/*
* 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
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); \
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)
/*