diff --git a/sys/vm/vm_phys.c b/sys/vm/vm_phys.c
--- a/sys/vm/vm_phys.c
+++ b/sys/vm/vm_phys.c
@@ -107,6 +107,11 @@
 static struct rwlock_padalign vm_phys_fictitious_reg_lock;
 MALLOC_DEFINE(M_FICT_PAGES, "vm_fictitious", "Fictitious VM pages");
 
+struct vm_phys_info {
+	uint64_t free_pages;
+	uint64_t free_blocks;
+};
+
 static struct vm_freelist __aligned(CACHE_LINE_SIZE)
     vm_phys_free_queues[MAXMEMDOM][VM_NFREELIST][VM_NFREEPOOL]
     [VM_NFREEORDER_MAX];
@@ -156,6 +161,11 @@
     sysctl_vm_phys_free, "A",
     "Phys Free Info");
 
+static int sysctl_vm_phys_frag_idx(SYSCTL_HANDLER_ARGS);
+SYSCTL_OID(_vm, OID_AUTO, phys_frag_idx,
+    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
+    sysctl_vm_phys_frag_idx, "A", "Phys Frag Info");
+
 static int sysctl_vm_phys_segs(SYSCTL_HANDLER_ARGS);
 SYSCTL_OID(_vm, OID_AUTO, phys_segs,
     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
@@ -291,6 +301,78 @@
 	return (error);
 }
 
+static void
+vm_phys_get_info(struct vm_phys_info *info, int domain)
+{
+	struct vm_freelist *fl;
+	int pind, oind, flind;
+
+	/* Calculate total number of free pages and blocks */
+	info->free_pages = info->free_blocks = 0;
+	for (flind = 0; flind < vm_nfreelists; flind++) {
+		for (oind = VM_NFREEORDER - 1; oind >= 0; oind--) {
+			for (pind = 0; pind < VM_NFREEPOOL; pind++) {
+				fl = vm_phys_free_queues[domain][flind][pind];
+				info->free_pages += fl[oind].lcnt << oind;
+				info->free_blocks += fl[oind].lcnt;
+			}
+		}
+	}
+}
+
+static int
+vm_phys_fragmentation_index(int order, int domain)
+{
+	struct vm_phys_info info;
+
+	vm_domain_free_assert_locked(VM_DOMAIN(domain));
+	vm_phys_get_info(&info, domain);
+
+	if (info.free_blocks == 0) {
+		return (0);
+	}
+
+	return (1000 -
+	    ((info.free_pages * 1000) / (1 << order) / info.free_blocks));
+}
+
+/*
+ * Outputs the value of the Free Memory Fragmentation Index (FMFI) for each
+ * domain.
+ */
+static int
+sysctl_vm_phys_frag_idx(SYSCTL_HANDLER_ARGS)
+{
+	struct sbuf sbuf;
+	int64_t idx;
+	int oind, dom, error;
+
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error != 0)
+		return (error);
+	sbuf_new_for_sysctl(&sbuf, NULL, 128 * vm_ndomains, req);
+
+	for (dom = 0; dom < vm_ndomains; dom++) {
+
+		sbuf_printf(&sbuf, "\nDOMAIN %d\n", dom);
+		sbuf_printf(&sbuf, "\n  ORDER (SIZE) |  FMFI\n");
+		sbuf_printf(&sbuf, "--\n");
+
+		vm_domain_free_lock(VM_DOMAIN(dom));
+		for (oind = VM_NFREEORDER - 1; oind >= 0; oind--) {
+			idx = vm_phys_fragmentation_index(oind, dom);
+			sbuf_printf(&sbuf, "  %2d (%6dK) ", oind,
+			    1 << (PAGE_SHIFT - 10 + oind));
+			sbuf_printf(&sbuf, "|  %ld \n", idx);
+		}
+		vm_domain_free_unlock(VM_DOMAIN(dom));
+	}
+
+	error = sbuf_finish(&sbuf);
+	sbuf_delete(&sbuf);
+	return (error);
+}
+
 /*
  * Outputs the set of physical memory segments.
  */