The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.

Reviewed by:	Rodney W. Grimes
Submitted by:	John Dyson and David Greenman

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_ */