diff --git a/src/mem.cpp b/src/mem.cpp
index c1012b0..5ca3052 100644
--- a/src/mem.cpp
+++ b/src/mem.cpp
@@ -39,6 +39,7 @@ Arena *arena_alloc_sized(u64 init_res, u64 init_cmt)
     arena->res = res;
     arena->align = 8;
     arena->grow = true;
+    arena->mem_used = arena->mem_peak_used = ARENA_HEADER_SIZE;
   }
 
   return arena;
@@ -59,16 +60,6 @@ void arena_release(Arena *arena)
   }
 }
 
-internal u64
-arena_mem_used(Arena *arena)
-{
-  u64 tot = 0;
-  for (Arena *node = arena->cur, *prev = 0; node; node = prev) {
-    tot += node->pos - node->base_pos;
-  }
-  return tot;
-}
-
 internal
 u64 arena_huge_push_threshold()
 {
@@ -117,8 +108,11 @@ void *arena_push_impl(Arena *arena, u64 size)
   void *mem = 0;
   if (cur->cmt >= pos_new) {
     mem = (u8*)cur + pos_mem;
+    u64 added_size = pos_new - cur->pos;
+    arena->mem_used += added_size;
+    arena->mem_peak_used = max(arena->mem_peak_used, arena->mem_used);
     cur->pos = pos_new;
-    asan_unpoison_memory_region(mem, size);
+    asan_unpoison_memory_region(mem, added_size);
   }
 
   return mem;
@@ -158,15 +152,15 @@ T *arena_push_array(Arena *arena, u64 count)
   return ary;
 }
 
-// internal
-// u8 *arena_push_contiguous(Arena *arena, u64 size)
-// {
-//   b32 restore = arena->grow;
-//   arena->grow = 0;
-//   void *mem = arena_push_impl(arena, size);
-//   arena->grow = restore;
-//   return (u8 *)mem;
-// }
+internal
+u8 *arena_push_contiguous(Arena *arena, u64 size)
+{
+  b32 restore = arena->grow;
+  arena->grow = 0;
+  void *mem = arena_push_impl(arena, size);
+  arena->grow = restore;
+  return (u8 *)mem;
+}
 
 internal
 u64 arena_pos(Arena *arena)
@@ -196,6 +190,8 @@ void arena_pop_to(Arena *arena, u64 big_pos_unclamped)
   
   // poison popped memory block
   asan_poison_memory_region((u8*)current + new_pos, (current->pos - new_pos));
+
+  arena->mem_used -= (current->pos - new_pos);
   
   // update position
   current->pos = new_pos;
diff --git a/src/mem.h b/src/mem.h
index 9b9f172..1bad0c6 100644
--- a/src/mem.h
+++ b/src/mem.h
@@ -10,6 +10,8 @@ struct Arena {
   u64 cmt;
   u64 res;
   u64 align;
+  u64 mem_used;
+  u64 mem_peak_used;
   b8 grow;
 };