static void cancel_userptr(struct work_struct *work)
{
struct i915_mmu_object *mo = container_of(work, typeof(*mo), work);
struct drm_i915_gem_object *obj = mo->obj;
struct work_struct *active;
/* Cancel any active worker and force us to re-evaluate gup */
mutex_lock(&obj->mm.lock);
active = fetch_and_zero(&obj->userptr.work);
mutex_unlock(&obj->mm.lock);
if (active)
goto out;
i915_gem_object_wait(obj, I915_WAIT_ALL, MAX_SCHEDULE_TIMEOUT, NULL);
mutex_lock(&obj->base.dev->struct_mutex);
/* We are inside a kthread context and can't be interrupted */
if (i915_gem_object_unbind(obj) == 0)
__i915_gem_object_put_pages(obj, I915_MM_NORMAL);
WARN_ONCE(i915_gem_object_has_pages(obj),
"Failed to release pages: bind_count=%d, pages_pin_count=%d, pin_global=%d\n",
obj->bind_count,
atomic_read(&obj->mm.pages_pin_count),
obj->pin_global);
mutex_unlock(&obj->base.dev->struct_mutex);
out:
i915_gem_object_put(obj);
}
/**
* i915_gem_shrink - Shrink buffer object caches
* @dev_priv: i915 device
* @target: amount of memory to make available, in pages
* @nr_scanned: optional output for number of pages scanned (incremental)
* @flags: control flags for selecting cache types
*
* This function is the main interface to the shrinker. It will try to release
* up to @target pages of main memory backing storage from buffer objects.
* Selection of the specific caches can be done with @flags. This is e.g. useful
* when purgeable objects should be removed from caches preferentially.
*
* Note that it's not guaranteed that released amount is actually available as
* free system memory - the pages might still be in-used to due to other reasons
* (like cpu mmaps) or the mm core has reused them before we could grab them.
* Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
* avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
*
* Also note that any kind of pinning (both per-vma address space pins and
* backing storage pins at the buffer object level) result in the shrinker code
* having to skip the object.
*
* Returns:
* The number of pages of backing storage actually released.
*/
unsigned long
i915_gem_shrink(struct drm_i915_private *dev_priv,
unsigned long target,
unsigned long *nr_scanned,
unsigned flags)
{
const struct {
struct list_head *list;
unsigned int bit;
} phases[] = {
{ &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
{ &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
{ NULL, 0 },
}, *phase;
unsigned long count = 0;
unsigned long scanned = 0;
bool unlock;
if (!shrinker_lock(dev_priv, &unlock))
return 0;
/*
* When shrinking the active list, also consider active contexts.
* Active contexts are pinned until they are retired, and so can
* not be simply unbound to retire and unpin their pages. To shrink
* the contexts, we must wait until the gpu is idle.
*
* We don't care about errors here; if we cannot wait upon the GPU,
* we will free as much as we can and hope to get a second chance.
*/
if (flags & I915_SHRINK_ACTIVE)
i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED);
trace_i915_gem_shrink(dev_priv, target, flags);
i915_gem_retire_requests(dev_priv);
/*
* Unbinding of objects will require HW access; Let us not wake the
* device just to recover a little memory. If absolutely necessary,
* we will force the wake during oom-notifier.
*/
if ((flags & I915_SHRINK_BOUND) &&
!intel_runtime_pm_get_if_in_use(dev_priv))
flags &= ~I915_SHRINK_BOUND;
/*
* As we may completely rewrite the (un)bound list whilst unbinding
* (due to retiring requests) we have to strictly process only
* one element of the list at the time, and recheck the list
* on every iteration.
*
* In particular, we must hold a reference whilst removing the
* object as we may end up waiting for and/or retiring the objects.
* This might release the final reference (held by the active list)
* and result in the object being freed from under us. This is
* similar to the precautions the eviction code must take whilst
* removing objects.
*
* Also note that although these lists do not hold a reference to
* the object we can safely grab one here: The final object
* unreferencing and the bound_list are both protected by the
* dev->struct_mutex and so we won't ever be able to observe an
* object on the bound_list with a reference count equals 0.
*/
for (phase = phases; phase->list; phase++) {
struct list_head still_in_list;
struct drm_i915_gem_object *obj;
if ((flags & phase->bit) == 0)
continue;
INIT_LIST_HEAD(&still_in_list);
/*
* We serialize our access to unreferenced objects through
* the use of the struct_mutex. While the objects are not
* yet freed (due to RCU then a workqueue) we still want
* to be able to shrink their pages, so they remain on
* the unbound/bound list until actually freed.
*/
spin_lock(&dev_priv->mm.obj_lock);
while (count < target &&
(obj = list_first_entry_or_null(phase->list,
typeof(*obj),
mm.link))) {
list_move_tail(&obj->mm.link, &still_in_list);
if (flags & I915_SHRINK_PURGEABLE &&
obj->mm.madv != I915_MADV_DONTNEED)
continue;
if (flags & I915_SHRINK_VMAPS &&
!is_vmalloc_addr(obj->mm.mapping))
continue;
if (!(flags & I915_SHRINK_ACTIVE) &&
(i915_gem_object_is_active(obj) ||
i915_gem_object_is_framebuffer(obj)))
continue;
if (!can_release_pages(obj))
continue;
spin_unlock(&dev_priv->mm.obj_lock);
if (unsafe_drop_pages(obj)) {
/* May arrive from get_pages on another bo */
mutex_lock_nested(&obj->mm.lock,
I915_MM_SHRINKER);
if (!i915_gem_object_has_pages(obj)) {
__i915_gem_object_invalidate(obj);
count += obj->base.size >> PAGE_SHIFT;
}
mutex_unlock(&obj->mm.lock);
}
scanned += obj->base.size >> PAGE_SHIFT;
spin_lock(&dev_priv->mm.obj_lock);
}
list_splice_tail(&still_in_list, phase->list);
spin_unlock(&dev_priv->mm.obj_lock);
}
static bool unsafe_drop_pages(struct drm_i915_gem_object *obj)
{
if (i915_gem_object_unbind(obj) == 0)
__i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
return !i915_gem_object_has_pages(obj);
}
static void __i915_do_clflush(struct drm_i915_gem_object *obj)
{
GEM_BUG_ON(!i915_gem_object_has_pages(obj));
drm_clflush_sg(obj->mm.pages);
intel_fb_obj_flush(obj, ORIGIN_CPU);
}
