diff --git a/src/arena.c b/src/arena.c
index d68a117..fc0390f 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -168,12 +168,13 @@ APool *apool_create_ex(Arena *arena, U32 n_elements, U32 element_size, U32 eleme
     U32 size = AlignUp(element_size, element_align);
 
     APool *pool = arena_push_type(arena, APool);
+    Assert(pool != NULL);
     pool->align = align;
     pool->element_size = size;
     pool->arena = arena;
     pool->n_elements = n_elements;
     pool->free_list = NULL;
-    pool->start == NULL;
+    pool->start = NULL;
 
     if (size != APOOL_AUTOGROW) {
         U32 total_size = n_elements * size; // Note(nos): guard against unreasonable sizes
diff --git a/src/base_core.h b/src/base_core.h
index 8a5f7b7..06be6cc 100644
--- a/src/base_core.h
+++ b/src/base_core.h
@@ -177,7 +177,8 @@ typedef unsigned __int128 U128;
 #define CeilDiv(x, y) (((x) + ((y) - 1)) / (y))
 
 /**
- * Round x up to nearest multiple of y
+ * Round x up to nearest multiple of y:
+ * (((x) + (y) - 1) - (((x) + (y) - 1) % (y)))
  * e.g. RoundUp(30,48) == 48
  * e.g. RoundUp(49,48) == 96
  *
@@ -185,7 +186,15 @@ typedef unsigned __int128 U128;
  * @param y denominator
  * @return x rounded up to nearest multiple of y
  */
-#define RoundUpToMultiple(x, y) (CeilDiv((x), (y)) * (y))
+#define RoundUpToMultiple(x, y)       \
+({                                    \
+    __typeof__(x) _x   = (x);         \
+    __typeof__(y) _y   = (y);         \
+    Assert(_y !        = 0);          \
+    __typeof__(x) _tmp = _x + _y - 1; \
+    _tmp - _tmp % _y;                 \
+})
+
 
 /**
  * Round x down to nearest multiple of y
diff --git a/src/main.c b/src/main.c
index d596b7b..1284859 100644
--- a/src/main.c
+++ b/src/main.c
@@ -194,8 +194,8 @@ void miniarena_test1(void)
 typedef struct PoolTest PoolTest;
 struct PoolTest{
     U32 n;
-    char name[32];
     PoolTest *next;
+    char name[12];
 };
 
 void apool_test(void)
@@ -238,7 +238,7 @@ void apool_test(void)
     for (PoolTest *p = list; p; p = p->next){
         printf("Pooltest %u\n",p->n);
     }
-
+    arena_free(&arena);
 }
 
 void apool_test_autogrow(void)
@@ -291,6 +291,7 @@ int main(int argc, char *argv[])
     // arena_test_3();
     // arena_test_4();
 //    miniarena_test1();
+    apool_test();
     apool_test_autogrow();
 }
 
diff --git a/src/platform.h b/src/platform.h
index dcc28d6..54c3700 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -4,9 +4,9 @@
 void *platform_malloc(size_t size);
 U32 platform_page_size(void);
 
+// Memory functions expect mem and size to be page aligned
 void *memory_allocate_and_commit(size_t size);
 void *memory_reserve(size_t size);
 void memory_commit(void *mem, size_t size);
 void memory_decommit(void *mem, size_t size);
-
 void memory_free(void *mem, size_t size);