3 files changed, 16 insertions, 1 deletions

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 35b00746c712..f1b402a50679 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -285,7 +285,7 @@ enum {
 void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
 void set_bdi_congested(struct backing_dev_info *bdi, int sync);
 long congestion_wait(int sync, long timeout);
-
+long wait_iff_congested(struct zone *zone, int sync, long timeout);
 
 static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
 {
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index c3c17fb675ee..39c24ebe9cfd 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -423,6 +423,9 @@ struct zone {
 typedef enum {
         ZONE_RECLAIM_LOCKED,            /* prevents concurrent reclaim */
         ZONE_OOM_LOCKED,                /* zone is in OOM killer zonelist */
+        ZONE_CONGESTED,                 /* zone has many dirty pages backed by
+                                         * a congested BDI
+                                         */
 } zone_flags_t;
 
 static inline void zone_set_flag(struct zone *zone, zone_flags_t flag)
@@ -440,6 +443,11 @@ static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
         clear_bit(flag, &zone->flags);
 }
 
+static inline int zone_is_reclaim_congested(const struct zone *zone)
+{
+        return test_bit(ZONE_CONGESTED, &zone->flags);
+}
+
 static inline int zone_is_reclaim_locked(const struct zone *zone)
 {
         return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index d2b2654606ec..89a2b2db4375 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -179,6 +179,13 @@ DEFINE_EVENT(writeback_congest_waited_template, writeback_congestion_wait,
         TP_ARGS(usec_timeout, usec_delayed)
 );
 
+DEFINE_EVENT(writeback_congest_waited_template, writeback_wait_iff_congested,
+
+        TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
+
+        TP_ARGS(usec_timeout, usec_delayed)
+);
+
 #endif /* _TRACE_WRITEBACK_H */
 
 /* This part must be outside protection */