drivers/staging/ramzswap/ramzswap_ioctl.h

/*
 * Compressed RAM based swap device
 *
 * Copyright (C) 2008, 2009, 2010  Nitin Gupta
 *
 * This code is released using a dual license strategy: BSD/GPL
 * You can choose the licence 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
 *
 * Project home: http://compcache.googlecode.com
 */

#ifndef _RAMZSWAP_IOCTL_H_
#define _RAMZSWAP_IOCTL_H_

#define MAX_SWAP_NAME_LEN 128

struct ramzswap_ioctl_stats {
	char backing_swap_name[MAX_SWAP_NAME_LEN];
	u64 memlimit;		/* only applicable if backing swap present */
	u64 disksize;		/* user specified or equal to backing swap
				 * size (if present) */
	u64 num_reads;		/* failed + successful */
	u64 num_writes;		/* --do-- */
	u64 failed_reads;	/* should NEVER! happen */
	u64 failed_writes;	/* can happen when memory is too low */
	u64 invalid_io;		/* non-swap I/O requests */
	u64 notify_free;	/* no. of swap slot free notifications */
	u32 pages_zero;		/* no. of zero filled pages */
	u32 good_compress_pct;	/* no. of pages with compression ratio<=50% */
	u32 pages_expand_pct;	/* no. of incompressible pages */
	u32 pages_stored;
	u32 pages_used;
	u64 orig_data_size;
	u64 compr_data_size;
	u64 mem_used_total;
	u64 bdev_num_reads;	/* no. of reads on backing dev */
	u64 bdev_num_writes;	/* no. of writes on backing dev */
} __attribute__ ((packed, aligned(4)));

#define RZSIO_SET_DISKSIZE_KB	_IOW('z', 0, size_t)
#define RZSIO_SET_MEMLIMIT_KB	_IOW('z', 1, size_t)
#define RZSIO_SET_BACKING_SWAP	_IOW('z', 2, unsigned char[MAX_SWAP_NAME_LEN])
#define RZSIO_GET_STATS		_IOR('z', 3, struct ramzswap_ioctl_stats)
#define RZSIO_INIT		_IO('z', 4)
#define RZSIO_RESET		_IO('z', 5)

#endif