1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/gpu/ion/ion_page_pool.c b/drivers/gpu/ion/ion_page_pool.c
new file mode 100644
index 00000000..cd57b30e
--- /dev/null
+++ b/drivers/gpu/ion/ion_page_pool.c
@@ -0,0 +1,281 @@
+/*
+ * 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 */
+	__dma_page_cpu_to_dev(page, 0, 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;
+
+	if (sc->gfp_mask & __GFP_HIGHMEM)
+		high = true;
+
+	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);