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![Chris Wilson](/assets/img/avatar_default.png)
When looking for viable candidates to shrink, we only want objects that are not pinned. However to do so we performed a double iteration over the vma in the objects, first looking for the pin-count, then looking for allocations. We can do both at once and be slightly more explicit in our validity test. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
337 lines
10 KiB
C
337 lines
10 KiB
C
/*
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* Copyright © 2008-2015 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#include <linux/oom.h>
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#include <linux/shmem_fs.h>
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#include <linux/slab.h>
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#include <linux/swap.h>
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#include <linux/pci.h>
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#include <linux/dma-buf.h>
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#include <drm/drmP.h>
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#include <drm/i915_drm.h>
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#include "i915_drv.h"
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#include "i915_trace.h"
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static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
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{
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if (!mutex_is_locked(mutex))
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return false;
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#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_MUTEXES)
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return mutex->owner == task;
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#else
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/* Since UP may be pre-empted, we cannot assume that we own the lock */
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return false;
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#endif
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}
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/**
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* i915_gem_shrink - Shrink buffer object caches
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* @dev_priv: i915 device
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* @target: amount of memory to make available, in pages
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* @flags: control flags for selecting cache types
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*
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* This function is the main interface to the shrinker. It will try to release
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* up to @target pages of main memory backing storage from buffer objects.
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* Selection of the specific caches can be done with @flags. This is e.g. useful
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* when purgeable objects should be removed from caches preferentially.
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*
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* Note that it's not guaranteed that released amount is actually available as
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* free system memory - the pages might still be in-used to due to other reasons
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* (like cpu mmaps) or the mm core has reused them before we could grab them.
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* Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
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* avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
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*
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* Also note that any kind of pinning (both per-vma address space pins and
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* backing storage pins at the buffer object level) result in the shrinker code
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* having to skip the object.
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*
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* Returns:
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* The number of pages of backing storage actually released.
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*/
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unsigned long
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i915_gem_shrink(struct drm_i915_private *dev_priv,
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long target, unsigned flags)
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{
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const struct {
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struct list_head *list;
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unsigned int bit;
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} phases[] = {
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{ &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
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{ &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
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{ NULL, 0 },
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}, *phase;
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unsigned long count = 0;
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/*
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* As we may completely rewrite the (un)bound list whilst unbinding
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* (due to retiring requests) we have to strictly process only
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* one element of the list at the time, and recheck the list
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* on every iteration.
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*
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* In particular, we must hold a reference whilst removing the
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* object as we may end up waiting for and/or retiring the objects.
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* This might release the final reference (held by the active list)
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* and result in the object being freed from under us. This is
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* similar to the precautions the eviction code must take whilst
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* removing objects.
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*
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* Also note that although these lists do not hold a reference to
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* the object we can safely grab one here: The final object
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* unreferencing and the bound_list are both protected by the
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* dev->struct_mutex and so we won't ever be able to observe an
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* object on the bound_list with a reference count equals 0.
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*/
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for (phase = phases; phase->list; phase++) {
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struct list_head still_in_list;
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if ((flags & phase->bit) == 0)
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continue;
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INIT_LIST_HEAD(&still_in_list);
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while (count < target && !list_empty(phase->list)) {
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struct drm_i915_gem_object *obj;
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struct i915_vma *vma, *v;
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obj = list_first_entry(phase->list,
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typeof(*obj), global_list);
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list_move_tail(&obj->global_list, &still_in_list);
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if (flags & I915_SHRINK_PURGEABLE &&
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obj->madv != I915_MADV_DONTNEED)
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continue;
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drm_gem_object_reference(&obj->base);
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/* For the unbound phase, this should be a no-op! */
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list_for_each_entry_safe(vma, v,
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&obj->vma_list, vma_link)
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if (i915_vma_unbind(vma))
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break;
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if (i915_gem_object_put_pages(obj) == 0)
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count += obj->base.size >> PAGE_SHIFT;
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drm_gem_object_unreference(&obj->base);
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}
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list_splice(&still_in_list, phase->list);
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}
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return count;
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}
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/**
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* i915_gem_shrink - Shrink buffer object caches completely
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* @dev_priv: i915 device
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*
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* This is a simple wraper around i915_gem_shrink() to aggressively shrink all
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* caches completely. It also first waits for and retires all outstanding
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* requests to also be able to release backing storage for active objects.
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*
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* This should only be used in code to intentionally quiescent the gpu or as a
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* last-ditch effort when memory seems to have run out.
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*
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* Returns:
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* The number of pages of backing storage actually released.
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*/
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unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
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{
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i915_gem_evict_everything(dev_priv->dev);
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return i915_gem_shrink(dev_priv, LONG_MAX,
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I915_SHRINK_BOUND | I915_SHRINK_UNBOUND);
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}
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static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
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{
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if (!mutex_trylock(&dev->struct_mutex)) {
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if (!mutex_is_locked_by(&dev->struct_mutex, current))
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return false;
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if (to_i915(dev)->mm.shrinker_no_lock_stealing)
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return false;
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*unlock = false;
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} else
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*unlock = true;
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return true;
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}
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static int num_vma_bound(struct drm_i915_gem_object *obj)
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{
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struct i915_vma *vma;
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int count = 0;
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list_for_each_entry(vma, &obj->vma_list, vma_link) {
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if (drm_mm_node_allocated(&vma->node))
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count++;
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if (vma->pin_count)
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count++;
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}
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return count;
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}
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static unsigned long
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i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
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{
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struct drm_i915_private *dev_priv =
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container_of(shrinker, struct drm_i915_private, mm.shrinker);
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struct drm_device *dev = dev_priv->dev;
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struct drm_i915_gem_object *obj;
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unsigned long count;
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bool unlock;
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if (!i915_gem_shrinker_lock(dev, &unlock))
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return 0;
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count = 0;
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list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list)
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if (obj->pages_pin_count == 0)
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count += obj->base.size >> PAGE_SHIFT;
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list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
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if (obj->pages_pin_count == num_vma_bound(obj))
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count += obj->base.size >> PAGE_SHIFT;
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}
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if (unlock)
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mutex_unlock(&dev->struct_mutex);
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return count;
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}
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static unsigned long
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i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
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{
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struct drm_i915_private *dev_priv =
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container_of(shrinker, struct drm_i915_private, mm.shrinker);
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struct drm_device *dev = dev_priv->dev;
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unsigned long freed;
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bool unlock;
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if (!i915_gem_shrinker_lock(dev, &unlock))
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return SHRINK_STOP;
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freed = i915_gem_shrink(dev_priv,
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sc->nr_to_scan,
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I915_SHRINK_BOUND |
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I915_SHRINK_UNBOUND |
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I915_SHRINK_PURGEABLE);
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if (freed < sc->nr_to_scan)
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freed += i915_gem_shrink(dev_priv,
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sc->nr_to_scan - freed,
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I915_SHRINK_BOUND |
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I915_SHRINK_UNBOUND);
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if (unlock)
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mutex_unlock(&dev->struct_mutex);
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return freed;
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}
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static int
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i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
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{
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struct drm_i915_private *dev_priv =
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container_of(nb, struct drm_i915_private, mm.oom_notifier);
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struct drm_device *dev = dev_priv->dev;
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struct drm_i915_gem_object *obj;
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unsigned long timeout = msecs_to_jiffies(5000) + 1;
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unsigned long pinned, bound, unbound, freed_pages;
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bool was_interruptible;
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bool unlock;
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while (!i915_gem_shrinker_lock(dev, &unlock) && --timeout) {
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schedule_timeout_killable(1);
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if (fatal_signal_pending(current))
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return NOTIFY_DONE;
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}
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if (timeout == 0) {
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pr_err("Unable to purge GPU memory due lock contention.\n");
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return NOTIFY_DONE;
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}
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was_interruptible = dev_priv->mm.interruptible;
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dev_priv->mm.interruptible = false;
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freed_pages = i915_gem_shrink_all(dev_priv);
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dev_priv->mm.interruptible = was_interruptible;
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/* Because we may be allocating inside our own driver, we cannot
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* assert that there are no objects with pinned pages that are not
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* being pointed to by hardware.
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*/
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unbound = bound = pinned = 0;
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list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list) {
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if (!obj->base.filp) /* not backed by a freeable object */
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continue;
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if (obj->pages_pin_count)
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pinned += obj->base.size;
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else
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unbound += obj->base.size;
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}
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list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
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if (!obj->base.filp)
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continue;
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if (obj->pages_pin_count)
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pinned += obj->base.size;
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else
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bound += obj->base.size;
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}
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if (unlock)
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mutex_unlock(&dev->struct_mutex);
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if (freed_pages || unbound || bound)
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pr_info("Purging GPU memory, %lu bytes freed, %lu bytes still pinned.\n",
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freed_pages << PAGE_SHIFT, pinned);
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if (unbound || bound)
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pr_err("%lu and %lu bytes still available in the "
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"bound and unbound GPU page lists.\n",
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bound, unbound);
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*(unsigned long *)ptr += freed_pages;
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return NOTIFY_DONE;
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}
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/**
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* i915_gem_shrinker_init - Initialize i915 shrinker
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* @dev_priv: i915 device
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*
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* This function registers and sets up the i915 shrinker and OOM handler.
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*/
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void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
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{
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dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
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dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count;
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dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS;
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register_shrinker(&dev_priv->mm.shrinker);
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dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
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register_oom_notifier(&dev_priv->mm.oom_notifier);
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}
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