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Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2016 Red Hat
4 * Author: Rob Clark <robdclark@gmail.com>
5 */
6
7#include "msm_drv.h"
8#include "msm_gem.h"
9
10static bool msm_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
11{
12 /* NOTE: we are *closer* to being able to get rid of
13 * mutex_trylock_recursive().. the msm_gem code itself does
14 * not need struct_mutex, although codepaths that can trigger
15 * shrinker are still called in code-paths that hold the
16 * struct_mutex.
17 *
18 * Also, msm_obj->madv is protected by struct_mutex.
19 *
20 * The next step is probably split out a seperate lock for
21 * protecting inactive_list, so that shrinker does not need
22 * struct_mutex.
23 */
24 switch (mutex_trylock_recursive(&dev->struct_mutex)) {
25 case MUTEX_TRYLOCK_FAILED:
26 return false;
27
28 case MUTEX_TRYLOCK_SUCCESS:
29 *unlock = true;
30 return true;
31
32 case MUTEX_TRYLOCK_RECURSIVE:
33 *unlock = false;
34 return true;
35 }
36
37 BUG();
38}
39
40static unsigned long
41msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
42{
43 struct msm_drm_private *priv =
44 container_of(shrinker, struct msm_drm_private, shrinker);
45 struct drm_device *dev = priv->dev;
46 struct msm_gem_object *msm_obj;
47 unsigned long count = 0;
48 bool unlock;
49
50 if (!msm_gem_shrinker_lock(dev, &unlock))
51 return 0;
52
53 list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
54 if (is_purgeable(msm_obj))
55 count += msm_obj->base.size >> PAGE_SHIFT;
56 }
57
58 if (unlock)
59 mutex_unlock(&dev->struct_mutex);
60
61 return count;
62}
63
64static unsigned long
65msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
66{
67 struct msm_drm_private *priv =
68 container_of(shrinker, struct msm_drm_private, shrinker);
69 struct drm_device *dev = priv->dev;
70 struct msm_gem_object *msm_obj;
71 unsigned long freed = 0;
72 bool unlock;
73
74 if (!msm_gem_shrinker_lock(dev, &unlock))
75 return SHRINK_STOP;
76
77 list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
78 if (freed >= sc->nr_to_scan)
79 break;
80 if (is_purgeable(msm_obj)) {
81 msm_gem_purge(&msm_obj->base, OBJ_LOCK_SHRINKER);
82 freed += msm_obj->base.size >> PAGE_SHIFT;
83 }
84 }
85
86 if (unlock)
87 mutex_unlock(&dev->struct_mutex);
88
89 if (freed > 0)
90 pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
91
92 return freed;
93}
94
95static int
96msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
97{
98 struct msm_drm_private *priv =
99 container_of(nb, struct msm_drm_private, vmap_notifier);
100 struct drm_device *dev = priv->dev;
101 struct msm_gem_object *msm_obj;
102 unsigned unmapped = 0;
103 bool unlock;
104
105 if (!msm_gem_shrinker_lock(dev, &unlock))
106 return NOTIFY_DONE;
107
108 list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
109 if (is_vunmapable(msm_obj)) {
110 msm_gem_vunmap(&msm_obj->base, OBJ_LOCK_SHRINKER);
111 /* since we don't know any better, lets bail after a few
112 * and if necessary the shrinker will be invoked again.
113 * Seems better than unmapping *everything*
114 */
115 if (++unmapped >= 15)
116 break;
117 }
118 }
119
120 if (unlock)
121 mutex_unlock(&dev->struct_mutex);
122
123 *(unsigned long *)ptr += unmapped;
124
125 if (unmapped > 0)
126 pr_info_ratelimited("Purging %u vmaps\n", unmapped);
127
128 return NOTIFY_DONE;
129}
130
131/**
132 * msm_gem_shrinker_init - Initialize msm shrinker
133 * @dev_priv: msm device
134 *
135 * This function registers and sets up the msm shrinker.
136 */
137void msm_gem_shrinker_init(struct drm_device *dev)
138{
139 struct msm_drm_private *priv = dev->dev_private;
140 priv->shrinker.count_objects = msm_gem_shrinker_count;
141 priv->shrinker.scan_objects = msm_gem_shrinker_scan;
142 priv->shrinker.seeks = DEFAULT_SEEKS;
143 WARN_ON(register_shrinker(&priv->shrinker));
144
145 priv->vmap_notifier.notifier_call = msm_gem_shrinker_vmap;
146 WARN_ON(register_vmap_purge_notifier(&priv->vmap_notifier));
147}
148
149/**
150 * msm_gem_shrinker_cleanup - Clean up msm shrinker
151 * @dev_priv: msm device
152 *
153 * This function unregisters the msm shrinker.
154 */
155void msm_gem_shrinker_cleanup(struct drm_device *dev)
156{
157 struct msm_drm_private *priv = dev->dev_private;
158
159 if (priv->shrinker.nr_deferred) {
160 WARN_ON(unregister_vmap_purge_notifier(&priv->vmap_notifier));
161 unregister_shrinker(&priv->shrinker);
162 }
163}