diff --git a/include/mimalloc/internal.h b/include/mimalloc/internal.h
index fa932cda..e0bcfaea 100644
--- a/include/mimalloc/internal.h
+++ b/include/mimalloc/internal.h
@@ -88,8 +88,10 @@ void       _mi_thread_data_collect(void);
 
 // os.c
 void       _mi_os_init(void);                                            // called from process init
-void*      _mi_os_alloc(size_t size, bool* is_zero, mi_stats_t* stats);  // to allocate thread local data
-void       _mi_os_free(void* p, size_t size, mi_stats_t* stats);         // to free thread local data
+void*      _mi_os_alloc(size_t size, bool* is_zero, mi_stats_t* stats);  
+void       _mi_os_free(void* p, size_t size, mi_stats_t* stats);
+void       _mi_os_free_ex(void* p, size_t size, bool is_committed, mi_stats_t* stats);
+
 size_t     _mi_os_page_size(void);
 size_t     _mi_os_good_alloc_size(size_t size);
 bool       _mi_os_has_overcommit(void);
@@ -106,13 +108,13 @@ bool       _mi_os_purge_ex(void* p, size_t size, bool allow_reset, mi_stats_t* s
 void*      _mi_os_alloc_aligned(size_t size, size_t alignment, bool commit, bool allow_large, bool* is_large, bool* is_zero, mi_stats_t* stats);
 void*      _mi_os_alloc_aligned_at_offset(size_t size, size_t alignment, size_t align_offset, bool commit, bool allow_large, bool* is_large, bool* is_zero, mi_stats_t* tld_stats);
 void       _mi_os_free_aligned_at_offset(void* p, size_t size, size_t alignment, size_t align_offset, bool was_committed, mi_stats_t* tld_stats);
+
 void*      _mi_os_get_aligned_hint(size_t try_alignment, size_t size);
 bool       _mi_os_use_large_page(size_t size, size_t alignment);
 size_t     _mi_os_large_page_size(void);
 
-void       _mi_os_free_ex(void* p, size_t size, bool was_committed, mi_stats_t* stats);
 void*      _mi_os_alloc_huge_os_pages(size_t pages, int numa_node, mi_msecs_t max_secs, size_t* pages_reserved, size_t* psize, bool* is_zero);
-void       _mi_os_free_huge_pages(void* p, size_t size, mi_stats_t* stats);
+void       _mi_os_free_huge_os_pages(void* p, size_t size, mi_stats_t* stats);
 
 // arena.c
 mi_arena_id_t _mi_arena_id_none(void);
@@ -838,6 +840,8 @@ static inline void _mi_memzero(void* dst, size_t n) {
 }
 #endif
 
+// initialize a local variable to zero; use memset as compilers optimize constant sized memset's
+#define _mi_memzero_var(x)  memset(&x,0,sizeof(x))
 
 // -------------------------------------------------------------------------------
 // The `_mi_memcpy_aligned` can be used if the pointers are machine-word aligned
diff --git a/src/arena.c b/src/arena.c
index 473bdc55..f9b844bc 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -96,22 +96,19 @@ static bool mi_arena_id_is_suitable(mi_arena_id_t arena_id, bool arena_is_exclus
   memory id's
 ----------------------------------------------------------- */
 
-static mi_memid_t mi_memid_none(void) {
-  mi_memid_t memid;
-  _mi_memzero(&memid, sizeof(memid));
-  memid.memkind = MI_MEM_NONE;
-  return memid;
-}
-
 static mi_memid_t mi_memid_create(mi_memkind_t memkind) {
-  mi_memid_t memid = mi_memid_none();
+  mi_memid_t memid;
+  _mi_memzero_var(memid);
   memid.memkind = memkind;
   return memid;
 }
 
+static mi_memid_t mi_memid_none(void) {
+  return mi_memid_create(MI_MEM_NONE);
+}
+
 static mi_memid_t mi_memid_create_os(bool committed) {
-  mi_memid_t memid = mi_memid_none();
-  memid.memkind = MI_MEM_OS;
+  mi_memid_t memid = mi_memid_create(MI_MEM_OS);
   memid.was_committed = committed;
   return memid;
 }
@@ -163,11 +160,10 @@ static bool mi_arena_memid_indices(mi_memid_t memid, size_t* arena_index, mi_bit
 
 /* -----------------------------------------------------------
   Special static area for mimalloc internal structures
-  to avoid OS calls (for example, for the arena and thread
-  metadata)
+  to avoid OS calls (for example, for the arena metadata)
 ----------------------------------------------------------- */
 
-#define MI_ARENA_STATIC_MAX  (MI_INTPTR_SIZE*8*MI_KiB)  // 64 KiB on 64-bit
+#define MI_ARENA_STATIC_MAX  (MI_INTPTR_SIZE*MI_KiB)  // 8 KiB on 64-bit
 
 static uint8_t mi_arena_static[MI_ARENA_STATIC_MAX];
 static _Atomic(size_t) mi_arena_static_top;
@@ -209,7 +205,7 @@ static void* mi_arena_meta_zalloc(size_t size, mi_memid_t* memid, mi_stats_t* st
   p = _mi_os_alloc(size, &is_zero, stats);
   if (p != NULL) {
     *memid = mi_memid_create_os(true);
-    if (!is_zero) { _mi_memzero(p, size); }
+    if (!is_zero) { _mi_memzero_aligned(p, size); }
     return p;
   }
 
@@ -724,7 +720,7 @@ static void mi_arenas_unsafe_destroy(void) {
       if (arena->owned && arena->start != NULL) {
         mi_atomic_store_ptr_release(mi_arena_t, &mi_arenas[i], NULL);
         if (arena->is_huge_alloc) { 
-          _mi_os_free_huge_pages(arena->start, mi_arena_size(arena), &_mi_stats_main); 
+          _mi_os_free_huge_os_pages(arena->start, mi_arena_size(arena), &_mi_stats_main); 
         }
         else {
           _mi_os_free(arena->start, mi_arena_size(arena), &_mi_stats_main); 
@@ -938,7 +934,7 @@ int mi_reserve_huge_os_pages_at_ex(size_t pages, int numa_node, size_t timeout_m
   _mi_verbose_message("numa node %i: reserved %zu GiB huge pages (of the %zu GiB requested)\n", numa_node, pages_reserved, pages);
 
   if (!mi_manage_os_memory_ex2(p, hsize, true, true, true, is_zero, numa_node, exclusive, true /* owned */, arena_id)) {
-    _mi_os_free_huge_pages(p, hsize, &_mi_stats_main);
+    _mi_os_free_huge_os_pages(p, hsize, &_mi_stats_main);
     return ENOMEM;
   }
   return 0;
diff --git a/src/init.c b/src/init.c
index 8ab0f943..6dc61c48 100644
--- a/src/init.c
+++ b/src/init.c
@@ -217,7 +217,7 @@ static mi_thread_data_t* mi_thread_data_zalloc(void) {
   }
   
   if (td != NULL && !is_zero) {
-    _mi_memzero(td, sizeof(*td));
+    _mi_memzero_aligned(td, sizeof(*td));
   }
   return td;
 }
diff --git a/src/os.c b/src/os.c
index cffeed29..cf53472f 100644
--- a/src/os.c
+++ b/src/os.c
@@ -599,7 +599,7 @@ void* _mi_os_alloc_huge_os_pages(size_t pages, int numa_node, mi_msecs_t max_mse
 
 // free every huge page in a range individually (as we allocated per page)
 // note: needed with VirtualAlloc but could potentially be done in one go on mmap'd systems.
-void _mi_os_free_huge_pages(void* p, size_t size, mi_stats_t* stats) {
+void _mi_os_free_huge_os_pages(void* p, size_t size, mi_stats_t* stats) {
   if (p==NULL || size==0) return;
   uint8_t* base = (uint8_t*)p;
   while (size >= MI_HUGE_OS_PAGE_SIZE) {
diff --git a/src/stats.c b/src/stats.c
index 448248c7..a8eac648 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -444,7 +444,7 @@ mi_msecs_t _mi_clock_end(mi_msecs_t start) {
 mi_decl_export void mi_process_info(size_t* elapsed_msecs, size_t* user_msecs, size_t* system_msecs, size_t* current_rss, size_t* peak_rss, size_t* current_commit, size_t* peak_commit, size_t* page_faults) mi_attr_noexcept
 {
   mi_process_info_t pinfo;
-  _mi_memzero(&pinfo,sizeof(pinfo));
+  _mi_memzero_var(pinfo);
   pinfo.elapsed        = _mi_clock_end(mi_process_start);
   pinfo.current_commit = (size_t)(mi_atomic_loadi64_relaxed((_Atomic(int64_t)*)&_mi_stats_main.committed.current));
   pinfo.peak_commit    = (size_t)(mi_atomic_loadi64_relaxed((_Atomic(int64_t)*)&_mi_stats_main.committed.peak));