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
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 
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 
44 	if (!mutex_trylock(&shmem->pages_lock))
45 		return false;
46 
47 	panfrost_gem_teardown_mappings(bo);
48 	drm_gem_shmem_purge_locked(obj);
49 
50 	mutex_unlock(&shmem->pages_lock);
51 	return true;
52 }
53 
54 static unsigned long
55 panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
56 {
57 	struct panfrost_device *pfdev =
58 		container_of(shrinker, struct panfrost_device, shrinker);
59 	struct drm_gem_shmem_object *shmem, *tmp;
60 	unsigned long freed = 0;
61 
62 	if (!mutex_trylock(&pfdev->shrinker_lock))
63 		return SHRINK_STOP;
64 
65 	list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
66 		if (freed >= sc->nr_to_scan)
67 			break;
68 		if (drm_gem_shmem_is_purgeable(shmem) &&
69 		    panfrost_gem_purge(&shmem->base)) {
70 			freed += shmem->base.size >> PAGE_SHIFT;
71 			list_del_init(&shmem->madv_list);
72 		}
73 	}
74 
75 	mutex_unlock(&pfdev->shrinker_lock);
76 
77 	if (freed > 0)
78 		pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
79 
80 	return freed;
81 }
82 
83 /**
84  * panfrost_gem_shrinker_init - Initialize panfrost shrinker
85  * @dev: DRM device
86  *
87  * This function registers and sets up the panfrost shrinker.
88  */
89 void panfrost_gem_shrinker_init(struct drm_device *dev)
90 {
91 	struct panfrost_device *pfdev = dev->dev_private;
92 	pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
93 	pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
94 	pfdev->shrinker.seeks = DEFAULT_SEEKS;
95 	WARN_ON(register_shrinker(&pfdev->shrinker));
96 }
97 
98 /**
99  * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
100  * @dev: DRM device
101  *
102  * This function unregisters the panfrost shrinker.
103  */
104 void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
105 {
106 	struct panfrost_device *pfdev = dev->dev_private;
107 
108 	if (pfdev->shrinker.nr_deferred) {
109 		unregister_shrinker(&pfdev->shrinker);
110 	}
111 }
112