linux/Documentation/DocBook
David Herrmann fe3078fa5c drm: add unified vma offset manager
If we want to map GPU memory into user-space, we need to linearize the
addresses to not confuse mm-core. Currently, GEM and TTM both implement
their own offset-managers to assign a pgoff to each object for user-space
CPU access. GEM uses a hash-table, TTM uses an rbtree.

This patch provides a unified implementation that can be used to replace
both. TTM allows partial mmaps with a given offset, so we cannot use
hashtables as the start address may not be known at mmap time. Hence, we
use the rbtree-implementation of TTM.

We could easily update drm_mm to use an rbtree instead of a linked list
for it's object list and thus drop the rbtree from the vma-manager.
However, this would slow down drm_mm object allocation for all other
use-cases (rbtree insertion) and add another 4-8 bytes to each mm node.
Hence, use the separate tree but allow for later migration.

This is a rewrite of the 2012-proposal by David Airlie <airlied@linux.ie>

v2:
 - fix Docbook integration
 - drop drm_mm_node_linked() and use drm_mm_node_allocated()
 - remove unjustified likely/unlikely usage (but keep for rbtree paths)
 - remove BUG_ON() as drm_mm already does that
 - clarify page-based vs. byte-based addresses
 - use drm_vma_node_reset() for initialization, too
v4:
 - allow external locking via drm_vma_offset_un/lock_lookup()
 - add locked lookup helper drm_vma_offset_lookup_locked()
v5:
 - fix drm_vma_offset_lookup() to correctly validate range-mismatches
   (fix (offset > start + pages))
 - fix drm_vma_offset_exact_lookup() to actually do what it says
 - remove redundant vm_pages member (add drm_vma_node_size() helper)
 - remove unneeded goto
 - fix documentation

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@gmail.com>
2013-07-25 20:47:04 +10:00
..
media Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media 2013-07-13 12:09:57 -07:00
.gitignore
80211.tmpl wireless: fix kernel-doc 2013-06-05 09:33:32 +02:00
alsa-driver-api.tmpl
debugobjects.tmpl
device-drivers.tmpl Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2013-07-09 16:04:31 -07:00
deviceiobook.tmpl
drm.tmpl drm: add unified vma offset manager 2013-07-25 20:47:04 +10:00
filesystems.tmpl
gadget.tmpl
genericirq.tmpl genirq: Add the generic chip to the genirq docbook 2013-06-28 12:56:04 +02:00
kernel-api.tmpl
kernel-hacking.tmpl
kernel-locking.tmpl docbook: add futexes to kernel-locking docbook 2013-07-03 16:08:01 -07:00
kgdb.tmpl
libata.tmpl
librs.tmpl
lsm.tmpl
Makefile
media_api.tmpl
mtdnand.tmpl
networking.tmpl
rapidio.tmpl
regulator.tmpl
s390-drivers.tmpl
scsi.tmpl
sh.tmpl
stylesheet.xsl
tracepoint.tmpl
uio-howto.tmpl
usb.tmpl
writing_usb_driver.tmpl
writing-an-alsa-driver.tmpl
z8530book.tmpl