mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-17 10:26:15 +00:00
91 lines
3.8 KiB
C
91 lines
3.8 KiB
C
/*
|
|
* Copyright (c) 1990 University of Utah.
|
|
* Copyright (c) 1991, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* the Systems Programming Group of the University of Utah Computer
|
|
* Science Department.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* @(#)swap_pager.h 8.1 (Berkeley) 6/11/93
|
|
*/
|
|
|
|
#ifndef _SWAP_PAGER_
|
|
#define _SWAP_PAGER_ 1
|
|
|
|
/*
|
|
* In the swap pager, the backing store for an object is organized as an
|
|
* array of some number of "swap blocks". A swap block consists of a bitmask
|
|
* and some number of contiguous DEV_BSIZE disk blocks. The minimum size
|
|
* of a swap block is:
|
|
*
|
|
* max(PAGE_SIZE, dmmin*DEV_BSIZE) [ 32k currently ]
|
|
*
|
|
* bytes (since the pager interface is page oriented), the maximum size is:
|
|
*
|
|
* min(#bits(swb_mask)*PAGE_SIZE, dmmax*DEV_BSIZE) [ 128k currently ]
|
|
*
|
|
* where dmmin and dmmax are left over from the old VM interface. The bitmask
|
|
* (swb_mask) is used by swap_pager_haspage() to determine if a particular
|
|
* page has actually been written; i.e. the pager copy of the page is valid.
|
|
* All swap blocks in the backing store of an object will be the same size.
|
|
*
|
|
* The reason for variable sized swap blocks is to reduce fragmentation of
|
|
* swap resources. Whenever possible we allocate smaller swap blocks to
|
|
* smaller objects. The swap block size is determined from a table of
|
|
* object-size vs. swap-block-size computed at boot time.
|
|
*/
|
|
typedef int sw_bm_t; /* pager bitmask */
|
|
|
|
struct swblock {
|
|
sw_bm_t swb_mask; /* bitmask of valid pages in this block */
|
|
daddr_t swb_block; /* starting disk block for this block */
|
|
};
|
|
typedef struct swblock *sw_blk_t;
|
|
|
|
/*
|
|
* Swap pager private data.
|
|
*/
|
|
struct swpager {
|
|
vm_size_t sw_osize; /* size of object we are backing (bytes) */
|
|
int sw_bsize; /* size of swap blocks (DEV_BSIZE units) */
|
|
int sw_nblocks;/* number of blocks in list (sw_blk_t units) */
|
|
sw_blk_t sw_blocks; /* pointer to list of swap blocks */
|
|
short sw_flags; /* flags */
|
|
short sw_poip; /* pageouts in progress */
|
|
};
|
|
typedef struct swpager *sw_pager_t;
|
|
|
|
#define SW_WANTED 0x01
|
|
#define SW_NAMED 0x02
|
|
|
|
#endif /* _SWAP_PAGER_ */
|