Fix: mman behavior

kernel/include/mman.h

@@ -19,7 +19,11 @@ typedef enum :uint8_t {
 
 typedef struct {
   page_state_t state;
-  uint64_t maxsz;
+
+  // when state == PAGE_ALLOCATED or PAGE_RESERVED, size = 0
+  // when state == PAGE_FREE, size = r - l
+  // when state == PAGE_DIVIDED, size = LCH->size | RCH->size
+  uint64_t size;
 } page_header_t;
 
 void mman_init();