Merge branch 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block

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

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 32d09c8..d52999c 100644 (file)
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -79,13 +79,23 @@
 /*
  * Global page accounting.  One instance per CPU.  Only unsigned longs are
  * allowed.
+ *
+ * - Fields can be modified with xxx_page_state and xxx_page_state_zone at
+ * any time safely (which protects the instance from modification by
+ * interrupt.
+ * - The __xxx_page_state variants can be used safely when interrupts are
+ * disabled.
+ * - The __xxx_page_state variants can be used if the field is only
+ * modified from process context, or only modified from interrupt context.
+ * In this case, the field should be commented here.
  */
 struct page_state {
        unsigned long nr_dirty;         /* Dirty writeable pages */
        unsigned long nr_writeback;     /* Pages under writeback */
        unsigned long nr_unstable;      /* NFS unstable pages */
        unsigned long nr_page_table_pages;/* Pages used for pagetables */
-       unsigned long nr_mapped;        /* mapped into pagetables */
+       unsigned long nr_mapped;        /* mapped into pagetables.
+                                        * only modified from process context */
        unsigned long nr_slab;          /* In slab */
 #define GET_PAGE_STATE_LAST nr_slab
 
@@ -144,22 +154,33 @@ struct page_state {
 extern void get_page_state(struct page_state *ret);
 extern void get_page_state_node(struct page_state *ret, int node);
 extern void get_full_page_state(struct page_state *ret);
-extern unsigned long __read_page_state(unsigned long offset);
-extern void __mod_page_state(unsigned long offset, unsigned long delta);
+extern unsigned long read_page_state_offset(unsigned long offset);
+extern void mod_page_state_offset(unsigned long offset, unsigned long delta);
+extern void __mod_page_state_offset(unsigned long offset, unsigned long delta);
 
 #define read_page_state(member) \
-       __read_page_state(offsetof(struct page_state, member))
+       read_page_state_offset(offsetof(struct page_state, member))
 
 #define mod_page_state(member, delta)  \
-       __mod_page_state(offsetof(struct page_state, member), (delta))
+       mod_page_state_offset(offsetof(struct page_state, member), (delta))
 
-#define inc_page_state(member) mod_page_state(member, 1UL)
-#define dec_page_state(member) mod_page_state(member, 0UL - 1)
-#define add_page_state(member,delta) mod_page_state(member, (delta))
-#define sub_page_state(member,delta) mod_page_state(member, 0UL - (delta))
+#define __mod_page_state(member, delta)        \
+       __mod_page_state_offset(offsetof(struct page_state, member), (delta))
 
-#define mod_page_state_zone(zone, member, delta)                       \
- do {                                                                  \
+#define inc_page_state(member)         mod_page_state(member, 1UL)
+#define dec_page_state(member)         mod_page_state(member, 0UL - 1)
+#define add_page_state(member,delta)   mod_page_state(member, (delta))
+#define sub_page_state(member,delta)   mod_page_state(member, 0UL - (delta))
+
+#define __inc_page_state(member)       __mod_page_state(member, 1UL)
+#define __dec_page_state(member)       __mod_page_state(member, 0UL - 1)
+#define __add_page_state(member,delta) __mod_page_state(member, (delta))
+#define __sub_page_state(member,delta) __mod_page_state(member, 0UL - (delta))
+
+#define page_state(member) (*__page_state(offsetof(struct page_state, member)))
+
+#define state_zone_offset(zone, member)                                        \
+({                                                                     \
        unsigned offset;                                                \
        if (is_highmem(zone))                                           \
                offset = offsetof(struct page_state, member##_high);    \
@@ -169,7 +190,17 @@ extern void __mod_page_state(unsigned long offset, unsigned long delta);
                offset = offsetof(struct page_state, member##_dma32);   \
        else                                                            \
                offset = offsetof(struct page_state, member##_dma);     \
-       __mod_page_state(offset, (delta));                              \
+       offset;                                                         \
+})
+
+#define __mod_page_state_zone(zone, member, delta)                     \
+ do {                                                                  \
+       __mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
+ } while (0)
+
+#define mod_page_state_zone(zone, member, delta)                       \
+ do {                                                                  \
+       mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
  } while (0)
 
 /*