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 shrinker_lock(struct drm_i915_private *dev_priv, bool *unlock)
40 switch (mutex_trylock_recursive(&dev_priv->drm.struct_mutex)) {
41 case MUTEX_TRYLOCK_FAILED:
44 case MUTEX_TRYLOCK_SUCCESS:
48 case MUTEX_TRYLOCK_RECURSIVE:
56 static void shrinker_unlock(struct drm_i915_private *dev_priv, bool unlock)
61 mutex_unlock(&dev_priv->drm.struct_mutex);
64 static bool any_vma_pinned(struct drm_i915_gem_object *obj)
68 list_for_each_entry(vma, &obj->vma_list, obj_link)
69 if (i915_vma_is_pinned(vma))
75 static bool swap_available(void)
77 return get_nr_swap_pages() > 0;
80 static bool can_release_pages(struct drm_i915_gem_object *obj)
85 /* Consider only shrinkable ojects. */
86 if (!i915_gem_object_is_shrinkable(obj))
89 /* Only report true if by unbinding the object and putting its pages
90 * we can actually make forward progress towards freeing physical
93 * If the pages are pinned for any other reason than being bound
94 * to the GPU, simply unbinding from the GPU is not going to succeed
95 * in releasing our pin count on the pages themselves.
97 if (atomic_read(&obj->mm.pages_pin_count) > obj->bind_count)
100 if (any_vma_pinned(obj))
103 /* We can only return physical pages to the system if we can either
104 * discard the contents (because the user has marked them as being
105 * purgeable) or if we can move their contents out to swap.
107 return swap_available() || obj->mm.madv == I915_MADV_DONTNEED;
110 static bool unsafe_drop_pages(struct drm_i915_gem_object *obj)
112 if (i915_gem_object_unbind(obj) == 0)
113 __i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
114 return !READ_ONCE(obj->mm.pages);
118 * i915_gem_shrink - Shrink buffer object caches
119 * @dev_priv: i915 device
120 * @target: amount of memory to make available, in pages
121 * @flags: control flags for selecting cache types
123 * This function is the main interface to the shrinker. It will try to release
124 * up to @target pages of main memory backing storage from buffer objects.
125 * Selection of the specific caches can be done with @flags. This is e.g. useful
126 * when purgeable objects should be removed from caches preferentially.
128 * Note that it's not guaranteed that released amount is actually available as
129 * free system memory - the pages might still be in-used to due to other reasons
130 * (like cpu mmaps) or the mm core has reused them before we could grab them.
131 * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
132 * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
134 * Also note that any kind of pinning (both per-vma address space pins and
135 * backing storage pins at the buffer object level) result in the shrinker code
136 * having to skip the object.
139 * The number of pages of backing storage actually released.
142 i915_gem_shrink(struct drm_i915_private *dev_priv,
143 unsigned long target, unsigned flags)
146 struct list_head *list;
149 { &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
150 { &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
153 unsigned long count = 0;
156 if (!shrinker_lock(dev_priv, &unlock))
159 trace_i915_gem_shrink(dev_priv, target, flags);
160 i915_gem_retire_requests(dev_priv);
163 * Unbinding of objects will require HW access; Let us not wake the
164 * device just to recover a little memory. If absolutely necessary,
165 * we will force the wake during oom-notifier.
167 if ((flags & I915_SHRINK_BOUND) &&
168 !intel_runtime_pm_get_if_in_use(dev_priv))
169 flags &= ~I915_SHRINK_BOUND;
172 * As we may completely rewrite the (un)bound list whilst unbinding
173 * (due to retiring requests) we have to strictly process only
174 * one element of the list at the time, and recheck the list
175 * on every iteration.
177 * In particular, we must hold a reference whilst removing the
178 * object as we may end up waiting for and/or retiring the objects.
179 * This might release the final reference (held by the active list)
180 * and result in the object being freed from under us. This is
181 * similar to the precautions the eviction code must take whilst
184 * Also note that although these lists do not hold a reference to
185 * the object we can safely grab one here: The final object
186 * unreferencing and the bound_list are both protected by the
187 * dev->struct_mutex and so we won't ever be able to observe an
188 * object on the bound_list with a reference count equals 0.
190 for (phase = phases; phase->list; phase++) {
191 struct list_head still_in_list;
192 struct drm_i915_gem_object *obj;
194 if ((flags & phase->bit) == 0)
197 INIT_LIST_HEAD(&still_in_list);
198 while (count < target &&
199 (obj = list_first_entry_or_null(phase->list,
202 list_move_tail(&obj->global_link, &still_in_list);
203 if (!obj->mm.pages) {
204 list_del_init(&obj->global_link);
208 if (flags & I915_SHRINK_PURGEABLE &&
209 obj->mm.madv != I915_MADV_DONTNEED)
212 if (flags & I915_SHRINK_VMAPS &&
213 !is_vmalloc_addr(obj->mm.mapping))
216 if (!(flags & I915_SHRINK_ACTIVE) &&
217 (i915_gem_object_is_active(obj) ||
218 i915_gem_object_is_framebuffer(obj)))
221 if (!can_release_pages(obj))
224 if (unsafe_drop_pages(obj)) {
225 /* May arrive from get_pages on another bo */
226 mutex_lock_nested(&obj->mm.lock,
228 if (!obj->mm.pages) {
229 __i915_gem_object_invalidate(obj);
230 list_del_init(&obj->global_link);
231 count += obj->base.size >> PAGE_SHIFT;
233 mutex_unlock(&obj->mm.lock);
236 list_splice_tail(&still_in_list, phase->list);
239 if (flags & I915_SHRINK_BOUND)
240 intel_runtime_pm_put(dev_priv);
242 i915_gem_retire_requests(dev_priv);
244 shrinker_unlock(dev_priv, unlock);
250 * i915_gem_shrink_all - Shrink buffer object caches completely
251 * @dev_priv: i915 device
253 * This is a simple wraper around i915_gem_shrink() to aggressively shrink all
254 * caches completely. It also first waits for and retires all outstanding
255 * requests to also be able to release backing storage for active objects.
257 * This should only be used in code to intentionally quiescent the gpu or as a
258 * last-ditch effort when memory seems to have run out.
261 * The number of pages of backing storage actually released.
263 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
267 intel_runtime_pm_get(dev_priv);
268 freed = i915_gem_shrink(dev_priv, -1UL,
270 I915_SHRINK_UNBOUND |
272 intel_runtime_pm_put(dev_priv);
278 i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
280 struct drm_i915_private *dev_priv =
281 container_of(shrinker, struct drm_i915_private, mm.shrinker);
282 struct drm_i915_gem_object *obj;
286 if (!shrinker_lock(dev_priv, &unlock))
289 i915_gem_retire_requests(dev_priv);
292 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_link)
293 if (can_release_pages(obj))
294 count += obj->base.size >> PAGE_SHIFT;
296 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_link) {
297 if (!i915_gem_object_is_active(obj) && can_release_pages(obj))
298 count += obj->base.size >> PAGE_SHIFT;
301 shrinker_unlock(dev_priv, unlock);
307 i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
309 struct drm_i915_private *dev_priv =
310 container_of(shrinker, struct drm_i915_private, mm.shrinker);
314 if (!shrinker_lock(dev_priv, &unlock))
317 freed = i915_gem_shrink(dev_priv,
320 I915_SHRINK_UNBOUND |
321 I915_SHRINK_PURGEABLE);
322 if (freed < sc->nr_to_scan)
323 freed += i915_gem_shrink(dev_priv,
324 sc->nr_to_scan - freed,
326 I915_SHRINK_UNBOUND);
328 shrinker_unlock(dev_priv, unlock);
334 shrinker_lock_uninterruptible(struct drm_i915_private *dev_priv, bool *unlock,
337 unsigned long timeout = jiffies + msecs_to_jiffies_timeout(timeout_ms);
340 if (i915_gem_wait_for_idle(dev_priv, 0) == 0 &&
341 shrinker_lock(dev_priv, unlock))
344 schedule_timeout_killable(1);
345 if (fatal_signal_pending(current))
348 if (time_after(jiffies, timeout)) {
349 pr_err("Unable to lock GPU to purge memory.\n");
358 i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
360 struct drm_i915_private *dev_priv =
361 container_of(nb, struct drm_i915_private, mm.oom_notifier);
362 struct drm_i915_gem_object *obj;
363 unsigned long unevictable, bound, unbound, freed_pages;
366 if (!shrinker_lock_uninterruptible(dev_priv, &unlock, 5000))
369 freed_pages = i915_gem_shrink_all(dev_priv);
371 /* Because we may be allocating inside our own driver, we cannot
372 * assert that there are no objects with pinned pages that are not
373 * being pointed to by hardware.
375 unbound = bound = unevictable = 0;
376 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_link) {
380 if (!can_release_pages(obj))
381 unevictable += obj->base.size >> PAGE_SHIFT;
383 unbound += obj->base.size >> PAGE_SHIFT;
385 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_link) {
389 if (!can_release_pages(obj))
390 unevictable += obj->base.size >> PAGE_SHIFT;
392 bound += obj->base.size >> PAGE_SHIFT;
395 shrinker_unlock(dev_priv, unlock);
397 if (freed_pages || unbound || bound)
398 pr_info("Purging GPU memory, %lu pages freed, "
399 "%lu pages still pinned.\n",
400 freed_pages, unevictable);
401 if (unbound || bound)
402 pr_err("%lu and %lu pages still available in the "
403 "bound and unbound GPU page lists.\n",
406 *(unsigned long *)ptr += freed_pages;
411 i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
413 struct drm_i915_private *dev_priv =
414 container_of(nb, struct drm_i915_private, mm.vmap_notifier);
415 struct i915_vma *vma, *next;
416 unsigned long freed_pages = 0;
420 if (!shrinker_lock_uninterruptible(dev_priv, &unlock, 5000))
423 /* Force everything onto the inactive lists */
424 ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED);
428 intel_runtime_pm_get(dev_priv);
429 freed_pages += i915_gem_shrink(dev_priv, -1UL,
431 I915_SHRINK_UNBOUND |
434 intel_runtime_pm_put(dev_priv);
436 /* We also want to clear any cached iomaps as they wrap vmap */
437 list_for_each_entry_safe(vma, next,
438 &dev_priv->ggtt.base.inactive_list, vm_link) {
439 unsigned long count = vma->node.size >> PAGE_SHIFT;
440 if (vma->iomap && i915_vma_unbind(vma) == 0)
441 freed_pages += count;
445 shrinker_unlock(dev_priv, unlock);
447 *(unsigned long *)ptr += freed_pages;
452 * i915_gem_shrinker_init - Initialize i915 shrinker
453 * @dev_priv: i915 device
455 * This function registers and sets up the i915 shrinker and OOM handler.
457 void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
459 dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
460 dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count;
461 dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS;
462 WARN_ON(register_shrinker(&dev_priv->mm.shrinker));
464 dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
465 WARN_ON(register_oom_notifier(&dev_priv->mm.oom_notifier));
467 dev_priv->mm.vmap_notifier.notifier_call = i915_gem_shrinker_vmap;
468 WARN_ON(register_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
472 * i915_gem_shrinker_cleanup - Clean up i915 shrinker
473 * @dev_priv: i915 device
475 * This function unregisters the i915 shrinker and OOM handler.
477 void i915_gem_shrinker_cleanup(struct drm_i915_private *dev_priv)
479 WARN_ON(unregister_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
480 WARN_ON(unregister_oom_notifier(&dev_priv->mm.oom_notifier));
481 unregister_shrinker(&dev_priv->mm.shrinker);