diff options
Diffstat (limited to 'drivers/staging/android/ion/ion_page_pool.c')
-rw-r--r-- | drivers/staging/android/ion/ion_page_pool.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c new file mode 100644 index 000000000..4b88f11e5 --- /dev/null +++ b/drivers/staging/android/ion/ion_page_pool.c @@ -0,0 +1,182 @@ +/* + * 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/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/swap.h> +#include "ion_priv.h" + +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; + ion_pages_sync_for_device(NULL, 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) +{ + mutex_lock(&pool->mutex); + if (PageHighMem(page)) { + list_add_tail(&page->lru, &pool->high_items); + pool->high_count++; + } else { + list_add_tail(&page->lru, &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 page *page; + + if (high) { + BUG_ON(!pool->high_count); + page = list_first_entry(&pool->high_items, struct page, lru); + pool->high_count--; + } else { + BUG_ON(!pool->low_count); + page = list_first_entry(&pool->low_items, struct page, lru); + pool->low_count--; + } + + list_del(&page->lru); + return page; +} + +struct page *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; + + BUG_ON(pool->order != compound_order(page)); + + ret = ion_page_pool_add(pool, page); + if (ret) + ion_page_pool_free_pages(pool, page); +} + +static int ion_page_pool_total(struct ion_page_pool *pool, bool high) +{ + int count = pool->low_count; + + if (high) + count += pool->high_count; + + return count << pool->order; +} + +int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask, + int nr_to_scan) +{ + int freed; + bool high; + + if (current_is_kswapd()) + high = true; + else + high = !!(gfp_mask & __GFP_HIGHMEM); + + if (nr_to_scan == 0) + return ion_page_pool_total(pool, high); + + for (freed = 0; freed < nr_to_scan; freed++) { + struct page *page; + + mutex_lock(&pool->mutex); + if (pool->low_count) { + page = ion_page_pool_remove(pool, false); + } else if (high && pool->high_count) { + page = ion_page_pool_remove(pool, true); + } else { + mutex_unlock(&pool->mutex); + break; + } + mutex_unlock(&pool->mutex); + ion_page_pool_free_pages(pool, page); + } + + return freed; +} + +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 | __GFP_COMP; + pool->order = order; + mutex_init(&pool->mutex); + plist_node_init(&pool->list, order); + + return pool; +} + +void ion_page_pool_destroy(struct ion_page_pool *pool) +{ + kfree(pool); +} + +static int __init ion_page_pool_init(void) +{ + return 0; +} + +static void __exit ion_page_pool_exit(void) +{ +} + +module_init(ion_page_pool_init); +module_exit(ion_page_pool_exit); |