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(&bo->base);
 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, "drm-panfrost"));
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}