/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* ION Page Pool kernel interface header
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*
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* Copyright (C) 2011 Google, Inc.
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*/
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#ifndef _ION_PAGE_POOL_H
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#define _ION_PAGE_POOL_H
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#include <linux/mm_types.h>
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#include <linux/mutex.h>
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#include <linux/shrinker.h>
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#include <linux/types.h>
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/**
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* functions for creating and destroying a heap pool -- allows you
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* to keep a pool of pre allocated memory to use from your heap. Keeping
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* a pool of memory that is ready for dma, ie any cached mapping have been
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* invalidated from the cache, provides a significant performance benefit on
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* many systems
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*/
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/**
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* struct ion_page_pool - pagepool struct
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* @high_count: number of highmem items in the pool
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* @low_count: number of lowmem items in the pool
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* @high_items: list of highmem items
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* @low_items: list of lowmem items
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* @mutex: lock protecting this struct and especially the count
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* item list
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* @gfp_mask: gfp_mask to use from alloc
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* @order: order of pages in the pool
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* @list: plist node for list of pools
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*
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* Allows you to keep a pool of pre allocated pages to use from your heap.
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* Keeping a pool of pages that is ready for dma, ie any cached mapping have
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* been invalidated from the cache, provides a significant performance benefit
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* on many systems
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*/
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struct ion_page_pool {
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int high_count;
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int low_count;
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struct list_head high_items;
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struct list_head low_items;
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struct mutex mutex;
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gfp_t gfp_mask;
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unsigned int order;
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struct plist_node list;
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};
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struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order);
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void ion_page_pool_destroy(struct ion_page_pool *pool);
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struct page *ion_page_pool_alloc(struct ion_page_pool *pool);
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void ion_page_pool_free(struct ion_page_pool *pool, struct page *page);
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int ion_page_pool_nr_pages(struct ion_page_pool *pool);
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/** ion_page_pool_shrink - shrinks the size of the memory cached in the pool
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* @pool: the pool
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* @gfp_mask: the memory type to reclaim
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* @nr_to_scan: number of items to shrink in pages
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*
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* returns the number of items freed in pages
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*/
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int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
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int nr_to_scan);
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#endif /* _ION_PAGE_POOL_H */
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