Simplify (and robustify) regular PACKing

[sbcl.git] / src / runtime / gencgc-internal.h

diff --git a/src/runtime/gencgc-internal.h b/src/runtime/gencgc-internal.h
index bbffe83..574b198 100644 (file)
--- a/src/runtime/gencgc-internal.h
+++ b/src/runtime/gencgc-internal.h
@@ -51,10 +51,14 @@ int gencgc_handle_wp_violation(void *);
  * output the C version in genesis. -- JES, 2006-12-30.
  */
 struct page {
-    /* This is the offset from the start of the page to the start of
-     * the alloc_region which contains/contained it.
+    /* This is the offset from the first byte of some object in memory
+     * prior to and no closer than the start of the page to the start
+     * of the page.  Lower values here are better, 0 is ideal.  This
+     * is useful for determining where to start when scanning forward
+     * through a heap page (either for conservative root validation or
+     * for scavenging).
      */
-    os_vm_size_t region_start_offset;
+    os_vm_size_t scan_start_offset;
 
     /* the number of bytes of this page that are used. This may be less
      * than the actual bytes used for pages within the current
@@ -63,7 +67,7 @@ struct page {
      */
     page_bytes_t bytes_used;
 
-    unsigned
+    unsigned char
         /* This is set when the page is write-protected. This should
          * always reflect the actual write_protect status of a page.
          * (If the page is written into, we catch the exception, make
@@ -112,9 +116,10 @@ extern struct page *page_table;
 
 \f
 /* forward declarations */
-
+#ifdef LISP_FEATURE_X86
 void sniff_code_object(struct code *code, os_vm_size_t displacement);
 void gencgc_apply_code_fixups(struct code *old_code, struct code *new_code);
+#endif
 
 sword_t update_dynamic_space_free_pointer(void);
 void gc_alloc_update_page_tables(int page_type_flag, struct alloc_region *alloc_region);