From c2c1d4912cd7028384d7f25d2faefefb8958f64d Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 29 Jan 2014 22:07:11 +0100 Subject: [PATCH] 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 Acked-by: Ben Widawsky Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_gem_evict.c | 45 ++++++++++++++++++++++++++++------- 1 file changed, 36 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c index 50e7e3a..5168d6a 100644 --- a/drivers/gpu/drm/i915/i915_gem_evict.c +++ b/drivers/gpu/drm/i915/i915_gem_evict.c @@ -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 @@ found: } /** - * 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) { -- 2.7.4