Define every architecture as either VM_PHYSSEG_DENSE or

VM_PHYSSEG_SPARSE depending on whether the physical address space is
densely or sparsely populated with memory.  The effect of this
definition is to determine which of two implementations of
vm_page_array and PHYS_TO_VM_PAGE() is used.  The legacy
implementation is obtained by defining VM_PHYSSEG_DENSE, and a new
implementation that trades off time for space is obtained by defining
VM_PHYSSEG_SPARSE.  For now, all architectures except for ia64 and
sparc64 define VM_PHYSSEG_DENSE.  Defining VM_PHYSSEG_SPARSE on ia64
allows the entirety of my Itanium 2's memory to be used.  Previously,
only the first 1 GB could be used.  Defining VM_PHYSSEG_SPARSE on
sparc64 allows USIIIi-based systems to boot without crashing.

This change is a combination of Nathan Whitehorn's patch and my own
work in perforce.

Discussed with: kmacy, marius, Nathan Whitehorn
PR:		112194

sys/amd64/include/vmparam.h

@@ -87,6 +87,11 @@
  */
 #define	UMA_MD_SMALL_ALLOC
 
+/*
+ * The physical address space is densely populated.
+ */
+#define	VM_PHYSSEG_DENSE
+
 /*
  * Virtual addresses of things.  Derived from the page directory and
  * page table indexes from pmap.h for precision.

sys/arm/include/vmparam.h

@@ -72,6 +72,11 @@
 
 #define	VM_PHYSSEG_NOADD
 
+/*
+ * The physical address space is densely populated.
+ */
+#define	VM_PHYSSEG_DENSE
+
 /*
  * we support 2 free lists:
  *

sys/i386/include/vmparam.h

@@ -81,6 +81,11 @@
 #define	MAXSLP 		20
 
 
+/*
+ * The physical address space is densely populated.
+ */
+#define	VM_PHYSSEG_DENSE
+
 /*
  * Kernel physical load address.
  */

sys/ia64/ia64/machdep.c

@@ -701,21 +701,6 @@ ia64_init(void)
 		if (md->md_type != EFI_MD_TYPE_FREE)
 			continue;
 
-		/*
-		 * Wimp out for now since we do not DTRT here with
-		 * pci bus mastering (no bounce buffering, for example).
-		 */
-		if (pfn0 >= ia64_btop(0x100000000UL)) {
-			printf("Skipping memory chunk start 0x%lx\n",
-			    md->md_phys);
-			continue;
-		}
-		if (pfn1 >= ia64_btop(0x100000000UL)) {
-			printf("Skipping memory chunk end 0x%lx\n",
-			    md->md_phys + md->md_pages * 4096);
-			continue;
-		}
-
 		/*
 		 * We have a memory descriptor that describes conventional
 		 * memory that is for general use. We must determine if the

sys/ia64/include/vmparam.h

@@ -112,6 +112,11 @@
  */
 #define UMA_MD_SMALL_ALLOC
 
+/*
+ * The physical address space is sparsely populated.
+ */
+#define	VM_PHYSSEG_SPARSE
+
 /*
  * Manipulating region bits of an address.
  */

sys/powerpc/include/vmparam.h

@@ -107,6 +107,11 @@ struct pmap_physseg {
 #define	VM_PHYSSEG_STRAT	VM_PSTRAT_BSEARCH
 #define	VM_PHYSSEG_NOADD		/* can't add RAM after vm_mem_init */
 
+/*
+ * The physical address space is densely populated.
+ */
+#define	VM_PHYSSEG_DENSE
+
 #define	VM_NFREELIST		1
 #define	VM_FREELIST_DEFAULT	0
 

sys/sparc64/include/vmparam.h

@@ -77,6 +77,11 @@
  */
 #define	MAXSLP			20
 
+/*
+ * The physical address space is sparsely populated.
+ */
+#define	VM_PHYSSEG_SPARSE
+
 /*
  * Address space layout.
  *

sys/sun4v/include/vmparam.h

@@ -77,6 +77,11 @@
  */
 #define	MAXSLP			20
 
+/*
+ * The physical address space is densely populated.
+ */
+#define	VM_PHYSSEG_DENSE
+
 /*
  * Address space layout.
  *

sys/vm/vm_page.c

@@ -298,7 +298,15 @@ vm_page_startup(vm_offset_t vaddr)
 	 * page).
 	 */
 	first_page = low_water / PAGE_SIZE;
+#ifdef VM_PHYSSEG_SPARSE
+	page_range = 0;
+	for (i = 0; phys_avail[i + 1] != 0; i += 2)
+		page_range += atop(phys_avail[i + 1] - phys_avail[i]);
+#elif defined(VM_PHYSSEG_DENSE)
 	page_range = high_water / PAGE_SIZE - first_page;
+#else
+#error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
+#endif
 	npages = (total - (page_range * sizeof(struct vm_page)) -
 	    (end - new_end)) / PAGE_SIZE;
 	end = new_end;

sys/vm/vm_page.h

@@ -240,6 +240,9 @@ extern struct pq_coloring page_queue_coloring;
 #define ACT_MAX			64
 
 #ifdef _KERNEL
+
+#include <vm/vm_param.h>
+
 /*
  * Each pageable resident page falls into one of four lists:
  *
@@ -275,8 +278,23 @@ extern long first_page;			/* first physical page number */
 
 #define VM_PAGE_TO_PHYS(entry)	((entry)->phys_addr)
 
-#define PHYS_TO_VM_PAGE(pa) \
-		(&vm_page_array[atop(pa) - first_page ])
+static __inline vm_page_t PHYS_TO_VM_PAGE(vm_paddr_t pa);
+
+static __inline vm_page_t
+PHYS_TO_VM_PAGE(vm_paddr_t pa)
+{
+#ifdef VM_PHYSSEG_SPARSE
+	int i, j = 0;
+
+	for (i = 0; phys_avail[i + 1] <= pa || phys_avail[i] > pa; i += 2)
+		j += atop(phys_avail[i + 1] - phys_avail[i]);
+	return (&vm_page_array[j + atop(pa - phys_avail[i])]);
+#elif defined(VM_PHYSSEG_DENSE)
+	return (&vm_page_array[atop(pa) - first_page]);
+#else
+#error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
+#endif
+}
 
 extern struct mtx vm_page_queue_mtx;
 #define vm_page_lock_queues()   mtx_lock(&vm_page_queue_mtx)