 +-
 lib/swiotlb.c                            |    5 +-
 17 files changed, 1516 insertions(+), 30 deletions(-)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Copyright © 2011, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds