diff --git a/share/man/man9/EVENTHANDLER.9 b/share/man/man9/EVENTHANDLER.9
index 3ca835d..bf5d259 100644
--- a/share/man/man9/EVENTHANDLER.9
+++ b/share/man/man9/EVENTHANDLER.9
@@ -213,6 +213,8 @@ Callbacks invoked at shutdown time, before file systems are synchronized.
 Callbacks invoked at shutdown time, after all file systems are synchronized.
 .It Vt shutdown_final
 Callbacks invoked just before halting the system.
+.It Vt vfs_highdirtybuf
+Callbacks invoked when amount of dirty buffers is high.
 .It Vt vm_lowmem
 Callbacks invoked when virtual memory is low.
 .It Vt watchdog_list
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 2a91b2c..18d8497 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -2167,9 +2167,11 @@ SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp);
 static int
 buf_do_flush(struct vnode *vp)
 {
-	int flushed;
+	int flushed = 0;
+
+	EVENTHANDLER_INVOKE(vfs_highdirtybuf, vp, &flushed);
 
-	flushed = flushbufqueues(vp, QUEUE_DIRTY, 0);
+	flushed += flushbufqueues(vp, QUEUE_DIRTY, 0);
 	/* The list empty check here is slightly racy */
 	if (!TAILQ_EMPTY(&bufqueues[QUEUE_DIRTY_GIANT])) {
 		mtx_lock(&Giant);
diff --git a/sys/sys/eventhandler.h b/sys/sys/eventhandler.h
index 6d07cf6..6ab2bc7 100644
--- a/sys/sys/eventhandler.h
+++ b/sys/sys/eventhandler.h
@@ -32,6 +32,7 @@
 #include <sys/lock.h>
 #include <sys/ktr.h>
 #include <sys/mutex.h>
+#include <sys/vnode.h>
 #include <sys/queue.h>
 
 struct eventhandler_entry {
@@ -183,6 +184,10 @@ typedef void (*power_change_fn)(void *);
 EVENTHANDLER_DECLARE(power_resume, power_change_fn);
 EVENTHANDLER_DECLARE(power_suspend, power_change_fn);
 
+/* High dirty buffer event */
+typedef void (*vfs_highdirtybuf_handler_t)(void *, struct vnode *, int *);
+EVENTHANDLER_DECLARE(vfs_highdirtybuf, vfs_highdirtybuf_handler_t);
+
 /* Low memory event */
 typedef void (*vm_lowmem_handler_t)(void *, int);
 #define	LOWMEM_PRI_DEFAULT	EVENTHANDLER_PRI_FIRST