V4L/DVB (4065): Several improvements at videodev.c

[linux-2.6-omap-h63xx.git] / include / linux / page-flags.h

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 9ea629c02a4b98fc7cf06c71b9dd9c74b5a15bde..0c076d58c6760751a3e82fda67c71fc02c7cc83a 100644 (file)
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -7,6 +7,8 @@
 
 #include <linux/percpu.h>
 #include <linux/cache.h>
+#include <linux/types.h>
+
 #include <asm/pgtable.h>
 
 /*
@@ -48,8 +50,20 @@
 
 /*
  * Don't use the *_dontuse flags.  Use the macros.  Otherwise you'll break
- * locked- and dirty-page accounting.  The top eight bits of page->flags are
- * used for page->zone, so putting flag bits there doesn't work.
+ * locked- and dirty-page accounting.
+ *
+ * The page flags field is split into two parts, the main flags area
+ * which extends from the low bits upwards, and the fields area which
+ * extends from the high bits downwards.
+ *
+ *  | FIELD | ... | FLAGS |
+ *  N-1     ^             0
+ *          (N-FLAGS_RESERVED)
+ *
+ * The fields area is reserved for fields mapping zone, node and SPARSEMEM
+ * section.  The boundry between these two areas is defined by
+ * FLAGS_RESERVED which defines the width of the fields section
+ * (see linux/mmzone.h).  New flags must _not_ overlap with this area.
  */
 #define PG_locked               0      /* Page is locked. Don't touch. */
 #define PG_error                1
@@ -74,7 +88,19 @@
 #define PG_mappedtodisk                16      /* Has blocks allocated on-disk */
 #define PG_reclaim             17      /* To be reclaimed asap */
 #define PG_nosave_free         18      /* Free, should not be written */
-#define PG_uncached            19      /* Page has been mapped as uncached */
+#define PG_buddy               19      /* Page is free, on buddy lists */
+
+
+#if (BITS_PER_LONG > 32)
+/*
+ * 64-bit-only flags build down from bit 31
+ *
+ * 32 bit  -------------------------------| FIELDS |       FLAGS         |
+ * 64 bit  |           FIELDS             | ??????         FLAGS         |
+ *         63                            32                              0
+ */
+#define PG_uncached            31      /* Page has been mapped as uncached */
+#endif
 
 /*
  * Global page accounting.  One instance per CPU.  Only unsigned longs are
@@ -317,6 +343,10 @@ extern void __mod_page_state_offset(unsigned long offset, unsigned long delta);
 #define SetPageNosaveFree(page)        set_bit(PG_nosave_free, &(page)->flags)
 #define ClearPageNosaveFree(page)              clear_bit(PG_nosave_free, &(page)->flags)
 
+#define PageBuddy(page)                test_bit(PG_buddy, &(page)->flags)
+#define __SetPageBuddy(page)   __set_bit(PG_buddy, &(page)->flags)
+#define __ClearPageBuddy(page) __clear_bit(PG_buddy, &(page)->flags)
+
 #define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags)
 #define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
 #define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)