This commit is meant to solve a couple of VM system problems or

performance issues.

	1) The pmap module has had too many inlines, and so the
	   object file is simply bigger than it needs to be.
	   Some common code is also merged into subroutines.
	2) Removal of some *evil* PHYS_TO_VM_PAGE macro calls.
	   Unfortunately, a few have needed to be added also.
	   The removal caused the need for more vm_page_lookups.
	   I added lookup hints to minimize the need for the
	   page table lookup operations.
	3) Removal of some bogus performance improvements, that
	   mostly made the code more complex (tracking individual
	   page table page updates unnecessarily).  Those improvements
	   actually hurt 386 processors perf (not that people who
	   worry about perf use 386 processors anymore :-)).
	4) Changed pv queue manipulations/structures to be TAILQ's.
	5) The pv queue code has had some performance problems since
	   day one.  Some significant scalability issues are resolved
	   by threading the pv entries from the pmap AND the physical
	   address instead of just the physical address.  This makes
	   certain pmap operations run much faster.  This does
	   not affect most micro-benchmarks, but should help loaded system
	   performance *significantly*.  DG helped and came up with most
	   of the solution for this one.
	6) Most if not all pmap bit operations follow the pattern:
		pmap_test_bit();
		pmap_clear_bit();
	   That made for twice the necessary pv list traversal.   The
	   pmap interface now supports only pmap_tc_bit type operations:
	   pmap_[test/clear]_modified, pmap_[test/clear]_referenced.
	   Additionally, the modified routine now takes a vm_page_t arg
	   instead of a phys address.  This eliminates a PHYS_TO_VM_PAGE
	   operation.
	7) Several rewrites of routines that contain redundant code to
	   use common routines, so that there is a greater likelihood of
	   keeping the cache footprint smaller.

1 files changed, 19 insertions, 6 deletions

diff --git a/sys/i386/include/pmap.h b/sys/i386/include/pmap.h
index dbadf6f..b53db62 100644
--- a/sys/i386/include/pmap.h
+++ b/sys/i386/include/pmap.h
@@ -42,12 +42,13 @@
  *
  *	from: hp300: @(#)pmap.h	7.2 (Berkeley) 12/16/90
  *	from: @(#)pmap.h	7.4 (Berkeley) 5/12/91
- * 	$Id: pmap.h,v 1.39 1996/05/18 03:36:38 dyson Exp $
+ * 	$Id: pmap.h,v 1.40 1996/06/08 11:21:19 bde Exp $
  */
 
 #ifndef _MACHINE_PMAP_H_
 #define	_MACHINE_PMAP_H_
 
+
 /*
  * Page-directory and page-table entires follow this format, with a few
  * of the fields not present here and there, depending on a lot of things.
@@ -113,6 +114,9 @@
 #define ISA_HOLE_LENGTH (0x100000-ISA_HOLE_START)
 
 #ifndef LOCORE
+
+#include <sys/queue.h>
+
 typedef unsigned int *pd_entry_t;
 typedef unsigned int *pt_entry_t;
 
@@ -158,17 +162,24 @@ pmap_kextract(vm_offset_t va)
 }
 #endif
 
+struct vm_page;
+
 /*
  * Pmap stuff
  */
+struct	pv_entry;
+typedef struct {
+	int	pv_list_count;
+	TAILQ_HEAD(,pv_entry)	pv_list;
+} pv_table_t;
 
 struct pmap {
 	pd_entry_t		*pm_pdir;	/* KVA of page directory */
 	vm_object_t		pm_pteobj;	/* Container for pte's */
-	short			pm_dref;	/* page directory ref count */
-	short			pm_count;	/* pmap reference count */
+	pv_table_t		pm_pvlist;	/* list of mappings in pmap */
+	int			pm_count;	/* reference count */
 	struct pmap_statistics	pm_stats;	/* pmap statistics */
-	struct	vm_map		*pm_map;	/* map that owns this pmap */
+	struct	vm_page		*pm_ptphint;	/* pmap ptp hint */
 };
 
 typedef struct pmap	*pmap_t;
@@ -177,14 +188,16 @@ typedef struct pmap	*pmap_t;
 extern pmap_t		kernel_pmap;
 #endif
 
+
 /*
  * For each vm_page_t, there is a list of all currently valid virtual
  * mappings of that page.  An entry is a pv_entry_t, the list is pv_table.
  */
 typedef struct pv_entry {
-	struct pv_entry	*pv_next;	/* next pv_entry */
 	pmap_t		pv_pmap;	/* pmap where mapping lies */
 	vm_offset_t	pv_va;		/* virtual address for mapping */
+	TAILQ_ENTRY(pv_entry)	pv_list;
+	TAILQ_ENTRY(pv_entry)	pv_plist;
 	vm_page_t	pv_ptem;	/* VM page for pte */
 } *pv_entry_t;
 
@@ -200,7 +213,7 @@ extern pt_entry_t *CMAP1;
 extern vm_offset_t avail_end;
 extern vm_offset_t avail_start;
 extern vm_offset_t phys_avail[];
-extern pv_entry_t *pv_table;	/* array of entries, one per page */
+pv_table_t *pv_table;
 extern vm_offset_t virtual_avail;
 extern vm_offset_t virtual_end;