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Commit c2c1d491 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/i915: Kerneldoc for i915_gem_evict.c 



Request by Ben Widawsky in his review of a patch touching this code.

v2: Clarify the disdinction between evicting vmas (to free up virtual
address space) and evicting objects (to free up actual system memory).
Suggested by Ben.

Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Acked-by: default avatarBen Widawsky <benjamin.widawsky@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 3036537d

drivers/gpu/drm/i915/i915_gem_evict.c

+36 −9
Original line number Diff line number Diff line
@@ -46,6 +46,25 @@ mark_free(struct i915_vma *vma, struct list_head *unwind) 
	return drm_mm_scan_add_block(&vma->node);

}



/**

 * i915_gem_evict_something - Evict vmas to make room for binding a new one

 * @dev: drm_device

 * @vm: address space to evict from

 * @size: size of the desired free space

 * @alignment: alignment constraint of the desired free space

 * @cache_level: cache_level for the desired space

 * @mappable: whether the free space must be mappable

 * @nonblocking: whether evicting active objects is allowed or not

 *

 * This function will try to evict vmas until a free space satisfying the

 * requirements is found. Callers must check first whether any such hole exists

 * already before calling this function.

 *

 * This function is used by the object/vma binding code.

 *

 * To clarify: This is for freeing up virtual address space, not for freeing

 * memory in e.g. the shrinker.

 */

int

i915_gem_evict_something(struct drm_device *dev, struct i915_address_space *vm,

			 int min_size, unsigned alignment, unsigned cache_level,
@@ -177,19 +196,19 @@ i915_gem_evict_something(struct drm_device *dev, struct i915_address_space *vm, 
}



/**

 * i915_gem_evict_vm - Try to free up VM space

 * i915_gem_evict_vm - Evict all idle vmas from a vm

 *

 * @vm: Address space to evict from

 * @vm: Address space to cleanse

 * @do_idle: Boolean directing whether to idle first.

 *

 * VM eviction is about freeing up virtual address space. If one wants fine

 * grained eviction, they should see evict something for more details. In terms

 * of freeing up actual system memory, this function may not accomplish the

 * desired result. An object may be shared in multiple address space, and this

 * function will not assert those objects be freed.

 * This function evicts all idles vmas from a vm. If all unpinned vmas should be

 * evicted the @do_idle needs to be set to true.

 *

 * Using do_idle will result in a more complete eviction because it retires, and

 * inactivates current BOs.

 * This is used by the execbuf code as a last-ditch effort to defragment the

 * address space.

 *

 * To clarify: This is for freeing up virtual address space, not for freeing

 * memory in e.g. the shrinker.

 */

int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)

{
@@ -213,6 +232,14 @@ int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle) 
	return 0;

}



/**

 * i915_gem_evict_everything - Try to evict all objects

 * @dev: Device to evict objects for

 *

 * This functions tries to evict all gem objects from all address spaces. Used

 * by the shrinker as a last-ditch effort and for suspend, before releasing the

 * backing storage of all unbound objects.

 */

int

i915_gem_evict_everything(struct drm_device *dev)

{