per-zone and reclaim enhancements for memory controller: remember reclaim priority in memory cgroup

Functions to remember reclaim priority per cgroup (as zone->prev_priority)

[akpm@linux-foundation.org: build fixes]
[akpm@linux-foundation.org: more build fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/memcontrol.h

@@ -70,6 +70,11 @@ extern void mem_cgroup_page_migration(struct page *page, struct page *newpage);
 extern int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem);
 extern long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem);
 
+extern int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem);
+extern void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem,
+							int priority);
+extern void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,
+							int priority);
 
 
 #else /* CONFIG_CGROUP_MEM_CONT */
@@ -153,6 +158,21 @@ static inline int mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem)
 	return 0;
 }
 
+static inline int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
+{
+	return 0;
+}
+
+static inline void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem,
+						int priority)
+{
+}
+
+static inline void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,
+						int priority)
+{
+}
+
 #endif /* CONFIG_CGROUP_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */

mm/memcontrol.c

@@ -132,6 +132,7 @@ struct mem_cgroup {
 	 */
 	spinlock_t lru_lock;
 	unsigned long control_type;	/* control RSS or RSS+Pagecache */
+	int	prev_priority;	/* for recording reclaim priority */
 	/*
 	 * statistics.
 	 */
@@ -451,6 +452,25 @@ long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem)
 	return (long) (active / (inactive + 1));
 }
 
+/*
+ * prev_priority control...this will be used in memory reclaim path.
+ */
+int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
+{
+	return mem->prev_priority;
+}
+
+void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
+{
+	if (priority < mem->prev_priority)
+		mem->prev_priority = priority;
+}
+
+void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
+{
+	mem->prev_priority = priority;
+}
+
 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
 					struct list_head *dst,
 					unsigned long *scanned, int order,