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
 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
 57static unsigned long
 58panfrost_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 */
 92void 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 */
107void 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}