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

1 files changed, 8 insertions, 0 deletions

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index e97eca9..d4f8148 100644
--- a/sys/vm/vm_page.c
+++ b/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;