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25 #include <linux/oom.h>
26 #include <linux/shmem_fs.h>
27 #include <linux/slab.h>
28 #include <linux/swap.h>
29 #include <linux/pci.h>
30 #include <linux/dma-buf.h>
32 #include <drm/i915_drm.h>
35 #include "i915_trace.h"
37 static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
39 if (!mutex_is_locked(mutex))
42 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_MUTEXES)
43 return mutex->owner == task;
45 /* Since UP may be pre-empted, we cannot assume that we own the lock */
50 static int num_vma_bound(struct drm_i915_gem_object *obj)
55 list_for_each_entry(vma, &obj->vma_list, vma_link) {
56 if (drm_mm_node_allocated(&vma->node))
65 static bool swap_available(void)
67 return get_nr_swap_pages() > 0;
70 static bool can_release_pages(struct drm_i915_gem_object *obj)
72 /* Only report true if by unbinding the object and putting its pages
73 * we can actually make forward progress towards freeing physical
76 * If the pages are pinned for any other reason than being bound
77 * to the GPU, simply unbinding from the GPU is not going to succeed
78 * in releasing our pin count on the pages themselves.
80 if (obj->pages_pin_count != num_vma_bound(obj))
83 /* We can only return physical pages to the system if we can either
84 * discard the contents (because the user has marked them as being
85 * purgeable) or if we can move their contents out to swap.
87 return swap_available() || obj->madv == I915_MADV_DONTNEED;
91 * i915_gem_shrink - Shrink buffer object caches
92 * @dev_priv: i915 device
93 * @target: amount of memory to make available, in pages
94 * @flags: control flags for selecting cache types
96 * This function is the main interface to the shrinker. It will try to release
97 * up to @target pages of main memory backing storage from buffer objects.
98 * Selection of the specific caches can be done with @flags. This is e.g. useful
99 * when purgeable objects should be removed from caches preferentially.
101 * Note that it's not guaranteed that released amount is actually available as
102 * free system memory - the pages might still be in-used to due to other reasons
103 * (like cpu mmaps) or the mm core has reused them before we could grab them.
104 * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
105 * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
107 * Also note that any kind of pinning (both per-vma address space pins and
108 * backing storage pins at the buffer object level) result in the shrinker code
109 * having to skip the object.
112 * The number of pages of backing storage actually released.
115 i915_gem_shrink(struct drm_i915_private *dev_priv,
116 unsigned long target, unsigned flags)
119 struct list_head *list;
122 { &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
123 { &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
126 unsigned long count = 0;
128 trace_i915_gem_shrink(dev_priv, target, flags);
129 i915_gem_retire_requests(dev_priv->dev);
132 * As we may completely rewrite the (un)bound list whilst unbinding
133 * (due to retiring requests) we have to strictly process only
134 * one element of the list at the time, and recheck the list
135 * on every iteration.
137 * In particular, we must hold a reference whilst removing the
138 * object as we may end up waiting for and/or retiring the objects.
139 * This might release the final reference (held by the active list)
140 * and result in the object being freed from under us. This is
141 * similar to the precautions the eviction code must take whilst
144 * Also note that although these lists do not hold a reference to
145 * the object we can safely grab one here: The final object
146 * unreferencing and the bound_list are both protected by the
147 * dev->struct_mutex and so we won't ever be able to observe an
148 * object on the bound_list with a reference count equals 0.
150 for (phase = phases; phase->list; phase++) {
151 struct list_head still_in_list;
153 if ((flags & phase->bit) == 0)
156 INIT_LIST_HEAD(&still_in_list);
157 while (count < target && !list_empty(phase->list)) {
158 struct drm_i915_gem_object *obj;
159 struct i915_vma *vma, *v;
161 obj = list_first_entry(phase->list,
162 typeof(*obj), global_list);
163 list_move_tail(&obj->global_list, &still_in_list);
165 if (flags & I915_SHRINK_PURGEABLE &&
166 obj->madv != I915_MADV_DONTNEED)
169 if ((flags & I915_SHRINK_ACTIVE) == 0 && obj->active)
172 if (!can_release_pages(obj))
175 drm_gem_object_reference(&obj->base);
177 /* For the unbound phase, this should be a no-op! */
178 list_for_each_entry_safe(vma, v,
179 &obj->vma_list, vma_link)
180 if (i915_vma_unbind(vma))
183 if (i915_gem_object_put_pages(obj) == 0)
184 count += obj->base.size >> PAGE_SHIFT;
186 drm_gem_object_unreference(&obj->base);
188 list_splice(&still_in_list, phase->list);
191 i915_gem_retire_requests(dev_priv->dev);
197 * i915_gem_shrink_all - Shrink buffer object caches completely
198 * @dev_priv: i915 device
200 * This is a simple wraper around i915_gem_shrink() to aggressively shrink all
201 * caches completely. It also first waits for and retires all outstanding
202 * requests to also be able to release backing storage for active objects.
204 * This should only be used in code to intentionally quiescent the gpu or as a
205 * last-ditch effort when memory seems to have run out.
208 * The number of pages of backing storage actually released.
210 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
212 return i915_gem_shrink(dev_priv, -1UL,
214 I915_SHRINK_UNBOUND |
218 static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
220 if (!mutex_trylock(&dev->struct_mutex)) {
221 if (!mutex_is_locked_by(&dev->struct_mutex, current))
224 if (to_i915(dev)->mm.shrinker_no_lock_stealing)
235 i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
237 struct drm_i915_private *dev_priv =
238 container_of(shrinker, struct drm_i915_private, mm.shrinker);
239 struct drm_device *dev = dev_priv->dev;
240 struct drm_i915_gem_object *obj;
244 if (!i915_gem_shrinker_lock(dev, &unlock))
248 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list)
249 if (obj->pages_pin_count == 0)
250 count += obj->base.size >> PAGE_SHIFT;
252 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
253 if (!obj->active && can_release_pages(obj))
254 count += obj->base.size >> PAGE_SHIFT;
258 mutex_unlock(&dev->struct_mutex);
264 i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
266 struct drm_i915_private *dev_priv =
267 container_of(shrinker, struct drm_i915_private, mm.shrinker);
268 struct drm_device *dev = dev_priv->dev;
272 if (!i915_gem_shrinker_lock(dev, &unlock))
275 freed = i915_gem_shrink(dev_priv,
278 I915_SHRINK_UNBOUND |
279 I915_SHRINK_PURGEABLE);
280 if (freed < sc->nr_to_scan)
281 freed += i915_gem_shrink(dev_priv,
282 sc->nr_to_scan - freed,
284 I915_SHRINK_UNBOUND);
286 mutex_unlock(&dev->struct_mutex);
292 i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
294 struct drm_i915_private *dev_priv =
295 container_of(nb, struct drm_i915_private, mm.oom_notifier);
296 struct drm_device *dev = dev_priv->dev;
297 struct drm_i915_gem_object *obj;
298 unsigned long timeout = msecs_to_jiffies(5000) + 1;
299 unsigned long pinned, bound, unbound, freed_pages;
300 bool was_interruptible;
303 while (!i915_gem_shrinker_lock(dev, &unlock) && --timeout) {
304 schedule_timeout_killable(1);
305 if (fatal_signal_pending(current))
309 pr_err("Unable to purge GPU memory due lock contention.\n");
313 was_interruptible = dev_priv->mm.interruptible;
314 dev_priv->mm.interruptible = false;
316 freed_pages = i915_gem_shrink_all(dev_priv);
318 dev_priv->mm.interruptible = was_interruptible;
320 /* Because we may be allocating inside our own driver, we cannot
321 * assert that there are no objects with pinned pages that are not
322 * being pointed to by hardware.
324 unbound = bound = pinned = 0;
325 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list) {
326 if (!obj->base.filp) /* not backed by a freeable object */
329 if (obj->pages_pin_count)
330 pinned += obj->base.size;
332 unbound += obj->base.size;
334 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
338 if (obj->pages_pin_count)
339 pinned += obj->base.size;
341 bound += obj->base.size;
345 mutex_unlock(&dev->struct_mutex);
347 if (freed_pages || unbound || bound)
348 pr_info("Purging GPU memory, %lu bytes freed, %lu bytes still pinned.\n",
349 freed_pages << PAGE_SHIFT, pinned);
350 if (unbound || bound)
351 pr_err("%lu and %lu bytes still available in the "
352 "bound and unbound GPU page lists.\n",
355 *(unsigned long *)ptr += freed_pages;
360 * i915_gem_shrinker_init - Initialize i915 shrinker
361 * @dev_priv: i915 device
363 * This function registers and sets up the i915 shrinker and OOM handler.
365 void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
367 dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
368 dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count;
369 dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS;
370 register_shrinker(&dev_priv->mm.shrinker);
372 dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
373 register_oom_notifier(&dev_priv->mm.oom_notifier);