Add configuration knobs for the superpage reservation system. Initially,

the reservation will only be enabled on amd64.

sys/amd64/include/vmparam.h

@@ -131,6 +131,20 @@
  */
 #define	VM_NFREEORDER		13
 
+/*
+ * Enable superpage reservations: 1 level.
+ */
+#ifndef	VM_NRESERVLEVEL
+#define	VM_NRESERVLEVEL		1
+#endif
+
+/*
+ * Level 0 reservations consist of 512 pages.
+ */
+#ifndef	VM_LEVEL_0_ORDER
+#define	VM_LEVEL_0_ORDER	9
+#endif
+
 /*
  * Virtual addresses of things.  Derived from the page directory and
  * page table indexes from pmap.h for precision.

sys/arm/include/vmparam.h

@@ -85,6 +85,13 @@
  */
 #define	VM_NFREEORDER		9
 
+/*
+ * Disable superpage reservations.
+ */
+#ifndef	VM_NRESERVLEVEL
+#define	VM_NRESERVLEVEL		0
+#endif
+
 #define UPT_MAX_ADDRESS		VADDR(UPTPTDI + 3, 0)
 #define UPT_MIN_ADDRESS		VADDR(UPTPTDI, 0)
 

sys/conf/options

@@ -551,6 +551,8 @@ VFS_BIO_DEBUG		opt_global.h
 VM_KMEM_SIZE		opt_vm.h
 VM_KMEM_SIZE_SCALE	opt_vm.h
 VM_KMEM_SIZE_MAX	opt_vm.h
+VM_NRESERVLEVEL		opt_vm.h
+VM_LEVEL_0_ORDER	opt_vm.h
 NO_SWAPPING		opt_vm.h
 MALLOC_MAKE_FAILURES	opt_vm.h
 MALLOC_PROFILE		opt_vm.h

sys/i386/include/vmparam.h

@@ -122,6 +122,25 @@
 #define	VM_NFREEORDER		11
 #endif
 
+/*
+ * Disable superpage reservations.
+ */
+#ifndef	VM_NRESERVLEVEL
+#define	VM_NRESERVLEVEL		0
+#endif
+
+/*
+ * Level 0 reservations consist of 512 pages under PAE and 1024 pages
+ * otherwise.
+ */
+#ifndef	VM_LEVEL_0_ORDER
+#ifdef PAE
+#define	VM_LEVEL_0_ORDER	9
+#else
+#define	VM_LEVEL_0_ORDER	10
+#endif
+#endif
+
 /*
  * Kernel physical load address.
  */

sys/ia64/include/vmparam.h

@@ -144,6 +144,13 @@
  */
 #define	VM_NFREEORDER		16
 
+/*
+ * Disable superpage reservations.
+ */
+#ifndef	VM_NRESERVLEVEL
+#define	VM_NRESERVLEVEL		0
+#endif
+
 /*
  * Manipulating region bits of an address.
  */

sys/powerpc/include/vmparam.h

@@ -131,6 +131,13 @@ struct pmap_physseg {
  */
 #define	VM_NFREEORDER		11
 
+/*
+ * Disable superpage reservations.
+ */
+#ifndef	VM_NRESERVLEVEL
+#define	VM_NRESERVLEVEL		0
+#endif
+
 #ifndef VM_INITIAL_PAGEIN
 #define	VM_INITIAL_PAGEIN	16
 #endif

sys/sparc64/include/vmparam.h

@@ -121,6 +121,13 @@
  */
 #define	VM_NFREEORDER		12
 
+/*
+ * Disable superpage reservations.
+ */
+#ifndef	VM_NRESERVLEVEL
+#define	VM_NRESERVLEVEL		0
+#endif
+
 /*
  * Address space layout.
  *

sys/sun4v/include/vmparam.h

@@ -121,6 +121,13 @@
  */
 #define	VM_NFREEORDER		12
 
+/*
+ * Disable superpage reservations.
+ */
+#ifndef	VM_NRESERVLEVEL
+#define	VM_NRESERVLEVEL		0
+#endif
+
 /*
  * Address space layout.
  *