aboutsummaryrefslogtreecommitdiff
path: root/drivers/gpu/ion/ion_page_pool.c
blob: d8f3b9e8211de08ad80bcddd7d0852ef2c5d4a56 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
/*
 * drivers/gpu/ion/ion_mem_pool.c
 *
 * Copyright (C) 2011 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/debugfs.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/shrinker.h>
#include "ion_priv.h"

/* #define DEBUG_PAGE_POOL_SHRINKER */

static struct plist_head pools = PLIST_HEAD_INIT(pools);
static struct shrinker shrinker;

struct ion_page_pool_item {
	struct page *page;
	struct list_head list;
};

static void *ion_page_pool_alloc_pages(struct ion_page_pool *pool)
{
	struct page *page = alloc_pages(pool->gfp_mask, pool->order);

	if (!page)
		return NULL;
	/* this is only being used to flush the page for dma,
	   this api is not really suitable for calling from a driver
	   but no better way to flush a page for dma exist at this time */
	arm_dma_ops.sync_single_for_device(NULL,
					   pfn_to_dma(NULL, page_to_pfn(page)),
					   PAGE_SIZE << pool->order,
					   DMA_BIDIRECTIONAL);
	return page;
}

static void ion_page_pool_free_pages(struct ion_page_pool *pool,
				     struct page *page)
{
	__free_pages(page, pool->order);
}

static int ion_page_pool_add(struct ion_page_pool *pool, struct page *page)
{
	struct ion_page_pool_item *item;

	item = kmalloc(sizeof(struct ion_page_pool_item), GFP_KERNEL);
	if (!item)
		return -ENOMEM;

	mutex_lock(&pool->mutex);
	item->page = page;
	if (PageHighMem(page)) {
		list_add_tail(&item->list, &pool->high_items);
		pool->high_count++;
	} else {
		list_add_tail(&item->list, &pool->low_items);
		pool->low_count++;
	}
	mutex_unlock(&pool->mutex);
	return 0;
}

static struct page *ion_page_pool_remove(struct ion_page_pool *pool, bool high)
{
	struct ion_page_pool_item *item;
	struct page *page;

	if (high) {
		BUG_ON(!pool->high_count);
		item = list_first_entry(&pool->high_items,
					struct ion_page_pool_item, list);
		pool->high_count--;
	} else {
		BUG_ON(!pool->low_count);
		item = list_first_entry(&pool->low_items,
					struct ion_page_pool_item, list);
		pool->low_count--;
	}

	list_del(&item->list);
	page = item->page;
	kfree(item);
	return page;
}

void *ion_page_pool_alloc(struct ion_page_pool *pool)
{
	struct page *page = NULL;

	BUG_ON(!pool);

	mutex_lock(&pool->mutex);
	if (pool->high_count)
		page = ion_page_pool_remove(pool, true);
	else if (pool->low_count)
		page = ion_page_pool_remove(pool, false);
	mutex_unlock(&pool->mutex);

	if (!page)
		page = ion_page_pool_alloc_pages(pool);

	return page;
}

void ion_page_pool_free(struct ion_page_pool *pool, struct page* page)
{
	int ret;

	ret = ion_page_pool_add(pool, page);
	if (ret)
		ion_page_pool_free_pages(pool, page);
}

#ifdef DEBUG_PAGE_POOL_SHRINKER
static int debug_drop_pools_set(void *data, u64 val)
{
	struct shrink_control sc;
	int objs;

	sc.gfp_mask = -1;
	sc.nr_to_scan = 0;

	if (!val)
		return 0;

	objs = shrinker.shrink(&shrinker, &sc);
	sc.nr_to_scan = objs;

	shrinker.shrink(&shrinker, &sc);
	return 0;
}

static int debug_drop_pools_get(void *data, u64 *val)
{
	struct shrink_control sc;
	int objs;

	sc.gfp_mask = -1;
	sc.nr_to_scan = 0;

	objs = shrinker.shrink(&shrinker, &sc);
	*val = objs;
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(debug_drop_pools_fops, debug_drop_pools_get,
                        debug_drop_pools_set, "%llu\n");

static int debug_grow_pools_set(void *data, u64 val)
{
	struct ion_page_pool *pool;
	struct page *page;

	plist_for_each_entry(pool, &pools, list) {
		if (val != pool->list.prio)
			continue;
		page = ion_page_pool_alloc_pages(pool);
		if (page)
			ion_page_pool_add(pool, page);
	}

	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(debug_grow_pools_fops, debug_drop_pools_get,
			debug_grow_pools_set, "%llu\n");
#endif

static int ion_page_pool_total(bool high)
{
	struct ion_page_pool *pool;
	int total = 0;

	plist_for_each_entry(pool, &pools, list) {
		total += high ? (pool->high_count + pool->low_count) *
			(1 << pool->order) :
			pool->low_count * (1 << pool->order);
	}
	return total;
}

static int ion_page_pool_shrink(struct shrinker *shrinker,
				 struct shrink_control *sc)
{
	struct ion_page_pool *pool;
	int nr_freed = 0;
	int i;
	bool high;
	int nr_to_scan = sc->nr_to_scan;

	high = sc->gfp_mask & __GFP_HIGHMEM;

	if (nr_to_scan == 0)
		return ion_page_pool_total(high);

	plist_for_each_entry(pool, &pools, list) {
		for (i = 0; i < nr_to_scan; i++) {
			struct page *page;

			mutex_lock(&pool->mutex);
			if (high && pool->high_count) {
				page = ion_page_pool_remove(pool, true);
			} else if (pool->low_count) {
				page = ion_page_pool_remove(pool, false);
			} else {
				mutex_unlock(&pool->mutex);
				break;
			}
			mutex_unlock(&pool->mutex);
			ion_page_pool_free_pages(pool, page);
			nr_freed += (1 << pool->order);
		}
		nr_to_scan -= i;
	}

	return ion_page_pool_total(high);
}

struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order)
{
	struct ion_page_pool *pool = kmalloc(sizeof(struct ion_page_pool),
					     GFP_KERNEL);
	if (!pool)
		return NULL;
	pool->high_count = 0;
	pool->low_count = 0;
	INIT_LIST_HEAD(&pool->low_items);
	INIT_LIST_HEAD(&pool->high_items);
	pool->gfp_mask = gfp_mask;
	pool->order = order;
	mutex_init(&pool->mutex);
	plist_node_init(&pool->list, order);
	plist_add(&pool->list, &pools);

	return pool;
}

void ion_page_pool_destroy(struct ion_page_pool *pool)
{
	plist_del(&pool->list, &pools);
	kfree(pool);
}

static int __init ion_page_pool_init(void)
{
	shrinker.shrink = ion_page_pool_shrink;
	shrinker.seeks = DEFAULT_SEEKS;
	shrinker.batch = 0;
	register_shrinker(&shrinker);
#ifdef DEBUG_PAGE_POOL_SHRINKER
	debugfs_create_file("ion_pools_shrink", 0644, NULL, NULL,
			    &debug_drop_pools_fops);
	debugfs_create_file("ion_pools_grow", 0644, NULL, NULL,
			    &debug_grow_pools_fops);
#endif
	return 0;
}

static void __exit ion_page_pool_exit(void)
{
	unregister_shrinker(&shrinker);
}

module_init(ion_page_pool_init);
module_exit(ion_page_pool_exit);