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_RECURSIVE:
45 case MUTEX_TRYLOCK_FAILED:
48 if (mutex_trylock(&dev_priv->drm.struct_mutex)) {
49 case MUTEX_TRYLOCK_SUCCESS:
53 } while (!need_resched());
61 static void shrinker_unlock(struct drm_i915_private *dev_priv, bool unlock)
66 mutex_unlock(&dev_priv->drm.struct_mutex);
69 static bool any_vma_pinned(struct drm_i915_gem_object *obj)
73 list_for_each_entry(vma, &obj->vma_list, obj_link) {
74 /* Only GGTT vma may be permanently pinned, and are always
75 * at the start of the list. We can stop hunting as soon
76 * as we see a ppGTT vma.
78 if (!i915_vma_is_ggtt(vma))
81 if (i915_vma_is_pinned(vma))
88 static bool swap_available(void)
90 return get_nr_swap_pages() > 0;
93 static bool can_release_pages(struct drm_i915_gem_object *obj)
98 /* Consider only shrinkable ojects. */
99 if (!i915_gem_object_is_shrinkable(obj))
102 /* Only report true if by unbinding the object and putting its pages
103 * we can actually make forward progress towards freeing physical
106 * If the pages are pinned for any other reason than being bound
107 * to the GPU, simply unbinding from the GPU is not going to succeed
108 * in releasing our pin count on the pages themselves.
110 if (atomic_read(&obj->mm.pages_pin_count) > obj->bind_count)
113 if (any_vma_pinned(obj))
116 /* We can only return physical pages to the system if we can either
117 * discard the contents (because the user has marked them as being
118 * purgeable) or if we can move their contents out to swap.
120 return swap_available() || obj->mm.madv == I915_MADV_DONTNEED;
123 static bool unsafe_drop_pages(struct drm_i915_gem_object *obj)
125 if (i915_gem_object_unbind(obj) == 0)
126 __i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
127 return !READ_ONCE(obj->mm.pages);
131 * i915_gem_shrink - Shrink buffer object caches
132 * @dev_priv: i915 device
133 * @target: amount of memory to make available, in pages
134 * @flags: control flags for selecting cache types
136 * This function is the main interface to the shrinker. It will try to release
137 * up to @target pages of main memory backing storage from buffer objects.
138 * Selection of the specific caches can be done with @flags. This is e.g. useful
139 * when purgeable objects should be removed from caches preferentially.
141 * Note that it's not guaranteed that released amount is actually available as
142 * free system memory - the pages might still be in-used to due to other reasons
143 * (like cpu mmaps) or the mm core has reused them before we could grab them.
144 * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
145 * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
147 * Also note that any kind of pinning (both per-vma address space pins and
148 * backing storage pins at the buffer object level) result in the shrinker code
149 * having to skip the object.
152 * The number of pages of backing storage actually released.
155 i915_gem_shrink(struct drm_i915_private *dev_priv,
156 unsigned long target, unsigned flags)
159 struct list_head *list;
162 { &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
163 { &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
166 unsigned long count = 0;
169 if (!shrinker_lock(dev_priv, &unlock))
172 trace_i915_gem_shrink(dev_priv, target, flags);
173 i915_gem_retire_requests(dev_priv);
176 * Unbinding of objects will require HW access; Let us not wake the
177 * device just to recover a little memory. If absolutely necessary,
178 * we will force the wake during oom-notifier.
180 if ((flags & I915_SHRINK_BOUND) &&
181 !intel_runtime_pm_get_if_in_use(dev_priv))
182 flags &= ~I915_SHRINK_BOUND;
185 * As we may completely rewrite the (un)bound list whilst unbinding
186 * (due to retiring requests) we have to strictly process only
187 * one element of the list at the time, and recheck the list
188 * on every iteration.
190 * In particular, we must hold a reference whilst removing the
191 * object as we may end up waiting for and/or retiring the objects.
192 * This might release the final reference (held by the active list)
193 * and result in the object being freed from under us. This is
194 * similar to the precautions the eviction code must take whilst
197 * Also note that although these lists do not hold a reference to
198 * the object we can safely grab one here: The final object
199 * unreferencing and the bound_list are both protected by the
200 * dev->struct_mutex and so we won't ever be able to observe an
201 * object on the bound_list with a reference count equals 0.
203 for (phase = phases; phase->list; phase++) {
204 struct list_head still_in_list;
205 struct drm_i915_gem_object *obj;
207 if ((flags & phase->bit) == 0)
210 INIT_LIST_HEAD(&still_in_list);
211 while (count < target &&
212 (obj = list_first_entry_or_null(phase->list,
215 list_move_tail(&obj->global_link, &still_in_list);
216 if (!obj->mm.pages) {
217 list_del_init(&obj->global_link);
221 if (flags & I915_SHRINK_PURGEABLE &&
222 obj->mm.madv != I915_MADV_DONTNEED)
225 if (flags & I915_SHRINK_VMAPS &&
226 !is_vmalloc_addr(obj->mm.mapping))
229 if (!(flags & I915_SHRINK_ACTIVE) &&
230 (i915_gem_object_is_active(obj) ||
231 i915_gem_object_is_framebuffer(obj)))
234 if (!can_release_pages(obj))
237 if (unsafe_drop_pages(obj)) {
238 /* May arrive from get_pages on another bo */
239 mutex_lock_nested(&obj->mm.lock,
241 if (!obj->mm.pages) {
242 __i915_gem_object_invalidate(obj);
243 list_del_init(&obj->global_link);
244 count += obj->base.size >> PAGE_SHIFT;
246 mutex_unlock(&obj->mm.lock);
249 list_splice_tail(&still_in_list, phase->list);
252 if (flags & I915_SHRINK_BOUND)
253 intel_runtime_pm_put(dev_priv);
255 i915_gem_retire_requests(dev_priv);
257 shrinker_unlock(dev_priv, unlock);
263 * i915_gem_shrink_all - Shrink buffer object caches completely
264 * @dev_priv: i915 device
266 * This is a simple wraper around i915_gem_shrink() to aggressively shrink all
267 * caches completely. It also first waits for and retires all outstanding
268 * requests to also be able to release backing storage for active objects.
270 * This should only be used in code to intentionally quiescent the gpu or as a
271 * last-ditch effort when memory seems to have run out.
274 * The number of pages of backing storage actually released.
276 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
280 intel_runtime_pm_get(dev_priv);
281 freed = i915_gem_shrink(dev_priv, -1UL,
283 I915_SHRINK_UNBOUND |
285 intel_runtime_pm_put(dev_priv);
291 i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
293 struct drm_i915_private *dev_priv =
294 container_of(shrinker, struct drm_i915_private, mm.shrinker);
295 struct drm_i915_gem_object *obj;
299 if (!shrinker_lock(dev_priv, &unlock))
302 i915_gem_retire_requests(dev_priv);
305 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_link)
306 if (can_release_pages(obj))
307 count += obj->base.size >> PAGE_SHIFT;
309 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_link) {
310 if (!i915_gem_object_is_active(obj) && can_release_pages(obj))
311 count += obj->base.size >> PAGE_SHIFT;
314 shrinker_unlock(dev_priv, unlock);
320 i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
322 struct drm_i915_private *dev_priv =
323 container_of(shrinker, struct drm_i915_private, mm.shrinker);
327 if (!shrinker_lock(dev_priv, &unlock))
330 freed = i915_gem_shrink(dev_priv,
333 I915_SHRINK_UNBOUND |
334 I915_SHRINK_PURGEABLE);
335 if (freed < sc->nr_to_scan)
336 freed += i915_gem_shrink(dev_priv,
337 sc->nr_to_scan - freed,
339 I915_SHRINK_UNBOUND);
340 if (freed < sc->nr_to_scan && current_is_kswapd()) {
341 intel_runtime_pm_get(dev_priv);
342 freed += i915_gem_shrink(dev_priv,
343 sc->nr_to_scan - freed,
346 I915_SHRINK_UNBOUND);
347 intel_runtime_pm_put(dev_priv);
350 shrinker_unlock(dev_priv, unlock);
356 shrinker_lock_uninterruptible(struct drm_i915_private *dev_priv, bool *unlock,
359 unsigned long timeout = jiffies + msecs_to_jiffies_timeout(timeout_ms);
362 if (i915_gem_wait_for_idle(dev_priv, 0) == 0 &&
363 shrinker_lock(dev_priv, unlock))
366 schedule_timeout_killable(1);
367 if (fatal_signal_pending(current))
370 if (time_after(jiffies, timeout)) {
371 pr_err("Unable to lock GPU to purge memory.\n");
380 i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
382 struct drm_i915_private *dev_priv =
383 container_of(nb, struct drm_i915_private, mm.oom_notifier);
384 struct drm_i915_gem_object *obj;
385 unsigned long unevictable, bound, unbound, freed_pages;
388 if (!shrinker_lock_uninterruptible(dev_priv, &unlock, 5000))
391 freed_pages = i915_gem_shrink_all(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 shrinker_unlock(dev_priv, unlock);
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 i915_vma *vma, *next;
438 unsigned long freed_pages = 0;
442 if (!shrinker_lock_uninterruptible(dev_priv, &unlock, 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 shrinker_unlock(dev_priv, unlock);
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);