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 (atomic_read(&bo->gpu_usecount))
45 		return false;
46 
47 	if (!mutex_trylock(&shmem->pages_lock))
48 		return false;
49 
50 	panfrost_gem_teardown_mappings(bo);
51 	drm_gem_shmem_purge_locked(obj);
52 
53 	mutex_unlock(&shmem->pages_lock);
54 	return true;
55 }
56 
57 static unsigned long
58 panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
59 {
60 	struct panfrost_device *pfdev =
61 		container_of(shrinker, struct panfrost_device, shrinker);
62 	struct drm_gem_shmem_object *shmem, *tmp;
63 	unsigned long freed = 0;
64 
65 	if (!mutex_trylock(&pfdev->shrinker_lock))
66 		return SHRINK_STOP;
67 
68 	list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
69 		if (freed >= sc->nr_to_scan)
70 			break;
71 		if (drm_gem_shmem_is_purgeable(shmem) &&
72 		    panfrost_gem_purge(&shmem->base)) {
73 			freed += shmem->base.size >> PAGE_SHIFT;
74 			list_del_init(&shmem->madv_list);
75 		}
76 	}
77 
78 	mutex_unlock(&pfdev->shrinker_lock);
79 
80 	if (freed > 0)
81 		pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
82 
83 	return freed;
84 }
85 
86 /**
87  * panfrost_gem_shrinker_init - Initialize panfrost shrinker
88  * @dev: DRM device
89  *
90  * This function registers and sets up the panfrost shrinker.
91  */
92 void panfrost_gem_shrinker_init(struct drm_device *dev)
93 {
94 	struct panfrost_device *pfdev = dev->dev_private;
95 	pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
96 	pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
97 	pfdev->shrinker.seeks = DEFAULT_SEEKS;
98 	WARN_ON(register_shrinker(&pfdev->shrinker));
99 }
100 
101 /**
102  * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
103  * @dev: DRM device
104  *
105  * This function unregisters the panfrost shrinker.
106  */
107 void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
108 {
109 	struct panfrost_device *pfdev = dev->dev_private;
110 
111 	if (pfdev->shrinker.nr_deferred) {
112 		unregister_shrinker(&pfdev->shrinker);
113 	}
114 }
115