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 = shrinker->private_data;
 22	struct drm_gem_shmem_object *shmem;
 23	unsigned long count = 0;
 24
 25	if (!mutex_trylock(&pfdev->shrinker_lock))
 26		return 0;
 27
 28	list_for_each_entry(shmem, &pfdev->shrinker_list, madv_list) {
 29		if (drm_gem_shmem_is_purgeable(shmem))
 30			count += shmem->base.size >> PAGE_SHIFT;
 31	}
 32
 33	mutex_unlock(&pfdev->shrinker_lock);
 34
 35	return count;
 36}
 37
 38static bool panfrost_gem_purge(struct drm_gem_object *obj)
 39{
 40	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
 41	struct panfrost_gem_object *bo = to_panfrost_bo(obj);
 42	bool ret = false;
 43
 44	if (atomic_read(&bo->gpu_usecount))
 45		return false;
 46
 47	if (!mutex_trylock(&bo->mappings.lock))
 48		return false;
 49
 50	if (!dma_resv_trylock(shmem->base.resv))
 51		goto unlock_mappings;
 52
 53	panfrost_gem_teardown_mappings_locked(bo);
 54	drm_gem_shmem_purge(&bo->base);
 55	ret = true;
 56
 57	dma_resv_unlock(shmem->base.resv);
 58
 59unlock_mappings:
 60	mutex_unlock(&bo->mappings.lock);
 61	return ret;
 62}
 63
 64static unsigned long
 65panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 66{
 67	struct panfrost_device *pfdev = shrinker->private_data;
 68	struct drm_gem_shmem_object *shmem, *tmp;
 69	unsigned long freed = 0;
 70
 71	if (!mutex_trylock(&pfdev->shrinker_lock))
 72		return SHRINK_STOP;
 73
 74	list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
 75		if (freed >= sc->nr_to_scan)
 76			break;
 77		if (drm_gem_shmem_is_purgeable(shmem) &&
 78		    panfrost_gem_purge(&shmem->base)) {
 79			freed += shmem->base.size >> PAGE_SHIFT;
 80			list_del_init(&shmem->madv_list);
 81		}
 82	}
 83
 84	mutex_unlock(&pfdev->shrinker_lock);
 85
 86	if (freed > 0)
 87		pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
 88
 89	return freed;
 90}
 91
 92/**
 93 * panfrost_gem_shrinker_init - Initialize panfrost shrinker
 94 * @dev: DRM device
 95 *
 96 * This function registers and sets up the panfrost shrinker.
 97 */
 98int panfrost_gem_shrinker_init(struct drm_device *dev)
 99{
100	struct panfrost_device *pfdev = dev->dev_private;
101
102	pfdev->shrinker = shrinker_alloc(0, "drm-panfrost");
103	if (!pfdev->shrinker)
104		return -ENOMEM;
105
106	pfdev->shrinker->count_objects = panfrost_gem_shrinker_count;
107	pfdev->shrinker->scan_objects = panfrost_gem_shrinker_scan;
108	pfdev->shrinker->private_data = pfdev;
109
110	shrinker_register(pfdev->shrinker);
111
112	return 0;
113}
114
115/**
116 * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
117 * @dev: DRM device
118 *
119 * This function unregisters the panfrost shrinker.
120 */
121void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
122{
123	struct panfrost_device *pfdev = dev->dev_private;
124
125	if (pfdev->shrinker)
126		shrinker_free(pfdev->shrinker);
127}