1 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 2cd4359cb38c..ad8f1a397ae4 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -184,6 +184,23 @@ struct memcg_padding {
 #endif
 
 /*
+ * Remember four most recent foreign writebacks with dirty pages in this
+ * cgroup.  Inode sharing is expected to be uncommon and, even if we miss
+ * one in a given round, we're likely to catch it later if it keeps
+ * foreign-dirtying, so a fairly low count should be enough.
+ *
+ * See mem_cgroup_track_foreign_dirty_slowpath() for details.
+ */
+#define MEMCG_CGWB_FRN_CNT	4
+
+struct memcg_cgwb_frn {
+	u64 bdi_id;			/* bdi->id of the foreign inode */
+	int memcg_id;			/* memcg->css.id of foreign inode */
+	u64 at;				/* jiffies_64 at the time of dirtying */
+	struct wb_completion done;	/* tracks in-flight foreign writebacks */
+};
+
+/*
  * The memory controller data structure. The memory controller controls both
  * page cache and RSS per cgroup. We would eventually like to provide
  * statistics based on the statistics developed by Rik Van Riel for clock-pro,
@@ -307,6 +324,7 @@ struct mem_cgroup {
 #ifdef CONFIG_CGROUP_WRITEBACK
 	struct list_head cgwb_list;
 	struct wb_domain cgwb_domain;
+	struct memcg_cgwb_frn cgwb_frn[MEMCG_CGWB_FRN_CNT];
 #endif
 
 	/* List of events which userspace want to receive */
@@ -1237,6 +1255,18 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
 			 unsigned long *pheadroom, unsigned long *pdirty,
 			 unsigned long *pwriteback);
 
+void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
+					     struct bdi_writeback *wb);
+
+static inline void mem_cgroup_track_foreign_dirty(struct page *page,
+						  struct bdi_writeback *wb)
+{
+	if (unlikely(&page->mem_cgroup->css != wb->memcg_css))
+		mem_cgroup_track_foreign_dirty_slowpath(page, wb);
+}
+
+void mem_cgroup_flush_foreign(struct bdi_writeback *wb);
+
 #else	/* CONFIG_CGROUP_WRITEBACK */
 
 static inline struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
@@ -1252,6 +1282,15 @@ static inline void mem_cgroup_wb_stats(struct bdi_writeback *wb,
 {
 }
 
+static inline void mem_cgroup_track_foreign_dirty(struct page *page,
+						  struct bdi_writeback *wb)
+{
+}
+
+static inline void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
+{
+}
+
 #endif	/* CONFIG_CGROUP_WRITEBACK */
 
 struct sock;