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authorDavid Herrmann <dh.herrmann@gmail.com>2013-07-24 21:06:15 +0200
committerDave Airlie <airlied@gmail.com>2013-07-25 20:47:04 +1000
commitfe3078fa5c367186c94a6652581ffbe9ccea4640 (patch)
treedebadcf6f354b68b76460731ad8845238e042919 /Documentation/DocBook
parent85d9cb41db3bf0f36c999c2e547b37cb9f32367b (diff)
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>
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r--Documentation/DocBook/drm.tmpl6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 7d1278e7a434..87e22ecd9281 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -2212,6 +2212,12 @@ void intel_crt_init(struct drm_device *dev)
!Iinclude/drm/drm_rect.h
!Edrivers/gpu/drm/drm_rect.c
</sect2>
+ <sect2>
+ <title>VMA Offset Manager</title>
+!Pdrivers/gpu/drm/drm_vma_manager.c vma offset manager
+!Edrivers/gpu/drm/drm_vma_manager.c
+!Iinclude/drm/drm_vma_manager.h
+ </sect2>
</sect1>
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