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 i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
40 switch (mutex_trylock_recursive(&dev->struct_mutex)) {
41 case MUTEX_TRYLOCK_FAILED:
44 case MUTEX_TRYLOCK_SUCCESS:
48 case MUTEX_TRYLOCK_RECURSIVE:
56 static void i915_gem_shrinker_unlock(struct drm_device *dev, bool unlock)
61 mutex_unlock(&dev->struct_mutex);
63 /* expedite the RCU grace period to free some request slabs */
64 synchronize_rcu_expedited();
67 static bool any_vma_pinned(struct drm_i915_gem_object *obj)
71 list_for_each_entry(vma, &obj->vma_list, obj_link)
72 if (i915_vma_is_pinned(vma))
78 static bool swap_available(void)
80 return get_nr_swap_pages() > 0;
83 static bool can_release_pages(struct drm_i915_gem_object *obj)
88 /* Consider only shrinkable ojects. */
89 if (!i915_gem_object_is_shrinkable(obj))
92 /* Only report true if by unbinding the object and putting its pages
93 * we can actually make forward progress towards freeing physical
96 * If the pages are pinned for any other reason than being bound
97 * to the GPU, simply unbinding from the GPU is not going to succeed
98 * in releasing our pin count on the pages themselves.
100 if (atomic_read(&obj->mm.pages_pin_count) > obj->bind_count)
103 if (any_vma_pinned(obj))
106 /* We can only return physical pages to the system if we can either
107 * discard the contents (because the user has marked them as being
108 * purgeable) or if we can move their contents out to swap.
110 return swap_available() || obj->mm.madv == I915_MADV_DONTNEED;
113 static bool unsafe_drop_pages(struct drm_i915_gem_object *obj)
115 if (i915_gem_object_unbind(obj) == 0)
116 __i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
117 return !READ_ONCE(obj->mm.pages);
121 * i915_gem_shrink - Shrink buffer object caches
122 * @dev_priv: i915 device
123 * @target: amount of memory to make available, in pages
124 * @flags: control flags for selecting cache types
126 * This function is the main interface to the shrinker. It will try to release
127 * up to @target pages of main memory backing storage from buffer objects.
128 * Selection of the specific caches can be done with @flags. This is e.g. useful
129 * when purgeable objects should be removed from caches preferentially.
131 * Note that it's not guaranteed that released amount is actually available as
132 * free system memory - the pages might still be in-used to due to other reasons
133 * (like cpu mmaps) or the mm core has reused them before we could grab them.
134 * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
135 * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
137 * Also note that any kind of pinning (both per-vma address space pins and
138 * backing storage pins at the buffer object level) result in the shrinker code
139 * having to skip the object.
142 * The number of pages of backing storage actually released.
145 i915_gem_shrink(struct drm_i915_private *dev_priv,
146 unsigned long target, unsigned flags)
149 struct list_head *list;
152 { &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
153 { &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
156 unsigned long count = 0;
159 if (!i915_gem_shrinker_lock(&dev_priv->drm, &unlock))
162 trace_i915_gem_shrink(dev_priv, target, flags);
163 i915_gem_retire_requests(dev_priv);
166 * Unbinding of objects will require HW access; Let us not wake the
167 * device just to recover a little memory. If absolutely necessary,
168 * we will force the wake during oom-notifier.
170 if ((flags & I915_SHRINK_BOUND) &&
171 !intel_runtime_pm_get_if_in_use(dev_priv))
172 flags &= ~I915_SHRINK_BOUND;
175 * As we may completely rewrite the (un)bound list whilst unbinding
176 * (due to retiring requests) we have to strictly process only
177 * one element of the list at the time, and recheck the list
178 * on every iteration.
180 * In particular, we must hold a reference whilst removing the
181 * object as we may end up waiting for and/or retiring the objects.
182 * This might release the final reference (held by the active list)
183 * and result in the object being freed from under us. This is
184 * similar to the precautions the eviction code must take whilst
187 * Also note that although these lists do not hold a reference to
188 * the object we can safely grab one here: The final object
189 * unreferencing and the bound_list are both protected by the
190 * dev->struct_mutex and so we won't ever be able to observe an
191 * object on the bound_list with a reference count equals 0.
193 for (phase = phases; phase->list; phase++) {
194 struct list_head still_in_list;
195 struct drm_i915_gem_object *obj;
197 if ((flags & phase->bit) == 0)
200 INIT_LIST_HEAD(&still_in_list);
201 while (count < target &&
202 (obj = list_first_entry_or_null(phase->list,
205 list_move_tail(&obj->global_link, &still_in_list);
206 if (!obj->mm.pages) {
207 list_del_init(&obj->global_link);
211 if (flags & I915_SHRINK_PURGEABLE &&
212 obj->mm.madv != I915_MADV_DONTNEED)
215 if (flags & I915_SHRINK_VMAPS &&
216 !is_vmalloc_addr(obj->mm.mapping))
219 if (!(flags & I915_SHRINK_ACTIVE) &&
220 (i915_gem_object_is_active(obj) ||
221 obj->framebuffer_references))
224 if (!can_release_pages(obj))
227 if (unsafe_drop_pages(obj)) {
228 /* May arrive from get_pages on another bo */
229 mutex_lock_nested(&obj->mm.lock,
231 if (!obj->mm.pages) {
232 __i915_gem_object_invalidate(obj);
233 list_del_init(&obj->global_link);
234 count += obj->base.size >> PAGE_SHIFT;
236 mutex_unlock(&obj->mm.lock);
239 list_splice_tail(&still_in_list, phase->list);
242 if (flags & I915_SHRINK_BOUND)
243 intel_runtime_pm_put(dev_priv);
245 i915_gem_retire_requests(dev_priv);
247 i915_gem_shrinker_unlock(&dev_priv->drm, unlock);
253 * i915_gem_shrink_all - Shrink buffer object caches completely
254 * @dev_priv: i915 device
256 * This is a simple wraper around i915_gem_shrink() to aggressively shrink all
257 * caches completely. It also first waits for and retires all outstanding
258 * requests to also be able to release backing storage for active objects.
260 * This should only be used in code to intentionally quiescent the gpu or as a
261 * last-ditch effort when memory seems to have run out.
264 * The number of pages of backing storage actually released.
266 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
270 freed = i915_gem_shrink(dev_priv, -1UL,
272 I915_SHRINK_UNBOUND |
274 synchronize_rcu(); /* wait for our earlier RCU delayed slab frees */
280 i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
282 struct drm_i915_private *dev_priv =
283 container_of(shrinker, struct drm_i915_private, mm.shrinker);
284 struct drm_device *dev = &dev_priv->drm;
285 struct drm_i915_gem_object *obj;
289 if (!i915_gem_shrinker_lock(dev, &unlock))
292 i915_gem_retire_requests(dev_priv);
295 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_link)
296 if (can_release_pages(obj))
297 count += obj->base.size >> PAGE_SHIFT;
299 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_link) {
300 if (!i915_gem_object_is_active(obj) && can_release_pages(obj))
301 count += obj->base.size >> PAGE_SHIFT;
304 i915_gem_shrinker_unlock(dev, unlock);
310 i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
312 struct drm_i915_private *dev_priv =
313 container_of(shrinker, struct drm_i915_private, mm.shrinker);
314 struct drm_device *dev = &dev_priv->drm;
318 if (!i915_gem_shrinker_lock(dev, &unlock))
321 freed = i915_gem_shrink(dev_priv,
324 I915_SHRINK_UNBOUND |
325 I915_SHRINK_PURGEABLE);
326 if (freed < sc->nr_to_scan)
327 freed += i915_gem_shrink(dev_priv,
328 sc->nr_to_scan - freed,
330 I915_SHRINK_UNBOUND);
332 i915_gem_shrinker_unlock(dev, unlock);
337 struct shrinker_lock_uninterruptible {
338 bool was_interruptible;
343 i915_gem_shrinker_lock_uninterruptible(struct drm_i915_private *dev_priv,
344 struct shrinker_lock_uninterruptible *slu,
347 unsigned long timeout = jiffies + msecs_to_jiffies_timeout(timeout_ms);
350 if (i915_gem_wait_for_idle(dev_priv, 0) == 0 &&
351 i915_gem_shrinker_lock(&dev_priv->drm, &slu->unlock))
354 schedule_timeout_killable(1);
355 if (fatal_signal_pending(current))
358 if (time_after(jiffies, timeout)) {
359 pr_err("Unable to lock GPU to purge memory.\n");
364 slu->was_interruptible = dev_priv->mm.interruptible;
365 dev_priv->mm.interruptible = false;
370 i915_gem_shrinker_unlock_uninterruptible(struct drm_i915_private *dev_priv,
371 struct shrinker_lock_uninterruptible *slu)
373 dev_priv->mm.interruptible = slu->was_interruptible;
374 i915_gem_shrinker_unlock(&dev_priv->drm, slu->unlock);
378 i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
380 struct drm_i915_private *dev_priv =
381 container_of(nb, struct drm_i915_private, mm.oom_notifier);
382 struct shrinker_lock_uninterruptible slu;
383 struct drm_i915_gem_object *obj;
384 unsigned long unevictable, bound, unbound, freed_pages;
386 if (!i915_gem_shrinker_lock_uninterruptible(dev_priv, &slu, 5000))
389 intel_runtime_pm_get(dev_priv);
390 freed_pages = i915_gem_shrink_all(dev_priv);
391 intel_runtime_pm_put(dev_priv);
393 /* Because we may be allocating inside our own driver, we cannot
394 * assert that there are no objects with pinned pages that are not
395 * being pointed to by hardware.
397 unbound = bound = unevictable = 0;
398 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_link) {
402 if (!can_release_pages(obj))
403 unevictable += obj->base.size >> PAGE_SHIFT;
405 unbound += obj->base.size >> PAGE_SHIFT;
407 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_link) {
411 if (!can_release_pages(obj))
412 unevictable += obj->base.size >> PAGE_SHIFT;
414 bound += obj->base.size >> PAGE_SHIFT;
417 i915_gem_shrinker_unlock_uninterruptible(dev_priv, &slu);
419 if (freed_pages || unbound || bound)
420 pr_info("Purging GPU memory, %lu pages freed, "
421 "%lu pages still pinned.\n",
422 freed_pages, unevictable);
423 if (unbound || bound)
424 pr_err("%lu and %lu pages still available in the "
425 "bound and unbound GPU page lists.\n",
428 *(unsigned long *)ptr += freed_pages;
433 i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
435 struct drm_i915_private *dev_priv =
436 container_of(nb, struct drm_i915_private, mm.vmap_notifier);
437 struct shrinker_lock_uninterruptible slu;
438 struct i915_vma *vma, *next;
439 unsigned long freed_pages = 0;
442 if (!i915_gem_shrinker_lock_uninterruptible(dev_priv, &slu, 5000))
445 /* Force everything onto the inactive lists */
446 ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED);
450 intel_runtime_pm_get(dev_priv);
451 freed_pages += i915_gem_shrink(dev_priv, -1UL,
453 I915_SHRINK_UNBOUND |
456 intel_runtime_pm_put(dev_priv);
458 /* We also want to clear any cached iomaps as they wrap vmap */
459 list_for_each_entry_safe(vma, next,
460 &dev_priv->ggtt.base.inactive_list, vm_link) {
461 unsigned long count = vma->node.size >> PAGE_SHIFT;
462 if (vma->iomap && i915_vma_unbind(vma) == 0)
463 freed_pages += count;
467 i915_gem_shrinker_unlock_uninterruptible(dev_priv, &slu);
469 *(unsigned long *)ptr += freed_pages;
474 * i915_gem_shrinker_init - Initialize i915 shrinker
475 * @dev_priv: i915 device
477 * This function registers and sets up the i915 shrinker and OOM handler.
479 void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
481 dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
482 dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count;
483 dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS;
484 WARN_ON(register_shrinker(&dev_priv->mm.shrinker));
486 dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
487 WARN_ON(register_oom_notifier(&dev_priv->mm.oom_notifier));
489 dev_priv->mm.vmap_notifier.notifier_call = i915_gem_shrinker_vmap;
490 WARN_ON(register_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
494 * i915_gem_shrinker_cleanup - Clean up i915 shrinker
495 * @dev_priv: i915 device
497 * This function unregisters the i915 shrinker and OOM handler.
499 void i915_gem_shrinker_cleanup(struct drm_i915_private *dev_priv)
501 WARN_ON(unregister_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
502 WARN_ON(unregister_oom_notifier(&dev_priv->mm.oom_notifier));
503 unregister_shrinker(&dev_priv->mm.shrinker);