--- /dev/null
+/*
+ * drivers/staging/android/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/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/shrinker.h>
+#include "ion_priv.h"
+
+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;
+ item->page = page;
+ list_add_tail(&item->list, &pool->items);
+ pool->count++;
+ return 0;
+}
+
+static struct page *ion_page_pool_remove(struct ion_page_pool *pool)
+{
+ struct ion_page_pool_item *item;
+ struct page *page;
+
+ BUG_ON(!pool->count);
+ BUG_ON(list_empty(&pool->items));
+
+ item = list_first_entry(&pool->items, struct ion_page_pool_item, list);
+ list_del(&item->list);
+ page = item->page;
+ kfree(item);
+ pool->count--;
+ 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->count)
+ page = ion_page_pool_remove(pool);
+ else
+ page = ion_page_pool_alloc_pages(pool);
+ mutex_unlock(&pool->mutex);
+
+ return page;
+}
+
+void ion_page_pool_free(struct ion_page_pool *pool, struct page* page)
+{
+ int ret;
+
+ mutex_lock(&pool->mutex);
+ ret = ion_page_pool_add(pool, page);
+ if (ret)
+ ion_page_pool_free_pages(pool, page);
+ mutex_unlock(&pool->mutex);
+}
+
+static int ion_page_pool_shrink(struct shrinker *shrinker,
+ struct shrink_control *sc)
+{
+ struct ion_page_pool *pool = container_of(shrinker,
+ struct ion_page_pool,
+ shrinker);
+ int nr_freed = 0;
+ int i;
+
+ if (sc->nr_to_scan == 0)
+ return pool->count * (1 << pool->order);
+
+ mutex_lock(&pool->mutex);
+ for (i = 0; i < sc->nr_to_scan && pool->count; i++) {
+ struct ion_page_pool_item *item;
+ struct page *page;
+
+ item = list_first_entry(&pool->items, struct ion_page_pool_item, list);
+ page = item->page;
+ if (PageHighMem(page) && !(sc->gfp_mask & __GFP_HIGHMEM)) {
+ list_move_tail(&item->list, &pool->items);
+ continue;
+ }
+ BUG_ON(page != ion_page_pool_remove(pool));
+ ion_page_pool_free_pages(pool, page);
+ nr_freed += (1 << pool->order);
+ }
+ pr_info("%s: shrunk page_pool of order %d by %d pages\n", __func__,
+ pool->order, nr_freed);
+ mutex_unlock(&pool->mutex);
+
+ return pool->count * (1 << pool->order);
+}
+
+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->count = 0;
+ INIT_LIST_HEAD(&pool->items);
+ pool->shrinker.shrink = ion_page_pool_shrink;
+ pool->shrinker.seeks = DEFAULT_SEEKS * 16;
+ pool->shrinker.batch = 0;
+ register_shrinker(&pool->shrinker);
+ pool->gfp_mask = gfp_mask;
+ pool->order = order;
+ mutex_init(&pool->mutex);
+
+ return pool;
+}
+
+void ion_page_pool_destroy(struct ion_page_pool *pool)
+{
+ unregister_shrinker(&pool->shrinker);
+ kfree(pool);
+}
+
#include <linux/mutex.h>
#include <linux/rbtree.h>
#include <linux/sched.h>
+#include <linux/shrinker.h>
+#include <linux/types.h>
#include "ion.h"
*/
#define ION_CARVEOUT_ALLOCATE_FAIL -1
+/**
+ * functions for creating and destroying a heap pool -- allows you
+ * to keep a pool of pre allocated memory to use from your heap. Keeping
+ * a pool of memory that is ready for dma, ie any cached mapping have been
+ * invalidated from the cache, provides a significant peformance benefit on
+ * many systems */
+
+/**
+ * struct ion_page_pool - pagepool struct
+ * @count: number of items in the pool
+ * @items: list of items
+ * @shrinker: a shrinker for the items
+ * @mutex: lock protecting this struct and especially the count
+ * item list
+ * @alloc: function to be used to allocate pageory when the pool
+ * is empty
+ * @free: function to be used to free pageory back to the system
+ * when the shrinker fires
+ * @gfp_mask: gfp_mask to use from alloc
+ * @order: order of pages in the pool
+ *
+ * Allows you to keep a pool of pre allocated pages to use from your heap.
+ * Keeping a pool of pages that is ready for dma, ie any cached mapping have
+ * been invalidated from the cache, provides a significant peformance benefit
+ * on many systems
+ */
+struct ion_page_pool {
+ int count;
+ struct list_head items;
+ struct shrinker shrinker;
+ struct mutex mutex;
+ void *(*alloc)(struct ion_page_pool *pool);
+ void (*free)(struct ion_page_pool *pool, struct page *page);
+ gfp_t gfp_mask;
+ unsigned int order;
+};
+
+struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order);
+void ion_page_pool_destroy(struct ion_page_pool *);
+void *ion_page_pool_alloc(struct ion_page_pool *);
+void ion_page_pool_free(struct ion_page_pool *, struct page *);
+
#endif /* _ION_PRIV_H */
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