cdacc6ab42
multiplexed underlying swap devices (/dev/drum). The only thing it did was to allow root to open /dev/drum, but not do anything with it. Various utilities used to grovel around in here, but Matt has written a much nicer (and clean) front-end to this for libkvm, and nothing uses the old system any more. The VM system was calling VOP_STRATEGY() on the vp of the first underlying swap device (not the /dev/drum one, the first real device), and using the VOP system to indirectly (and only) call swstrategy() to choose an underlying device and enqueue it on that device. I have changed it to avoid diverting through the VOP system and to call the only possible target directly, saving a little bit of time and some complexity. In all, nothing much changes, except some scaffolding to support the roundabout way of calling swstrategy() is gone. Matt gave me the ok to do this some time ago, and I apologize for taking so long to get around to it.
114 lines
4.3 KiB
C
114 lines
4.3 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
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
/*
|
|
* 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_ */
|