diff --git a/src/alloc-override.c b/src/alloc-override.c
index f97b6e78..af9035dd 100644
--- a/src/alloc-override.c
+++ b/src/alloc-override.c
@@ -173,7 +173,7 @@ extern "C" {
 void   cfree(void* p)                    MI_FORWARD0(mi_free, p)
 void*  reallocf(void* p, size_t newsize) MI_FORWARD2(mi_reallocf,p,newsize)
 size_t malloc_size(const void* p)        MI_FORWARD1(mi_usable_size,p)
-#if !defined(__ANDROID__)
+#if !defined(__ANDROID__) && !defined(__FreeBSD__)
 size_t malloc_usable_size(void *p)       MI_FORWARD1(mi_usable_size,p)
 #else
 size_t malloc_usable_size(const void *p) MI_FORWARD1(mi_usable_size,p)
diff --git a/src/os.c b/src/os.c
index e40d57a9..4b4dfe5a 100644
--- a/src/os.c
+++ b/src/os.c
@@ -53,7 +53,12 @@ terms of the MIT license. A copy of the license can be found in the file
 #include <mach/vm_statistics.h>
 #endif
 #endif
-#if defined(__FreeBSD__)
+#if defined(__FreeBSD__) || defined(__DragonFly__)
+#include <sys/param.h>
+#if __FreeBSD_version >= 1200000
+#include <sys/cpuset.h>
+#include <sys/domainset.h>
+#endif
 #include <sys/sysctl.h>
 #endif
 #endif
@@ -1272,6 +1277,47 @@ static size_t mi_os_numa_node_countx(void) {
   }
   return (node+1);
 }
+#elif defined(__FreeBSD__) && __FreeBSD_version >= 1200000
+static size_t mi_os_numa_nodex(void) {
+  domainset_t dom;
+  size_t node;
+  int policy;
+
+  if (cpuset_getdomain(CPU_LEVEL_CPUSET, CPU_WHICH_PID, -1, sizeof(dom), &dom, &policy) == -1) return 0ul;
+
+  for (node = 0; node < MAXMEMDOM; node++) {
+      if (DOMAINSET_ISSET(node, &dom)) return node;
+  }
+
+  return 0ul;
+}
+
+static size_t mi_os_numa_node_countx(void) {
+  size_t ndomains = 0;
+  size_t len = sizeof(ndomains);
+
+  if (sysctlbyname("vm.ndomains", &ndomains, &len, NULL, 0) == -1) return 0ul;
+
+  return ndomains;
+}
+#elif defined(__DragonFly__)
+static size_t mi_os_numa_nodex(void) {
+  // TODO DragonFlyBSD does not seem to provide any userland mean to
+  // check this information, even less the possibility to control
+  // the allocation to a logical core level's granularity, only the kernel
+  // is fully NUMA aware at the moment.
+  return 0ul;
+}
+
+static size_t mi_os_numa_node_countx(void) {
+  size_t ncpus = 0, nvirtcoresperphys = 0;
+  size_t len = sizeof(size_t);
+
+  if (sysctlbyname("hw.ncpu", &ncpus, &len, NULL, 0) == -1) return 0ul;
+  if (sysctlbyname("hw.cpu_topology_ht_ids", &nvirtcoresperphys, &len, NULL, 0) == -1) return 0ul;
+
+  return nvirtcoresperphys * ncpus;
+}
 #else
 static size_t mi_os_numa_nodex(void) {
   return 0;
diff --git a/src/page.c b/src/page.c
index 033976dc..7efbcb8d 100644
--- a/src/page.c
+++ b/src/page.c
@@ -84,9 +84,10 @@ static bool mi_page_is_valid_init(mi_page_t* page) {
   mi_assert_internal(mi_page_list_is_valid(page,page->local_free));
 
   #if MI_DEBUG>3 // generally too expensive to check this
-  if (page->flags.is_zero) {
-    for(mi_block_t* block = page->free; block != NULL; mi_block_next(page,block)) {
-      mi_assert_expensive(mi_mem_is_zero(block + 1, page->block_size - sizeof(mi_block_t)));
+  if (page->is_zero) {
+    const size_t ubsize = mi_page_usable_block_size(page);
+    for(mi_block_t* block = page->free; block != NULL; block = mi_block_next(page,block)) {
+      mi_assert_expensive(mi_mem_is_zero(block + 1, ubsize - sizeof(mi_block_t)));
     }
   }
   #endif