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freebsd/sys/vm/swap_pager.h
John Dyson 0a47b48b9f Initial support for MADV_FREE, support for pages that we don't care
about the contents anymore.  This gives us alot of the advantage of
freeing individual pages through munmap, but with almost none of the
overhead.
1996-05-23 00:45:58 +00:00

81 lines
3.4 KiB
C

/*
* Copyright (c) 1990 University of Utah.
* Copyright (c) 1991 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.
*
* from: @(#)swap_pager.h 7.1 (Berkeley) 12/5/90
* $Id: swap_pager.h,v 1.15 1996/03/03 21:11:06 dyson Exp $
*/
/*
* Modifications to the block allocation data structure by John S. Dyson
* 18 Dec 93.
*/
#ifndef _SWAP_PAGER_
#define _SWAP_PAGER_ 1
/*
* SWB_NPAGES can be set to any value from 1 to 16 pages per allocation,
* however, due to the allocation spilling into non-swap pager backed memory,
* suggest keeping SWB_NPAGES small (1-4). If high performance is mandatory
* perhaps up to 8 pages might be in order????
* Above problem has been fixed, now we support 16 pages per block. Unused
* space is recovered by the swap pager now...
*/
#define SWB_NPAGES 8
struct swblock {
unsigned short swb_valid; /* bitmask for valid pages */
unsigned short swb_locked; /* block locked */
daddr_t swb_block[SWB_NPAGES]; /* unfortunately int instead of daddr_t */
};
typedef struct swblock *sw_blk_t;
#ifdef KERNEL
extern struct pagerlst swap_pager_un_object_list;
extern int swap_pager_full;
extern struct rlisthdr swaplist;
int swap_pager_putpages __P((vm_object_t, vm_page_t *, int, boolean_t, int *));
int swap_pager_swp_alloc __P((vm_object_t, int));
void swap_pager_copy __P((vm_object_t, vm_pindex_t, vm_object_t,
vm_pindex_t, vm_pindex_t));
void swap_pager_freespace __P((vm_object_t, vm_pindex_t, vm_size_t));
void swap_pager_dmzspace __P((vm_object_t, vm_pindex_t, vm_size_t));
void swap_pager_swap_init __P((void));
#endif
#endif /* _SWAP_PAGER_ */