1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2019 Arm Ltd.
3 *
4 * Based on msm_gem_freedreno.c:
5 * Copyright (C) 2016 Red Hat
6 * Author: Rob Clark <robdclark@gmail.com>
7 */
8
9 #include <linux/list.h>
10
11 #include <drm/drm_device.h>
12 #include <drm/drm_gem_shmem_helper.h>
13
14 #include "panfrost_device.h"
15 #include "panfrost_gem.h"
16 #include "panfrost_mmu.h"
17
18 static unsigned long
panfrost_gem_shrinker_count(struct shrinker * shrinker,struct shrink_control * sc)19 panfrost_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
20 {
21 struct panfrost_device *pfdev =
22 container_of(shrinker, struct panfrost_device, shrinker);
23 struct drm_gem_shmem_object *shmem;
24 unsigned long count = 0;
25
26 if (!mutex_trylock(&pfdev->shrinker_lock))
27 return 0;
28
29 list_for_each_entry(shmem, &pfdev->shrinker_list, madv_list) {
30 if (drm_gem_shmem_is_purgeable(shmem))
31 count += shmem->base.size >> PAGE_SHIFT;
32 }
33
34 mutex_unlock(&pfdev->shrinker_lock);
35
36 return count;
37 }
38
panfrost_gem_purge(struct drm_gem_object * obj)39 static bool panfrost_gem_purge(struct drm_gem_object *obj)
40 {
41 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
42 struct panfrost_gem_object *bo = to_panfrost_bo(obj);
43 bool ret = false;
44
45 if (atomic_read(&bo->gpu_usecount))
46 return false;
47
48 if (!mutex_trylock(&bo->mappings.lock))
49 return false;
50
51 if (!mutex_trylock(&shmem->pages_lock))
52 goto unlock_mappings;
53
54 panfrost_gem_teardown_mappings_locked(bo);
55 drm_gem_shmem_purge_locked(&bo->base);
56 ret = true;
57
58 mutex_unlock(&shmem->pages_lock);
59
60 unlock_mappings:
61 mutex_unlock(&bo->mappings.lock);
62 return ret;
63 }
64
65 static unsigned long
panfrost_gem_shrinker_scan(struct shrinker * shrinker,struct shrink_control * sc)66 panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
67 {
68 struct panfrost_device *pfdev =
69 container_of(shrinker, struct panfrost_device, shrinker);
70 struct drm_gem_shmem_object *shmem, *tmp;
71 unsigned long freed = 0;
72
73 if (!mutex_trylock(&pfdev->shrinker_lock))
74 return SHRINK_STOP;
75
76 list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
77 if (freed >= sc->nr_to_scan)
78 break;
79 if (drm_gem_shmem_is_purgeable(shmem) &&
80 panfrost_gem_purge(&shmem->base)) {
81 freed += shmem->base.size >> PAGE_SHIFT;
82 list_del_init(&shmem->madv_list);
83 }
84 }
85
86 mutex_unlock(&pfdev->shrinker_lock);
87
88 if (freed > 0)
89 pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
90
91 return freed;
92 }
93
94 /**
95 * panfrost_gem_shrinker_init - Initialize panfrost shrinker
96 * @dev: DRM device
97 *
98 * This function registers and sets up the panfrost shrinker.
99 */
panfrost_gem_shrinker_init(struct drm_device * dev)100 void panfrost_gem_shrinker_init(struct drm_device *dev)
101 {
102 struct panfrost_device *pfdev = dev->dev_private;
103 pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
104 pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
105 pfdev->shrinker.seeks = DEFAULT_SEEKS;
106 WARN_ON(register_shrinker(&pfdev->shrinker, "drm-panfrost"));
107 }
108
109 /**
110 * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
111 * @dev: DRM device
112 *
113 * This function unregisters the panfrost shrinker.
114 */
panfrost_gem_shrinker_cleanup(struct drm_device * dev)115 void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
116 {
117 struct panfrost_device *pfdev = dev->dev_private;
118
119 if (pfdev->shrinker.nr_deferred) {
120 unregister_shrinker(&pfdev->shrinker);
121 }
122 }
123