freebsd-skq/sys/vm/swap_pager.h
dg 1707d41102 These changes embody the support of the fully coherent merged VM buffer cache,
much higher filesystem I/O performance, and much better paging performance. It
represents the culmination of over 6 months of R&D.

The majority of the merged VM/cache work is by John Dyson.

The following highlights the most significant changes. Additionally, there are
(mostly minor) changes to the various filesystem modules (nfs, msdosfs, etc) to
support the new VM/buffer scheme.

vfs_bio.c:
Significant rewrite of most of vfs_bio to support the merged VM buffer cache
scheme.  The scheme is almost fully compatible with the old filesystem
interface.  Significant improvement in the number of opportunities for write
clustering.

vfs_cluster.c, vfs_subr.c
Upgrade and performance enhancements in vfs layer code to support merged
VM/buffer cache.  Fixup of vfs_cluster to eliminate the bogus pagemove stuff.

vm_object.c:
Yet more improvements in the collapse code.  Elimination of some windows that
can cause list corruption.

vm_pageout.c:
Fixed it, it really works better now.  Somehow in 2.0, some "enhancements"
broke the code.  This code has been reworked from the ground-up.

vm_fault.c, vm_page.c, pmap.c, vm_object.c
Support for small-block filesystems with merged VM/buffer cache scheme.

pmap.c vm_map.c
Dynamic kernel VM size, now we dont have to pre-allocate excessive numbers of
kernel PTs.

vm_glue.c
Much simpler and more effective swapping code.  No more gratuitous swapping.

proc.h
Fixed the problem that the p_lock flag was not being cleared on a fork.

swap_pager.c, vnode_pager.c
Removal of old vfs_bio cruft to support the past pseudo-coherency.  Now the
code doesn't need it anymore.

machdep.c
Changes to better support the parameter values for the merged VM/buffer cache
scheme.

machdep.c, kern_exec.c, vm_glue.c
Implemented a seperate submap for temporary exec string space and another one
to contain process upages. This eliminates all map fragmentation problems
that previously existed.

ffs_inode.c, ufs_inode.c, ufs_readwrite.c
Changes for merged VM/buffer cache.  Add "bypass" support for sneaking in on
busy buffers.

Submitted by:	John Dyson and David Greenman
1995-01-09 16:06:02 +00:00

102 lines
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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 1.3 1994/10/09 01:52:06 phk 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 manditory
* 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 */
int swb_block[SWB_NPAGES]; /* unfortunately int instead of daddr_t */
};
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_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 */
short sw_piip; /* pageins in progress */
};
typedef struct swpager *sw_pager_t;
#define SW_WANTED 0x01
#define SW_NAMED 0x02
#ifdef KERNEL
void swap_pager_init(void);
vm_pager_t swap_pager_alloc(caddr_t, vm_size_t, vm_prot_t, vm_offset_t);
void swap_pager_dealloc(vm_pager_t);
boolean_t swap_pager_getpage(vm_pager_t, vm_page_t, boolean_t);
boolean_t swap_pager_putpage(vm_pager_t, vm_page_t, boolean_t);
boolean_t swap_pager_getmulti(vm_pager_t, vm_page_t *, int, int, boolean_t);
boolean_t swap_pager_haspage(vm_pager_t, vm_offset_t);
int swap_pager_io(sw_pager_t, vm_page_t *, int, int, int);
void swap_pager_iodone(struct buf *);
boolean_t swap_pager_clean();
void swap_pager_copy __P((vm_pager_t, vm_offset_t, vm_pager_t, vm_offset_t, vm_offset_t));
void swap_pager_freespace __P((vm_pager_t, vm_offset_t, vm_offset_t));
extern struct pagerops swappagerops;
#endif
#endif /* _SWAP_PAGER_ */