Add support for automatic promotion of 4KB page mappings to 2MB page

mappings.  Automatic promotion can be enabled by setting the tunable
"vm.pmap.pg_ps_enabled" to a non-zero value.  By default, automatic
promotion is disabled.  (Expect this to change.)

Reviewed by:	ups
Tested by:	kris, Peter Holm

1 files changed, 10 insertions, 2 deletions

diff --git a/sys/amd64/include/pmap.h b/sys/amd64/include/pmap.h
index 61c4db6..9844d76 100644
--- a/sys/amd64/include/pmap.h
+++ b/sys/amd64/include/pmap.h
@@ -57,7 +57,7 @@
 #define	PG_NC_PCD	0x010	/* PCD	Cache disable		*/
 #define PG_A		0x020	/* A	Accessed		*/
 #define	PG_M		0x040	/* D	Dirty			*/
-#define	PG_PS		0x080	/* PS	Page size (0=4k,1=4M)	*/
+#define	PG_PS		0x080	/* PS	Page size (0=4k,1=2M)	*/
 #define	PG_PTE_PAT	0x080	/* PAT	PAT index		*/
 #define	PG_G		0x100	/* G	Global			*/
 #define	PG_AVAIL1	0x200	/*    /	Available for system	*/
@@ -76,6 +76,13 @@
 #define PG_N		(PG_NC_PWT|PG_NC_PCD)	/* Non-cacheable */
 
 /*
+ * Promotion to a 2MB (PDE) page mapping requires that the corresponding 4KB
+ * (PTE) page mappings have identical settings for the following fields:
+ */
+#define	PG_PTE_PROMOTE	(PG_NX | PG_MANAGED | PG_W | PG_G | PG_PTE_PAT | \
+	    PG_M | PG_A | PG_NC_PCD | PG_NC_PWT | PG_U | PG_RW | PG_V)
+
+/*
  * Page Protection Exception bits
  */
 
@@ -241,6 +248,7 @@ struct pmap {
 	u_int			pm_active;	/* active on cpus */
 	/* spare u_int here due to padding */
 	struct pmap_statistics	pm_stats;	/* pmap statistics */
+	vm_page_t		pm_root;	/* spare page table pages */
 };
 
 typedef struct pmap	*pmap_t;
@@ -301,7 +309,6 @@ extern vm_paddr_t dump_avail[];
 extern vm_offset_t virtual_avail;
 extern vm_offset_t virtual_end;
 
-#define	pmap_page_is_mapped(m)	(!TAILQ_EMPTY(&(m)->md.pv_list))
 #define	pmap_unmapbios(va, sz)	pmap_unmapdev((va), (sz))
 
 void	pmap_bootstrap(vm_paddr_t *);
@@ -315,6 +322,7 @@ void	pmap_kremove(vm_offset_t);
 void	*pmap_mapbios(vm_paddr_t, vm_size_t);
 void	*pmap_mapdev(vm_paddr_t, vm_size_t);
 void	*pmap_mapdev_attr(vm_paddr_t, vm_size_t, int);
+boolean_t pmap_page_is_mapped(vm_page_t m);
 void	pmap_unmapdev(vm_offset_t, vm_size_t);
 void	pmap_invalidate_page(pmap_t, vm_offset_t);
 void	pmap_invalidate_range(pmap_t, vm_offset_t, vm_offset_t);