0.9.18.29: --dynamic-space-size command-line switch

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

diff --git a/src/runtime/gencgc-internal.h b/src/runtime/gencgc-internal.h
index 41642ec..c9fe3b5 100644 (file)
--- a/src/runtime/gencgc-internal.h
+++ b/src/runtime/gencgc-internal.h
@@ -19,23 +19,39 @@
 #ifndef _GENCGC_INTERNAL_H_
 #define _GENCGC_INTERNAL_H_
 
+#include <limits.h>
 #include "gc.h"
 #include "gencgc-alloc-region.h"
 #include "genesis/code.h"
 
-/* Size of a page, in bytes. FIXME: needs to be conditionalized per
- * architecture, preferably by someone with a clue as to what page
- * sizes are on archs other than x86 and PPC - Patrik */
-#define PAGE_BYTES 4096
-
 void gc_free_heap(void);
 inline page_index_t find_page_index(void *);
 inline void *page_address(page_index_t);
 int gencgc_handle_wp_violation(void *);
 \f
 struct page {
+    /* The name of this field is not well-chosen for its actual use.
+     * This is the offset from the start of the page to the start
+     * of the alloc_region which contains/contained it.  It's negative or 0
+     */
+    long  first_object_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
+     * allocation regions. It should be 0 for all unallocated pages (not
+     * hard to achieve).
+     *
+     * Currently declared as an unsigned short to make the struct size
+     * smaller. This means that GENCGC-PAGE-SIZE is constrained to fit
+     * inside a short.
+     */
+    unsigned short bytes_used;
+
+#if USHRT_MAX < PAGE_BYTES
+#error "PAGE_BYTES too large"
+#endif
 
-    unsigned int
+    unsigned
         /* 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
@@ -57,34 +73,23 @@ struct page {
         /* If the page is part of a large object then this flag is
          * set. No other objects should be allocated to these pages.
          * This is only valid when the page is allocated. */
-        large_object :1;
+        large_object :1,
+        /* True if the page is known to contain only zeroes. */
+        need_to_zero :1;
 
     /* the generation that this page belongs to. This should be valid
      * for all pages that may have objects allocated, even current
      * allocation region pages - this allows the space of an object to
      * be easily determined. */
     generation_index_t gen;
-
-    /* the number of bytes of this page that are used. This may be less
-     * than the actual bytes used for pages within the current
-     * allocation regions. It should be 0 for all unallocated pages (not
-     * hard to achieve). */
-    int  bytes_used;
-
-    /* The name of this field is not well-chosen for its actual use.
-     * This is the offset from the start of the page to the start
-     * of the alloc_region which contains/contained it.  It's negative or 0
-     */
-    long  first_object_offset;
 };
 
+
 /* values for the page.allocated field */
 
 \f
-/* the number of pages needed for the dynamic space - rounding up */
-#define NUM_PAGES ((page_index_t) ((DYNAMIC_SPACE_SIZE+PAGE_BYTES-1)/PAGE_BYTES))
-
-extern struct page page_table[NUM_PAGES];
+extern unsigned page_table_pages;
+extern struct page *page_table;
 
 \f
 /* forward declarations */
@@ -107,7 +112,7 @@ space_matches_p(lispobj obj, generation_index_t space)
     page_index_t page_index=(void*)obj - (void *)DYNAMIC_SPACE_START;
     return ((page_index >= 0)
             && ((page_index =
-                 ((unsigned long)page_index)/PAGE_BYTES) < NUM_PAGES)
+                 ((unsigned long)page_index)/PAGE_BYTES) < page_table_pages)
             && (page_table[page_index].gen == space));
 }