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_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER)
44 return mutex->owner == task;
46 /* Since UP may be pre-empted, we cannot assume that we own the lock */
51 static bool any_vma_pinned(struct drm_i915_gem_object *obj)
55 list_for_each_entry(vma, &obj->vma_list, obj_link)
56 if (i915_vma_is_pinned(vma))
62 static bool swap_available(void)
64 return get_nr_swap_pages() > 0;
67 static bool can_release_pages(struct drm_i915_gem_object *obj)
69 /* Only shmemfs objects are backed by swap */
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 > obj->bind_count)
84 if (any_vma_pinned(obj))
87 /* We can only return physical pages to the system if we can either
88 * discard the contents (because the user has marked them as being
89 * purgeable) or if we can move their contents out to swap.
91 return swap_available() || obj->madv == I915_MADV_DONTNEED;
95 * i915_gem_shrink - Shrink buffer object caches
96 * @dev_priv: i915 device
97 * @target: amount of memory to make available, in pages
98 * @flags: control flags for selecting cache types
100 * This function is the main interface to the shrinker. It will try to release
101 * up to @target pages of main memory backing storage from buffer objects.
102 * Selection of the specific caches can be done with @flags. This is e.g. useful
103 * when purgeable objects should be removed from caches preferentially.
105 * Note that it's not guaranteed that released amount is actually available as
106 * free system memory - the pages might still be in-used to due to other reasons
107 * (like cpu mmaps) or the mm core has reused them before we could grab them.
108 * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
109 * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
111 * Also note that any kind of pinning (both per-vma address space pins and
112 * backing storage pins at the buffer object level) result in the shrinker code
113 * having to skip the object.
116 * The number of pages of backing storage actually released.
119 i915_gem_shrink(struct drm_i915_private *dev_priv,
120 unsigned long target, unsigned flags)
123 struct list_head *list;
126 { &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
127 { &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
130 unsigned long count = 0;
132 trace_i915_gem_shrink(dev_priv, target, flags);
133 i915_gem_retire_requests(dev_priv);
136 * Unbinding of objects will require HW access; Let us not wake the
137 * device just to recover a little memory. If absolutely necessary,
138 * we will force the wake during oom-notifier.
140 if ((flags & I915_SHRINK_BOUND) &&
141 !intel_runtime_pm_get_if_in_use(dev_priv))
142 flags &= ~I915_SHRINK_BOUND;
145 * As we may completely rewrite the (un)bound list whilst unbinding
146 * (due to retiring requests) we have to strictly process only
147 * one element of the list at the time, and recheck the list
148 * on every iteration.
150 * In particular, we must hold a reference whilst removing the
151 * object as we may end up waiting for and/or retiring the objects.
152 * This might release the final reference (held by the active list)
153 * and result in the object being freed from under us. This is
154 * similar to the precautions the eviction code must take whilst
157 * Also note that although these lists do not hold a reference to
158 * the object we can safely grab one here: The final object
159 * unreferencing and the bound_list are both protected by the
160 * dev->struct_mutex and so we won't ever be able to observe an
161 * object on the bound_list with a reference count equals 0.
163 for (phase = phases; phase->list; phase++) {
164 struct list_head still_in_list;
165 struct drm_i915_gem_object *obj;
167 if ((flags & phase->bit) == 0)
170 INIT_LIST_HEAD(&still_in_list);
171 while (count < target &&
172 (obj = list_first_entry_or_null(phase->list,
175 list_move_tail(&obj->global_list, &still_in_list);
177 if (flags & I915_SHRINK_PURGEABLE &&
178 obj->madv != I915_MADV_DONTNEED)
181 if (flags & I915_SHRINK_VMAPS &&
182 !is_vmalloc_addr(obj->mapping))
185 if ((flags & I915_SHRINK_ACTIVE) == 0 &&
186 i915_gem_object_is_active(obj))
189 if (!can_release_pages(obj))
192 i915_gem_object_get(obj);
194 /* For the unbound phase, this should be a no-op! */
195 i915_gem_object_unbind(obj);
196 if (i915_gem_object_put_pages(obj) == 0)
197 count += obj->base.size >> PAGE_SHIFT;
199 i915_gem_object_put(obj);
201 list_splice(&still_in_list, phase->list);
204 if (flags & I915_SHRINK_BOUND)
205 intel_runtime_pm_put(dev_priv);
207 i915_gem_retire_requests(dev_priv);
208 /* expedite the RCU grace period to free some request slabs */
209 synchronize_rcu_expedited();
215 * i915_gem_shrink_all - Shrink buffer object caches completely
216 * @dev_priv: i915 device
218 * This is a simple wraper around i915_gem_shrink() to aggressively shrink all
219 * caches completely. It also first waits for and retires all outstanding
220 * requests to also be able to release backing storage for active objects.
222 * This should only be used in code to intentionally quiescent the gpu or as a
223 * last-ditch effort when memory seems to have run out.
226 * The number of pages of backing storage actually released.
228 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
232 freed = i915_gem_shrink(dev_priv, -1UL,
234 I915_SHRINK_UNBOUND |
236 rcu_barrier(); /* wait until our RCU delayed slab frees are completed */
241 static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
243 if (!mutex_trylock(&dev->struct_mutex)) {
244 if (!mutex_is_locked_by(&dev->struct_mutex, current))
255 i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
257 struct drm_i915_private *dev_priv =
258 container_of(shrinker, struct drm_i915_private, mm.shrinker);
259 struct drm_device *dev = &dev_priv->drm;
260 struct drm_i915_gem_object *obj;
264 if (!i915_gem_shrinker_lock(dev, &unlock))
267 i915_gem_retire_requests(dev_priv);
270 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list)
271 if (can_release_pages(obj))
272 count += obj->base.size >> PAGE_SHIFT;
274 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
275 if (!i915_gem_object_is_active(obj) && can_release_pages(obj))
276 count += obj->base.size >> PAGE_SHIFT;
280 mutex_unlock(&dev->struct_mutex);
286 i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
288 struct drm_i915_private *dev_priv =
289 container_of(shrinker, struct drm_i915_private, mm.shrinker);
290 struct drm_device *dev = &dev_priv->drm;
294 if (!i915_gem_shrinker_lock(dev, &unlock))
297 freed = i915_gem_shrink(dev_priv,
300 I915_SHRINK_UNBOUND |
301 I915_SHRINK_PURGEABLE);
302 if (freed < sc->nr_to_scan)
303 freed += i915_gem_shrink(dev_priv,
304 sc->nr_to_scan - freed,
306 I915_SHRINK_UNBOUND);
308 mutex_unlock(&dev->struct_mutex);
313 struct shrinker_lock_uninterruptible {
314 bool was_interruptible;
319 i915_gem_shrinker_lock_uninterruptible(struct drm_i915_private *dev_priv,
320 struct shrinker_lock_uninterruptible *slu,
323 unsigned long timeout = jiffies + msecs_to_jiffies_timeout(timeout_ms);
326 if (i915_gem_wait_for_idle(dev_priv, 0) == 0 &&
327 i915_gem_shrinker_lock(&dev_priv->drm, &slu->unlock))
330 schedule_timeout_killable(1);
331 if (fatal_signal_pending(current))
334 if (time_after(jiffies, timeout)) {
335 pr_err("Unable to lock GPU to purge memory.\n");
340 slu->was_interruptible = dev_priv->mm.interruptible;
341 dev_priv->mm.interruptible = false;
346 i915_gem_shrinker_unlock_uninterruptible(struct drm_i915_private *dev_priv,
347 struct shrinker_lock_uninterruptible *slu)
349 dev_priv->mm.interruptible = slu->was_interruptible;
351 mutex_unlock(&dev_priv->drm.struct_mutex);
355 i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
357 struct drm_i915_private *dev_priv =
358 container_of(nb, struct drm_i915_private, mm.oom_notifier);
359 struct shrinker_lock_uninterruptible slu;
360 struct drm_i915_gem_object *obj;
361 unsigned long unevictable, bound, unbound, freed_pages;
363 if (!i915_gem_shrinker_lock_uninterruptible(dev_priv, &slu, 5000))
366 intel_runtime_pm_get(dev_priv);
367 freed_pages = i915_gem_shrink_all(dev_priv);
368 intel_runtime_pm_put(dev_priv);
370 /* Because we may be allocating inside our own driver, we cannot
371 * assert that there are no objects with pinned pages that are not
372 * being pointed to by hardware.
374 unbound = bound = unevictable = 0;
375 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list) {
376 if (!can_release_pages(obj))
377 unevictable += obj->base.size >> PAGE_SHIFT;
379 unbound += obj->base.size >> PAGE_SHIFT;
381 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
382 if (!can_release_pages(obj))
383 unevictable += obj->base.size >> PAGE_SHIFT;
385 bound += obj->base.size >> PAGE_SHIFT;
388 i915_gem_shrinker_unlock_uninterruptible(dev_priv, &slu);
390 if (freed_pages || unbound || bound)
391 pr_info("Purging GPU memory, %lu pages freed, "
392 "%lu pages still pinned.\n",
393 freed_pages, unevictable);
394 if (unbound || bound)
395 pr_err("%lu and %lu pages still available in the "
396 "bound and unbound GPU page lists.\n",
399 *(unsigned long *)ptr += freed_pages;
404 i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
406 struct drm_i915_private *dev_priv =
407 container_of(nb, struct drm_i915_private, mm.vmap_notifier);
408 struct shrinker_lock_uninterruptible slu;
409 struct i915_vma *vma, *next;
410 unsigned long freed_pages = 0;
413 if (!i915_gem_shrinker_lock_uninterruptible(dev_priv, &slu, 5000))
416 /* Force everything onto the inactive lists */
417 ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED);
421 intel_runtime_pm_get(dev_priv);
422 freed_pages += i915_gem_shrink(dev_priv, -1UL,
424 I915_SHRINK_UNBOUND |
427 intel_runtime_pm_put(dev_priv);
429 /* We also want to clear any cached iomaps as they wrap vmap */
430 list_for_each_entry_safe(vma, next,
431 &dev_priv->ggtt.base.inactive_list, vm_link) {
432 unsigned long count = vma->node.size >> PAGE_SHIFT;
433 if (vma->iomap && i915_vma_unbind(vma) == 0)
434 freed_pages += count;
438 i915_gem_shrinker_unlock_uninterruptible(dev_priv, &slu);
440 *(unsigned long *)ptr += freed_pages;
445 * i915_gem_shrinker_init - Initialize i915 shrinker
446 * @dev_priv: i915 device
448 * This function registers and sets up the i915 shrinker and OOM handler.
450 void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
452 dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
453 dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count;
454 dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS;
455 WARN_ON(register_shrinker(&dev_priv->mm.shrinker));
457 dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
458 WARN_ON(register_oom_notifier(&dev_priv->mm.oom_notifier));
460 dev_priv->mm.vmap_notifier.notifier_call = i915_gem_shrinker_vmap;
461 WARN_ON(register_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
465 * i915_gem_shrinker_cleanup - Clean up i915 shrinker
466 * @dev_priv: i915 device
468 * This function unregisters the i915 shrinker and OOM handler.
470 void i915_gem_shrinker_cleanup(struct drm_i915_private *dev_priv)
472 WARN_ON(unregister_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
473 WARN_ON(unregister_oom_notifier(&dev_priv->mm.oom_notifier));
474 unregister_shrinker(&dev_priv->mm.shrinker);