source: src/linux/universal/linux-4.9/drivers/gpu/drm/i915/i915_gem_shrinker.c @ 31574

Last change on this file since 31574 was 31574, checked in by brainslayer, 7 weeks ago

kernel 4.9 update

File size: 14.1 KB
Line 
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 <linux/vmalloc.h>
32#include <drm/drmP.h>
33#include <drm/i915_drm.h>
34
35#include "i915_drv.h"
36#include "i915_trace.h"
37
38static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
39{
40        if (!mutex_is_locked(mutex))
41                return false;
42
43#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER)
44        return mutex->owner == task;
45#else
46        /* Since UP may be pre-empted, we cannot assume that we own the lock */
47        return false;
48#endif
49}
50
51static bool any_vma_pinned(struct drm_i915_gem_object *obj)
52{
53        struct i915_vma *vma;
54
55        list_for_each_entry(vma, &obj->vma_list, obj_link)
56                if (i915_vma_is_pinned(vma))
57                        return true;
58
59        return false;
60}
61
62static bool swap_available(void)
63{
64        return get_nr_swap_pages() > 0;
65}
66
67static bool can_release_pages(struct drm_i915_gem_object *obj)
68{
69        /* Only shmemfs objects are backed by swap */
70        if (!obj->base.filp)
71                return false;
72
73        /* Only report true if by unbinding the object and putting its pages
74         * we can actually make forward progress towards freeing physical
75         * pages.
76         *
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.
80         */
81        if (obj->pages_pin_count > obj->bind_count)
82                return false;
83
84        if (any_vma_pinned(obj))
85                return false;
86
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.
90         */
91        return swap_available() || obj->madv == I915_MADV_DONTNEED;
92}
93
94/**
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
99 *
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.
104 *
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().
110 *
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.
114 *
115 * Returns:
116 * The number of pages of backing storage actually released.
117 */
118unsigned long
119i915_gem_shrink(struct drm_i915_private *dev_priv,
120                unsigned long target, unsigned flags)
121{
122        const struct {
123                struct list_head *list;
124                unsigned int bit;
125        } phases[] = {
126                { &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
127                { &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
128                { NULL, 0 },
129        }, *phase;
130        unsigned long count = 0;
131
132        trace_i915_gem_shrink(dev_priv, target, flags);
133        i915_gem_retire_requests(dev_priv);
134
135        /*
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.
139         */
140        if ((flags & I915_SHRINK_BOUND) &&
141            !intel_runtime_pm_get_if_in_use(dev_priv))
142                flags &= ~I915_SHRINK_BOUND;
143
144        /*
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.
149         *
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
155         * removing objects.
156         *
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.
162         */
163        for (phase = phases; phase->list; phase++) {
164                struct list_head still_in_list;
165                struct drm_i915_gem_object *obj;
166
167                if ((flags & phase->bit) == 0)
168                        continue;
169
170                INIT_LIST_HEAD(&still_in_list);
171                while (count < target &&
172                       (obj = list_first_entry_or_null(phase->list,
173                                                       typeof(*obj),
174                                                       global_list))) {
175                        list_move_tail(&obj->global_list, &still_in_list);
176
177                        if (flags & I915_SHRINK_PURGEABLE &&
178                            obj->madv != I915_MADV_DONTNEED)
179                                continue;
180
181                        if (flags & I915_SHRINK_VMAPS &&
182                            !is_vmalloc_addr(obj->mapping))
183                                continue;
184
185                        if ((flags & I915_SHRINK_ACTIVE) == 0 &&
186                            i915_gem_object_is_active(obj))
187                                continue;
188
189                        if (!can_release_pages(obj))
190                                continue;
191
192                        i915_gem_object_get(obj);
193
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;
198
199                        i915_gem_object_put(obj);
200                }
201                list_splice(&still_in_list, phase->list);
202        }
203
204        if (flags & I915_SHRINK_BOUND)
205                intel_runtime_pm_put(dev_priv);
206
207        i915_gem_retire_requests(dev_priv);
208        /* expedite the RCU grace period to free some request slabs */
209        synchronize_rcu_expedited();
210
211        return count;
212}
213
214/**
215 * i915_gem_shrink_all - Shrink buffer object caches completely
216 * @dev_priv: i915 device
217 *
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.
221 *
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.
224 *
225 * Returns:
226 * The number of pages of backing storage actually released.
227 */
228unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
229{
230        unsigned long freed;
231
232        freed = i915_gem_shrink(dev_priv, -1UL,
233                                I915_SHRINK_BOUND |
234                                I915_SHRINK_UNBOUND |
235                                I915_SHRINK_ACTIVE);
236        rcu_barrier(); /* wait until our RCU delayed slab frees are completed */
237
238        return freed;
239}
240
241static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
242{
243        if (!mutex_trylock(&dev->struct_mutex)) {
244                if (!mutex_is_locked_by(&dev->struct_mutex, current))
245                        return false;
246
247                *unlock = false;
248        } else
249                *unlock = true;
250
251        return true;
252}
253
254static unsigned long
255i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
256{
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;
261        unsigned long count;
262        bool unlock;
263
264        if (!i915_gem_shrinker_lock(dev, &unlock))
265                return 0;
266
267        i915_gem_retire_requests(dev_priv);
268
269        count = 0;
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;
273
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;
277        }
278
279        if (unlock)
280                mutex_unlock(&dev->struct_mutex);
281
282        return count;
283}
284
285static unsigned long
286i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
287{
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;
291        unsigned long freed;
292        bool unlock;
293
294        if (!i915_gem_shrinker_lock(dev, &unlock))
295                return SHRINK_STOP;
296
297        freed = i915_gem_shrink(dev_priv,
298                                sc->nr_to_scan,
299                                I915_SHRINK_BOUND |
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,
305                                         I915_SHRINK_BOUND |
306                                         I915_SHRINK_UNBOUND);
307        if (unlock)
308                mutex_unlock(&dev->struct_mutex);
309
310        return freed;
311}
312
313struct shrinker_lock_uninterruptible {
314        bool was_interruptible;
315        bool unlock;
316};
317
318static bool
319i915_gem_shrinker_lock_uninterruptible(struct drm_i915_private *dev_priv,
320                                       struct shrinker_lock_uninterruptible *slu,
321                                       int timeout_ms)
322{
323        unsigned long timeout = jiffies + msecs_to_jiffies_timeout(timeout_ms);
324
325        do {
326                if (i915_gem_wait_for_idle(dev_priv, 0) == 0 &&
327                    i915_gem_shrinker_lock(&dev_priv->drm, &slu->unlock))
328                        break;
329
330                schedule_timeout_killable(1);
331                if (fatal_signal_pending(current))
332                        return false;
333
334                if (time_after(jiffies, timeout)) {
335                        pr_err("Unable to lock GPU to purge memory.\n");
336                        return false;
337                }
338        } while (1);
339
340        slu->was_interruptible = dev_priv->mm.interruptible;
341        dev_priv->mm.interruptible = false;
342        return true;
343}
344
345static void
346i915_gem_shrinker_unlock_uninterruptible(struct drm_i915_private *dev_priv,
347                                         struct shrinker_lock_uninterruptible *slu)
348{
349        dev_priv->mm.interruptible = slu->was_interruptible;
350        if (slu->unlock)
351                mutex_unlock(&dev_priv->drm.struct_mutex);
352}
353
354static int
355i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
356{
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;
362
363        if (!i915_gem_shrinker_lock_uninterruptible(dev_priv, &slu, 5000))
364                return NOTIFY_DONE;
365
366        intel_runtime_pm_get(dev_priv);
367        freed_pages = i915_gem_shrink_all(dev_priv);
368        intel_runtime_pm_put(dev_priv);
369
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.
373         */
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;
378                else
379                        unbound += obj->base.size >> PAGE_SHIFT;
380        }
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;
384                else
385                        bound += obj->base.size >> PAGE_SHIFT;
386        }
387
388        i915_gem_shrinker_unlock_uninterruptible(dev_priv, &slu);
389
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",
397                       bound, unbound);
398
399        *(unsigned long *)ptr += freed_pages;
400        return NOTIFY_DONE;
401}
402
403static int
404i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
405{
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;
411        int ret;
412
413        if (!i915_gem_shrinker_lock_uninterruptible(dev_priv, &slu, 5000))
414                return NOTIFY_DONE;
415
416        /* Force everything onto the inactive lists */
417        ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED);
418        if (ret)
419                goto out;
420
421        intel_runtime_pm_get(dev_priv);
422        freed_pages += i915_gem_shrink(dev_priv, -1UL,
423                                       I915_SHRINK_BOUND |
424                                       I915_SHRINK_UNBOUND |
425                                       I915_SHRINK_ACTIVE |
426                                       I915_SHRINK_VMAPS);
427        intel_runtime_pm_put(dev_priv);
428
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;
435        }
436
437out:
438        i915_gem_shrinker_unlock_uninterruptible(dev_priv, &slu);
439
440        *(unsigned long *)ptr += freed_pages;
441        return NOTIFY_DONE;
442}
443
444/**
445 * i915_gem_shrinker_init - Initialize i915 shrinker
446 * @dev_priv: i915 device
447 *
448 * This function registers and sets up the i915 shrinker and OOM handler.
449 */
450void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
451{
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));
456
457        dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
458        WARN_ON(register_oom_notifier(&dev_priv->mm.oom_notifier));
459
460        dev_priv->mm.vmap_notifier.notifier_call = i915_gem_shrinker_vmap;
461        WARN_ON(register_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
462}
463
464/**
465 * i915_gem_shrinker_cleanup - Clean up i915 shrinker
466 * @dev_priv: i915 device
467 *
468 * This function unregisters the i915 shrinker and OOM handler.
469 */
470void i915_gem_shrinker_cleanup(struct drm_i915_private *dev_priv)
471{
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);
475}
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