From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Wed, 18 Mar 2015 13:47:59 +0000 (+0100)
Subject: drm/i915: kerneldoc for i915_gem_shrinker.c
X-Git-Tag: omap-for-v4.2/o2_dc~72^2~20^2~67
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eb0b44adc08c0be01a027eb009e9cdadc31e65a2;p=pandora-kernel.git

drm/i915: kerneldoc for i915_gem_shrinker.c

And remove one bogus * from i915_gem_gtt.c since that's not a
kerneldoc there.

v2: Review from Chris:
- Clarify memory space to better distinguish from address space.
- Add note that shrink doesn't guarantee the freed memory and that
  users must fall back to shrink_all.
- Explain how pinning ties in with eviction/shrinker.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---

diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 7a45775518f6..f4976cd7b32b 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -4184,7 +4184,7 @@ int num_ioctls;</synopsis>
       <sect2>
         <title>Buffer Object Eviction</title>
 	<para>
-	  This section documents the interface function for evicting buffer
+	  This section documents the interface functions for evicting buffer
 	  objects to make space available in the virtual gpu address spaces.
 	  Note that this is mostly orthogonal to shrinking buffer objects
 	  caches, which has the goal to make main memory (shared with the gpu
@@ -4192,6 +4192,17 @@ int num_ioctls;</synopsis>
 	</para>
 !Idrivers/gpu/drm/i915/i915_gem_evict.c
       </sect2>
+      <sect2>
+        <title>Buffer Object Memory Shrinking</title>
+	<para>
+	  This section documents the interface function for shrinking memory
+	  usage of buffer object caches. Shrinking is used to make main memory
+	  available.  Note that this is mostly orthogonal to evicting buffer
+	  objects, which has the goal to make space in gpu virtual address
+	  spaces.
+	</para>
+!Idrivers/gpu/drm/i915/i915_gem_shrinker.c
+      </sect2>
     </sect1>
 
     <sect1>
diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index e3a49d94da3a..d09e35ed9c9a 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -63,6 +63,10 @@ mark_free(struct i915_vma *vma, struct list_head *unwind)
  *
  * This function is used by the object/vma binding code.
  *
+ * Since this function is only used to free up virtual address space it only
+ * ignores pinned vmas, and not object where the backing storage itself is
+ * pinned. Hence obj->pages_pin_count does not protect against eviction.
+ *
  * To clarify: This is for freeing up virtual address space, not for freeing
  * memory in e.g. the shrinker.
  */
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