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/*
* 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
* $FreeBSD$
*/
/*
* 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...
*/
#if !defined(SWB_NPAGES)
#define SWB_NPAGES 8
#endif
/*
* Piecemeal swap metadata structure. Swap is stored in a radix tree.
*
* If SWB_NPAGES is 8 and sizeof(char *) == sizeof(daddr_t), our radix
* is basically 8. Assuming PAGE_SIZE == 4096, one tree level represents
* 32K worth of data, two levels represent 256K, three levels represent
* 2 MBytes. This is acceptable.
*
* Overall memory utilization is about the same as the old swap structure.
*/
#define SWCORRECT(n) (sizeof(void *) * (n) / sizeof(daddr_t))
#define SWAP_META_PAGES (SWB_NPAGES * 2)
#define SWAP_META_MASK (SWAP_META_PAGES - 1)
struct swblock {
struct swblock *swb_hnext;
vm_object_t swb_object;
vm_pindex_t swb_index;
int swb_count;
daddr_t swb_pages[SWAP_META_PAGES];
};
#ifdef _KERNEL
extern struct pagerlst swap_pager_un_object_list;
extern int swap_pager_full;
extern struct blist *swapblist;
void swap_pager_putpages __P((vm_object_t, vm_page_t *, int, boolean_t, int *));
boolean_t swap_pager_haspage __P((vm_object_t object, vm_pindex_t pindex, int *before, int *after));
int swap_pager_swp_alloc __P((vm_object_t, int));
void swap_pager_copy __P((vm_object_t, vm_object_t, vm_pindex_t, int));
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));
int swap_pager_reserve __P((vm_object_t, vm_pindex_t, vm_size_t));
/*
* newswap functions
*/
void swap_pager_page_removed __P((vm_page_t, vm_object_t));
/* choose underlying swap device and queue up I/O */
struct buf;
void swstrategy __P((struct buf *bp)); /* probably needs to move elsewhere */
#endif
#endif /* _SWAP_PAGER_ */
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