diff options
author | rgrimes <rgrimes@FreeBSD.org> | 1994-05-25 09:21:21 +0000 |
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committer | rgrimes <rgrimes@FreeBSD.org> | 1994-05-25 09:21:21 +0000 |
commit | 2469c867a164210ce96143517059f21db7f1fd17 (patch) | |
tree | 9179427ac860211c445df663fd2b86267366bfba /sys/vm/swap_pager.h | |
parent | cb0aba89af15a48e2655e898a503946ac4cb42ae (diff) | |
download | FreeBSD-src-2469c867a164210ce96143517059f21db7f1fd17.zip FreeBSD-src-2469c867a164210ce96143517059f21db7f1fd17.tar.gz |
The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.
Reviewed by: Rodney W. Grimes
Submitted by: John Dyson and David Greenman
Diffstat (limited to 'sys/vm/swap_pager.h')
-rw-r--r-- | sys/vm/swap_pager.h | 65 |
1 files changed, 37 insertions, 28 deletions
diff --git a/sys/vm/swap_pager.h b/sys/vm/swap_pager.h index 497d92a..853edd5 100644 --- a/sys/vm/swap_pager.h +++ b/sys/vm/swap_pager.h @@ -1,7 +1,7 @@ /* * Copyright (c) 1990 University of Utah. - * Copyright (c) 1991, 1993 - * The Regents of the University of California. All rights reserved. + * 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 @@ -35,39 +35,31 @@ * 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 + * from: @(#)swap_pager.h 7.1 (Berkeley) 12/5/90 + * $Id: swap_pager.h,v 1.9 1994/03/14 21:54:23 davidg Exp $ + */ + +/* + * Modifications to the block allocation data structure by John S. Dyson + * 18 Dec 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. + * 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... */ -typedef int sw_bm_t; /* pager bitmask */ - +#define SWB_NPAGES 8 struct swblock { - sw_bm_t swb_mask; /* bitmask of valid pages in this block */ - daddr_t swb_block; /* starting disk block for this block */ + 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; @@ -76,15 +68,32 @@ typedef struct swblock *sw_blk_t; */ 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 */ + 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(); + +extern struct pagerops swappagerops; + +#endif + #endif /* _SWAP_PAGER_ */ |