1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 04a3786c456f..3b73e97ecfc7 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -132,6 +132,26 @@ struct wb_domain {
 	unsigned long dirty_limit;
 };
 
+/**
+ * wb_domain_size_changed - memory available to a wb_domain has changed
+ * @dom: wb_domain of interest
+ *
+ * This function should be called when the amount of memory available to
+ * @dom has changed.  It resets @dom's dirty limit parameters to prevent
+ * the past values which don't match the current configuration from skewing
+ * dirty throttling.  Without this, when memory size of a wb_domain is
+ * greatly reduced, the dirty throttling logic may allow too many pages to
+ * be dirtied leading to consecutive unnecessary OOMs and may get stuck in
+ * that situation.
+ */
+static inline void wb_domain_size_changed(struct wb_domain *dom)
+{
+	spin_lock(&dom->lock);
+	dom->dirty_limit_tstamp = jiffies;
+	dom->dirty_limit = 0;
+	spin_unlock(&dom->lock);
+}
+
 /*
  * fs/fs-writeback.c
  */