2 * Copyright © 2008-2015 Intel Corporation
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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>
31 #include <linux/vmalloc.h>
33 #include <drm/i915_drm.h>
36 #include "i915_trace.h"
38 static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
40 if (!mutex_is_locked(mutex))
43 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_MUTEXES)
44 return mutex->owner == task;
46 /* Since UP may be pre-empted, we cannot assume that we own the lock */
51 static int num_vma_bound(struct drm_i915_gem_object *obj)
56 list_for_each_entry(vma, &obj->vma_list, obj_link) {
57 if (drm_mm_node_allocated(&vma->node))
66 static bool swap_available(void)
68 return get_nr_swap_pages() > 0;
71 static bool can_release_pages(struct drm_i915_gem_object *obj)
73 /* Only report true if by unbinding the object and putting its pages
74 * we can actually make forward progress towards freeing physical
77 * If the pages are pinned for any other reason than being bound
78 * to the GPU, simply unbinding from the GPU is not going to succeed
79 * in releasing our pin count on the pages themselves.
81 if (obj->pages_pin_count != num_vma_bound(obj))
84 /* We can only return physical pages to the system if we can either
85 * discard the contents (because the user has marked them as being
86 * purgeable) or if we can move their contents out to swap.
88 return swap_available() || obj->madv == I915_MADV_DONTNEED;
92 * i915_gem_shrink - Shrink buffer object caches
93 * @dev_priv: i915 device
94 * @target: amount of memory to make available, in pages
95 * @flags: control flags for selecting cache types
97 * This function is the main interface to the shrinker. It will try to release
98 * up to @target pages of main memory backing storage from buffer objects.
99 * Selection of the specific caches can be done with @flags. This is e.g. useful
100 * when purgeable objects should be removed from caches preferentially.
102 * Note that it's not guaranteed that released amount is actually available as
103 * free system memory - the pages might still be in-used to due to other reasons
104 * (like cpu mmaps) or the mm core has reused them before we could grab them.
105 * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
106 * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
108 * Also note that any kind of pinning (both per-vma address space pins and
109 * backing storage pins at the buffer object level) result in the shrinker code
110 * having to skip the object.
113 * The number of pages of backing storage actually released.
116 i915_gem_shrink(struct drm_i915_private *dev_priv,
117 unsigned long target, unsigned flags)
120 struct list_head *list;
123 { &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
124 { &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
127 unsigned long count = 0;
129 trace_i915_gem_shrink(dev_priv, target, flags);
130 i915_gem_retire_requests(dev_priv->dev);
133 * As we may completely rewrite the (un)bound list whilst unbinding
134 * (due to retiring requests) we have to strictly process only
135 * one element of the list at the time, and recheck the list
136 * on every iteration.
138 * In particular, we must hold a reference whilst removing the
139 * object as we may end up waiting for and/or retiring the objects.
140 * This might release the final reference (held by the active list)
141 * and result in the object being freed from under us. This is
142 * similar to the precautions the eviction code must take whilst
145 * Also note that although these lists do not hold a reference to
146 * the object we can safely grab one here: The final object
147 * unreferencing and the bound_list are both protected by the
148 * dev->struct_mutex and so we won't ever be able to observe an
149 * object on the bound_list with a reference count equals 0.
151 for (phase = phases; phase->list; phase++) {
152 struct list_head still_in_list;
154 if ((flags & phase->bit) == 0)
157 INIT_LIST_HEAD(&still_in_list);
158 while (count < target && !list_empty(phase->list)) {
159 struct drm_i915_gem_object *obj;
160 struct i915_vma *vma, *v;
162 obj = list_first_entry(phase->list,
163 typeof(*obj), global_list);
164 list_move_tail(&obj->global_list, &still_in_list);
166 if (flags & I915_SHRINK_PURGEABLE &&
167 obj->madv != I915_MADV_DONTNEED)
170 if (flags & I915_SHRINK_VMAPS &&
171 !is_vmalloc_addr(obj->mapping))
174 if ((flags & I915_SHRINK_ACTIVE) == 0 && obj->active)
177 if (!can_release_pages(obj))
180 drm_gem_object_reference(&obj->base);
182 /* For the unbound phase, this should be a no-op! */
183 list_for_each_entry_safe(vma, v,
184 &obj->vma_list, obj_link)
185 if (i915_vma_unbind(vma))
188 if (i915_gem_object_put_pages(obj) == 0)
189 count += obj->base.size >> PAGE_SHIFT;
191 drm_gem_object_unreference(&obj->base);
193 list_splice(&still_in_list, phase->list);
196 i915_gem_retire_requests(dev_priv->dev);
202 * i915_gem_shrink_all - Shrink buffer object caches completely
203 * @dev_priv: i915 device
205 * This is a simple wraper around i915_gem_shrink() to aggressively shrink all
206 * caches completely. It also first waits for and retires all outstanding
207 * requests to also be able to release backing storage for active objects.
209 * This should only be used in code to intentionally quiescent the gpu or as a
210 * last-ditch effort when memory seems to have run out.
213 * The number of pages of backing storage actually released.
215 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
217 return i915_gem_shrink(dev_priv, -1UL,
219 I915_SHRINK_UNBOUND |
223 static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
225 if (!mutex_trylock(&dev->struct_mutex)) {
226 if (!mutex_is_locked_by(&dev->struct_mutex, current))
229 if (to_i915(dev)->mm.shrinker_no_lock_stealing)
240 i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
242 struct drm_i915_private *dev_priv =
243 container_of(shrinker, struct drm_i915_private, mm.shrinker);
244 struct drm_device *dev = dev_priv->dev;
245 struct drm_i915_gem_object *obj;
249 if (!i915_gem_shrinker_lock(dev, &unlock))
253 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list)
254 if (can_release_pages(obj))
255 count += obj->base.size >> PAGE_SHIFT;
257 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
258 if (!obj->active && can_release_pages(obj))
259 count += obj->base.size >> PAGE_SHIFT;
263 mutex_unlock(&dev->struct_mutex);
269 i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
271 struct drm_i915_private *dev_priv =
272 container_of(shrinker, struct drm_i915_private, mm.shrinker);
273 struct drm_device *dev = dev_priv->dev;
277 if (!i915_gem_shrinker_lock(dev, &unlock))
280 freed = i915_gem_shrink(dev_priv,
283 I915_SHRINK_UNBOUND |
284 I915_SHRINK_PURGEABLE);
285 if (freed < sc->nr_to_scan)
286 freed += i915_gem_shrink(dev_priv,
287 sc->nr_to_scan - freed,
289 I915_SHRINK_UNBOUND);
291 mutex_unlock(&dev->struct_mutex);
296 struct shrinker_lock_uninterruptible {
297 bool was_interruptible;
302 i915_gem_shrinker_lock_uninterruptible(struct drm_i915_private *dev_priv,
303 struct shrinker_lock_uninterruptible *slu,
306 unsigned long timeout = msecs_to_jiffies(timeout_ms) + 1;
308 while (!i915_gem_shrinker_lock(dev_priv->dev, &slu->unlock)) {
309 schedule_timeout_killable(1);
310 if (fatal_signal_pending(current))
312 if (--timeout == 0) {
313 pr_err("Unable to lock GPU to purge memory.\n");
318 slu->was_interruptible = dev_priv->mm.interruptible;
319 dev_priv->mm.interruptible = false;
324 i915_gem_shrinker_unlock_uninterruptible(struct drm_i915_private *dev_priv,
325 struct shrinker_lock_uninterruptible *slu)
327 dev_priv->mm.interruptible = slu->was_interruptible;
329 mutex_unlock(&dev_priv->dev->struct_mutex);
333 i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
335 struct drm_i915_private *dev_priv =
336 container_of(nb, struct drm_i915_private, mm.oom_notifier);
337 struct shrinker_lock_uninterruptible slu;
338 struct drm_i915_gem_object *obj;
339 unsigned long pinned, bound, unbound, freed_pages;
341 if (!i915_gem_shrinker_lock_uninterruptible(dev_priv, &slu, 5000))
344 freed_pages = i915_gem_shrink_all(dev_priv);
346 /* Because we may be allocating inside our own driver, we cannot
347 * assert that there are no objects with pinned pages that are not
348 * being pointed to by hardware.
350 unbound = bound = pinned = 0;
351 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list) {
352 if (!obj->base.filp) /* not backed by a freeable object */
355 if (obj->pages_pin_count)
356 pinned += obj->base.size;
358 unbound += obj->base.size;
360 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
364 if (obj->pages_pin_count > num_vma_bound(obj))
365 pinned += obj->base.size;
367 bound += obj->base.size;
370 i915_gem_shrinker_unlock_uninterruptible(dev_priv, &slu);
372 if (freed_pages || unbound || bound)
373 pr_info("Purging GPU memory, %lu bytes freed, %lu bytes still pinned.\n",
374 freed_pages << PAGE_SHIFT, pinned);
375 if (unbound || bound)
376 pr_err("%lu and %lu bytes still available in the "
377 "bound and unbound GPU page lists.\n",
380 *(unsigned long *)ptr += freed_pages;
385 i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
387 struct drm_i915_private *dev_priv =
388 container_of(nb, struct drm_i915_private, mm.vmap_notifier);
389 struct shrinker_lock_uninterruptible slu;
390 unsigned long freed_pages;
392 if (!i915_gem_shrinker_lock_uninterruptible(dev_priv, &slu, 5000))
395 freed_pages = i915_gem_shrink(dev_priv, -1UL,
397 I915_SHRINK_UNBOUND |
401 i915_gem_shrinker_unlock_uninterruptible(dev_priv, &slu);
403 *(unsigned long *)ptr += freed_pages;
408 * i915_gem_shrinker_init - Initialize i915 shrinker
409 * @dev_priv: i915 device
411 * This function registers and sets up the i915 shrinker and OOM handler.
413 void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
415 dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
416 dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count;
417 dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS;
418 WARN_ON(register_shrinker(&dev_priv->mm.shrinker));
420 dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
421 WARN_ON(register_oom_notifier(&dev_priv->mm.oom_notifier));
423 dev_priv->mm.vmap_notifier.notifier_call = i915_gem_shrinker_vmap;
424 WARN_ON(register_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
428 * i915_gem_shrinker_cleanup - Clean up i915 shrinker
429 * @dev_priv: i915 device
431 * This function unregisters the i915 shrinker and OOM handler.
433 void i915_gem_shrinker_cleanup(struct drm_i915_private *dev_priv)
435 WARN_ON(unregister_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
436 WARN_ON(unregister_oom_notifier(&dev_priv->mm.oom_notifier));
437 unregister_shrinker(&dev_priv->mm.shrinker);