1 /*
2 * Copyright © 2008-2015 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 */
24
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 <drm/drmP.h>
32 #include <drm/i915_drm.h>
33
34 #include "i915_drv.h"
35 #include "i915_trace.h"
36
mutex_is_locked_by(struct mutex * mutex,struct task_struct * task)37 static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
38 {
39 if (!mutex_is_locked(mutex))
40 return false;
41
42 #if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER)
43 return mutex->owner == task;
44 #else
45 /* Since UP may be pre-empted, we cannot assume that we own the lock */
46 return false;
47 #endif
48 }
49
50 /**
51 * i915_gem_shrink - Shrink buffer object caches
52 * @dev_priv: i915 device
53 * @target: amount of memory to make available, in pages
54 * @flags: control flags for selecting cache types
55 *
56 * This function is the main interface to the shrinker. It will try to release
57 * up to @target pages of main memory backing storage from buffer objects.
58 * Selection of the specific caches can be done with @flags. This is e.g. useful
59 * when purgeable objects should be removed from caches preferentially.
60 *
61 * Note that it's not guaranteed that released amount is actually available as
62 * free system memory - the pages might still be in-used to due to other reasons
63 * (like cpu mmaps) or the mm core has reused them before we could grab them.
64 * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
65 * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
66 *
67 * Also note that any kind of pinning (both per-vma address space pins and
68 * backing storage pins at the buffer object level) result in the shrinker code
69 * having to skip the object.
70 *
71 * Returns:
72 * The number of pages of backing storage actually released.
73 */
74 unsigned long
i915_gem_shrink(struct drm_i915_private * dev_priv,unsigned long target,unsigned flags)75 i915_gem_shrink(struct drm_i915_private *dev_priv,
76 unsigned long target, unsigned flags)
77 {
78 const struct {
79 struct list_head *list;
80 unsigned int bit;
81 } phases[] = {
82 { &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
83 { &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
84 { NULL, 0 },
85 }, *phase;
86 unsigned long count = 0;
87
88 trace_i915_gem_shrink(dev_priv, target, flags);
89 i915_gem_retire_requests(dev_priv->dev);
90
91 /*
92 * As we may completely rewrite the (un)bound list whilst unbinding
93 * (due to retiring requests) we have to strictly process only
94 * one element of the list at the time, and recheck the list
95 * on every iteration.
96 *
97 * In particular, we must hold a reference whilst removing the
98 * object as we may end up waiting for and/or retiring the objects.
99 * This might release the final reference (held by the active list)
100 * and result in the object being freed from under us. This is
101 * similar to the precautions the eviction code must take whilst
102 * removing objects.
103 *
104 * Also note that although these lists do not hold a reference to
105 * the object we can safely grab one here: The final object
106 * unreferencing and the bound_list are both protected by the
107 * dev->struct_mutex and so we won't ever be able to observe an
108 * object on the bound_list with a reference count equals 0.
109 */
110 for (phase = phases; phase->list; phase++) {
111 struct list_head still_in_list;
112
113 if ((flags & phase->bit) == 0)
114 continue;
115
116 INIT_LIST_HEAD(&still_in_list);
117 while (count < target && !list_empty(phase->list)) {
118 struct drm_i915_gem_object *obj;
119 struct i915_vma *vma, *v;
120
121 obj = list_first_entry(phase->list,
122 typeof(*obj), global_list);
123 list_move_tail(&obj->global_list, &still_in_list);
124
125 if (flags & I915_SHRINK_PURGEABLE &&
126 obj->madv != I915_MADV_DONTNEED)
127 continue;
128
129 if ((flags & I915_SHRINK_ACTIVE) == 0 && obj->active)
130 continue;
131
132 drm_gem_object_reference(&obj->base);
133
134 /* For the unbound phase, this should be a no-op! */
135 list_for_each_entry_safe(vma, v,
136 &obj->vma_list, vma_link)
137 if (i915_vma_unbind(vma))
138 break;
139
140 if (i915_gem_object_put_pages(obj) == 0)
141 count += obj->base.size >> PAGE_SHIFT;
142
143 drm_gem_object_unreference(&obj->base);
144 }
145 list_splice(&still_in_list, phase->list);
146 }
147
148 i915_gem_retire_requests(dev_priv->dev);
149
150 return count;
151 }
152
153 /**
154 * i915_gem_shrink_all - Shrink buffer object caches completely
155 * @dev_priv: i915 device
156 *
157 * This is a simple wraper around i915_gem_shrink() to aggressively shrink all
158 * caches completely. It also first waits for and retires all outstanding
159 * requests to also be able to release backing storage for active objects.
160 *
161 * This should only be used in code to intentionally quiescent the gpu or as a
162 * last-ditch effort when memory seems to have run out.
163 *
164 * Returns:
165 * The number of pages of backing storage actually released.
166 */
i915_gem_shrink_all(struct drm_i915_private * dev_priv)167 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
168 {
169 return i915_gem_shrink(dev_priv, -1UL,
170 I915_SHRINK_BOUND |
171 I915_SHRINK_UNBOUND |
172 I915_SHRINK_ACTIVE);
173 }
174
i915_gem_shrinker_lock(struct drm_device * dev,bool * unlock)175 static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
176 {
177 if (!mutex_trylock(&dev->struct_mutex)) {
178 if (!mutex_is_locked_by(&dev->struct_mutex, current))
179 return false;
180
181 if (to_i915(dev)->mm.shrinker_no_lock_stealing)
182 return false;
183
184 *unlock = false;
185 } else
186 *unlock = true;
187
188 return true;
189 }
190
num_vma_bound(struct drm_i915_gem_object * obj)191 static int num_vma_bound(struct drm_i915_gem_object *obj)
192 {
193 struct i915_vma *vma;
194 int count = 0;
195
196 list_for_each_entry(vma, &obj->vma_list, vma_link) {
197 if (drm_mm_node_allocated(&vma->node))
198 count++;
199 if (vma->pin_count)
200 count++;
201 }
202
203 return count;
204 }
205
206 static unsigned long
i915_gem_shrinker_count(struct shrinker * shrinker,struct shrink_control * sc)207 i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
208 {
209 struct drm_i915_private *dev_priv =
210 container_of(shrinker, struct drm_i915_private, mm.shrinker);
211 struct drm_device *dev = dev_priv->dev;
212 struct drm_i915_gem_object *obj;
213 unsigned long count;
214 bool unlock;
215
216 if (!i915_gem_shrinker_lock(dev, &unlock))
217 return 0;
218
219 count = 0;
220 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list)
221 if (obj->pages_pin_count == 0)
222 count += obj->base.size >> PAGE_SHIFT;
223
224 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
225 if (!obj->active && obj->pages_pin_count == num_vma_bound(obj))
226 count += obj->base.size >> PAGE_SHIFT;
227 }
228
229 if (unlock)
230 mutex_unlock(&dev->struct_mutex);
231
232 return count;
233 }
234
235 static unsigned long
i915_gem_shrinker_scan(struct shrinker * shrinker,struct shrink_control * sc)236 i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
237 {
238 struct drm_i915_private *dev_priv =
239 container_of(shrinker, struct drm_i915_private, mm.shrinker);
240 struct drm_device *dev = dev_priv->dev;
241 unsigned long freed;
242 bool unlock;
243
244 if (!i915_gem_shrinker_lock(dev, &unlock))
245 return SHRINK_STOP;
246
247 freed = i915_gem_shrink(dev_priv,
248 sc->nr_to_scan,
249 I915_SHRINK_BOUND |
250 I915_SHRINK_UNBOUND |
251 I915_SHRINK_PURGEABLE);
252 if (freed < sc->nr_to_scan)
253 freed += i915_gem_shrink(dev_priv,
254 sc->nr_to_scan - freed,
255 I915_SHRINK_BOUND |
256 I915_SHRINK_UNBOUND);
257 if (unlock)
258 mutex_unlock(&dev->struct_mutex);
259
260 return freed;
261 }
262
263 static int
i915_gem_shrinker_oom(struct notifier_block * nb,unsigned long event,void * ptr)264 i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
265 {
266 struct drm_i915_private *dev_priv =
267 container_of(nb, struct drm_i915_private, mm.oom_notifier);
268 struct drm_device *dev = dev_priv->dev;
269 struct drm_i915_gem_object *obj;
270 unsigned long timeout = msecs_to_jiffies(5000) + 1;
271 unsigned long pinned, bound, unbound, freed_pages;
272 bool was_interruptible;
273 bool unlock;
274
275 while (!i915_gem_shrinker_lock(dev, &unlock) && --timeout) {
276 schedule_timeout_killable(1);
277 if (fatal_signal_pending(current))
278 return NOTIFY_DONE;
279 }
280 if (timeout == 0) {
281 pr_err("Unable to purge GPU memory due lock contention.\n");
282 return NOTIFY_DONE;
283 }
284
285 was_interruptible = dev_priv->mm.interruptible;
286 dev_priv->mm.interruptible = false;
287
288 freed_pages = i915_gem_shrink_all(dev_priv);
289
290 dev_priv->mm.interruptible = was_interruptible;
291
292 /* Because we may be allocating inside our own driver, we cannot
293 * assert that there are no objects with pinned pages that are not
294 * being pointed to by hardware.
295 */
296 unbound = bound = pinned = 0;
297 list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list) {
298 if (!obj->base.filp) /* not backed by a freeable object */
299 continue;
300
301 if (obj->pages_pin_count)
302 pinned += obj->base.size;
303 else
304 unbound += obj->base.size;
305 }
306 list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
307 if (!obj->base.filp)
308 continue;
309
310 if (obj->pages_pin_count)
311 pinned += obj->base.size;
312 else
313 bound += obj->base.size;
314 }
315
316 if (unlock)
317 mutex_unlock(&dev->struct_mutex);
318
319 if (freed_pages || unbound || bound)
320 pr_info("Purging GPU memory, %lu bytes freed, %lu bytes still pinned.\n",
321 freed_pages << PAGE_SHIFT, pinned);
322 if (unbound || bound)
323 pr_err("%lu and %lu bytes still available in the "
324 "bound and unbound GPU page lists.\n",
325 bound, unbound);
326
327 *(unsigned long *)ptr += freed_pages;
328 return NOTIFY_DONE;
329 }
330
331 /**
332 * i915_gem_shrinker_init - Initialize i915 shrinker
333 * @dev_priv: i915 device
334 *
335 * This function registers and sets up the i915 shrinker and OOM handler.
336 */
i915_gem_shrinker_init(struct drm_i915_private * dev_priv)337 void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
338 {
339 dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
340 dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count;
341 dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS;
342 register_shrinker(&dev_priv->mm.shrinker);
343
344 dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
345 register_oom_notifier(&dev_priv->mm.oom_notifier);
346 }
347