linux-imx

/*

 * zsmalloc memory allocator

 *

 * Copyright (C) 2011  Nitin Gupta

 * Copyright (C) 2012, 2013 Minchan Kim

 *

 * This code is released using a dual license strategy: BSD/GPL

 * You can choose the license that better fits your requirements.

 *

 * Released under the terms of 3-clause BSD License

 * Released under the terms of GNU General Public License Version 2.0

 */

​

/*

 * Following is how we use various fields and flags of underlying

 * struct page(s) to form a zspage.

 *

 * Usage of struct page fields:

 *  page->private: points to zspage

 *  page->freelist(index): links together all component pages of a zspage

 *      For the huge page, this is always 0, so we use this field

 *      to store handle.

 *  page->units: first object offset in a subpage of zspage

 *

 * Usage of struct page flags:

 *  PG_private: identifies the first component page

 *  PG_owner_priv_1: identifies the huge component page

 *

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/magic.h>

#include <linux/bitops.h>

#include <linux/errno.h>

#include <linux/highmem.h>

#include <linux/string.h>

#include <linux/slab.h>

#include <asm/tlbflush.h>

#include <asm/pgtable.h>

#include <linux/cpumask.h>

#include <linux/cpu.h>

#include <linux/vmalloc.h>

#include <linux/preempt.h>

#include <linux/spinlock.h>

#include <linux/shrinker.h>

#include <linux/types.h>

#include <linux/debugfs.h>

#include <linux/zsmalloc.h>

#include <linux/zpool.h>

#include <linux/mount.h>

#include <linux/migrate.h>

#include <linux/pagemap.h>

#include <linux/fs.h>

​

#define ZSPAGE_MAGIC    0x58

​

/*

 * This must be power of 2 and greater than of equal to sizeof(link_free).

 * These two conditions ensure that any 'struct link_free' itself doesn't

 * span more than 1 page which avoids complex case of mapping 2 pages simply

 * to restore link_free pointer values.

 */

#define ZS_ALIGN        8

​

/*

 * A single 'zspage' is composed of up to 2^N discontiguous 0-order (single)

 * pages. ZS_MAX_ZSPAGE_ORDER defines upper limit on N.

 */

#define ZS_MAX_ZSPAGE_ORDER 2

#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER)

​

#define ZS_HANDLE_SIZE (sizeof(unsigned long))

​

/*

 * Object location (<PFN>, <obj_idx>) is encoded as

 * as single (unsigned long) handle value.

 *

 * Note that object index <obj_idx> starts from 0.

 *

 * This is made more complicated by various memory models and PAE.

 */

​

#ifndef MAX_POSSIBLE_PHYSMEM_BITS

#ifdef MAX_PHYSMEM_BITS

#define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS

#else

/*

 * If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just