On Mon, 2014-04-07 at 20:01 +0000, Rodrigo Vivi wrote:
> From: Chris Wilson <ch...@chris-wilson.co.uk>
>
> If we run out of stolen memory when trying to allocate an object, see if
> we can reap enough purgeable objects to free up enough contiguous free
> space for the allocation. This is in principle very much like evicting
> objects to free up enough contiguous space in the vma when binding
> a new object - and you will be forgiven for thinking that the code looks
> very similar.
>
> At the moment, we do not allow userspace to allocate objects in stolen,
> so there is neither the memory pressure to trigger stolen eviction nor
> any purgeable objects inside the stolen arena. However, this will change
> in the near future, and so better management and defragmentation of
> stolen memory will become a real issue.
>
> Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
> Cc: "Gupta, Sourab" <sourab.gu...@intel.com>
> Cc: "Goel, Akash" <akash.g...@intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.v...@gmail.com>
> ---
> drivers/gpu/drm/i915/i915_gem_stolen.c | 119
> ++++++++++++++++++++++++++++++---
> 1 file changed, 108 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c
> b/drivers/gpu/drm/i915/i915_gem_stolen.c
> index 62ef55b..1fc1986 100644
> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
> @@ -329,18 +329,25 @@ cleanup:
> return NULL;
> }
>
> -struct drm_i915_gem_object *
> -i915_gem_object_create_stolen(struct drm_device *dev, u32 size)
> +static bool mark_free(struct drm_i915_gem_object *obj, struct list_head
> *unwind)
> +{
> + if (obj->stolen == NULL)
> + return false;
> +
> + if (obj->madv != I915_MADV_DONTNEED)
> + return false;
> +
> + list_add(&obj->obj_exec_link, unwind);
> + return drm_mm_scan_add_block(obj->stolen);
> +}
> +
> +static struct drm_mm_node *stolen_alloc(struct drm_i915_private *dev_priv,
> u32 size)
> {
> - struct drm_i915_private *dev_priv = dev->dev_private;
> - struct drm_i915_gem_object *obj;
> struct drm_mm_node *stolen;
> + struct drm_i915_gem_object *obj;
> + struct list_head unwind, evict;
> int ret;
>
> - if (!drm_mm_initialized(&dev_priv->mm.stolen))
> - return NULL;
> -
> - DRM_DEBUG_KMS("creating stolen object: size=%x\n", size);
> if (size == 0)
> return NULL;
>
> @@ -350,11 +357,101 @@ i915_gem_object_create_stolen(struct drm_device *dev,
> u32 size)
>
> ret = drm_mm_insert_node(&dev_priv->mm.stolen, stolen, size,
> 4096, DRM_MM_SEARCH_DEFAULT);
> - if (ret) {
> - kfree(stolen);
> - return NULL;
> + if (ret == 0)
> + return stolen;
> +
> + /* No more stolen memory available, or too fragmented.
> + * Try evicting purgeable objects and search again.
> + */
> +
> + drm_mm_init_scan(&dev_priv->mm.stolen, size, 4096, 0);
> + INIT_LIST_HEAD(&unwind);
> +
> + list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list)
> + if (mark_free(obj, &unwind))
> + goto found;
> +
> + list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list)
> + if (mark_free(obj, &unwind))
> + goto found;
> +
> +found:
> + INIT_LIST_HEAD(&evict);
> + while (!list_empty(&unwind)) {
> + obj = list_first_entry(&unwind,
> + struct drm_i915_gem_object,
> + obj_exec_link);
> + list_del_init(&obj->obj_exec_link);
> +
> + if (drm_mm_scan_remove_block(obj->stolen)) {
> + list_add(&obj->obj_exec_link, &evict);
> + drm_gem_object_reference(&obj->base);
> + }
> }
>
> + ret = 0;
> + while (!list_empty(&evict)) {
> + obj = list_first_entry(&evict,
> + struct drm_i915_gem_object,
> + obj_exec_link);
> + list_del_init(&obj->obj_exec_link);
> +
> + if (ret == 0) {
> + struct i915_vma *vma, *vma_next;
> +
> + list_for_each_entry_safe(vma, vma_next,
> + &obj->vma_list,
> + vma_link)
> + if (i915_vma_unbind(vma))
> + break;
> +
> + /* Stolen pins its pages to prevent the
> + * normal shrinker from processing stolen
> + * objects.
> + */
> + i915_gem_object_unpin_pages(obj);
> +
> + ret = i915_gem_object_put_pages(obj);
> + if (ret == 0) {
> + obj->madv = __I915_MADV_PURGED;
> +
> + kfree(obj->stolen);
> + obj->stolen = NULL;
> + } else
> + i915_gem_object_pin_pages(obj);
> + }
> +
> + drm_gem_object_unreference(&obj->base);
> + }
> +
> + if (ret == 0)
> + ret = drm_mm_insert_node(&dev_priv->mm.stolen, stolen, size,
> + 4096, DRM_MM_SEARCH_DEFAULT);
> + if (ret == 0)
> + return stolen;
> +
> + kfree(stolen);
> + return NULL;
> +}
> +
> +struct drm_i915_gem_object *
> +i915_gem_object_create_stolen(struct drm_device *dev, u32 size)
> +{
> + struct drm_i915_private *dev_priv = dev->dev_private;
> + struct drm_i915_gem_object *obj;
> + struct drm_mm_node *stolen;
> +
> + lockdep_assert_held(&dev->struct_mutex);
> +
> + if (!drm_mm_initialized(&dev_priv->mm.stolen))
> + return NULL;
> +
> + DRM_DEBUG_KMS("creating stolen object: size=%x\n", size);
> +
> + stolen = stolen_alloc(dev_priv, size);
> + if (stolen == NULL)
> + return NULL;
> +
> obj = _i915_gem_object_create_stolen(dev, stolen);
> if (obj)
> return obj;
Hi Rodrigo,
In this patch, while freeing the purgeable stolen object, the memory
node also has to be freed, so as to make space for new object. We need
to call drm_mm_remove_node while freeing obj.
The below modification patch was floated earlier for this purpose:
http://lists.freedesktop.org/archives/intel-gfx/2014-March/041282.html
Regards,
Sourab
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