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
18static unsigned long
19panfrost_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
39static 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(obj);
56	ret = true;
57
58	mutex_unlock(&shmem->pages_lock);
59
60unlock_mappings:
61	mutex_unlock(&bo->mappings.lock);
62	return ret;
63}
64
65static unsigned long
66panfrost_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 */
100void 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));
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 */
115void 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