Index: cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
===================================================================
--- cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c	(revision 305005)
+++ cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c	(working copy)
@@ -237,7 +237,16 @@ int zfs_arc_p_min_shift = 0;
 int zfs_disable_dup_eviction = 0;
 uint64_t zfs_arc_average_blocksize = 8 * 1024; /* 8KB */
 u_int zfs_arc_free_target = 0;
+u_int zfs_arc_wakeup_pager = 0;
+u_int zfs_arc_wakeup_delay = 500;
 
+#define	WAKE_PAGER
+#ifdef	WAKE_PAGER
+#define	WAKE_PAGER_CONSTANT	10 / 9	/* Pager wakeup threshold */
+static	int	arc_init_done = 0;	/* After arc_warm is valid */
+extern void pagedaemon_wakeup(void);
+#endif
+
 /* Absolute min for arc min / max is 16MB. */
 static uint64_t arc_abs_min = 16 << 20;
 
@@ -252,6 +261,7 @@ arc_free_target_init(void *unused __unused)
 {
 
 	zfs_arc_free_target = vm_pageout_wakeup_thresh;
+	zfs_arc_wakeup_pager = zfs_arc_free_target * WAKE_PAGER_CONSTANT;
 }
 SYSINIT(arc_free_target_init, SI_SUB_KTHREAD_PAGE, SI_ORDER_ANY,
     arc_free_target_init, NULL);
@@ -3476,6 +3486,11 @@ int64_t arc_pages_pp_reserve = 64;
 int64_t arc_swapfs_reserve = 64;
 
 /*
+ * Declare file-local static for event processor bypass
+ */
+static unsigned int arc_no_wake_event = 0;
+
+/*
  * Return the amount of memory that can be consumed before reclaim will be
  * needed.  Positive if there is sufficient free memory, negative indicates
  * the amount of memory that needs to be freed up.
@@ -3488,6 +3503,12 @@ arc_available_memory(void)
 	free_memory_reason_t r = FMR_UNKNOWN;
 
 #ifdef _KERNEL
+#ifdef WAKE_PAGER
+	sbintime_t now;
+	static sbintime_t last_pagedaemon_wake = 0;
+	void call_arc_kmem_reap(void);
+#endif	/* WAKE_PAGER */
+
 	if (needfree > 0) {
 		n = PAGESIZE * (-needfree);
 		if (n < lowest) {
@@ -3495,6 +3516,25 @@ arc_available_memory(void)
 			r = FMR_NEEDFREE;
 		}
 	}
+#ifdef WAKE_PAGER
+/*
+ * If memory is less than the ARC wakeup threshold and time has expired since
+ * the last time we woke the pager... Do not execute until the ARC warms up.
+ */
+	if ((arc_init_done) &&
+		(((int64_t) freemem - zfs_arc_wakeup_pager) < 0) &&
+		(arc_warm == B_TRUE)
+	) {
+		now = getsbinuptime();
+		if ((now - last_pagedaemon_wake) / SBT_1MS > zfs_arc_wakeup_delay) {
+			last_pagedaemon_wake = now;
+			arc_no_wake_event++;    /* Set bypass flag for ARC */
+			call_arc_kmem_reap();	/* Reap caches if we're close */
+			DTRACE_PROBE(arc__wake_pagedaemon);
+			(void) pagedaemon_wakeup();    /* Wake the pager */
+		}
+	}
+#endif /* WAKE_PAGER */
 
 	/*
 	 * Cooperate with pagedaemon when it's time for it to scan
@@ -3684,6 +3724,11 @@ arc_kmem_reap_now(void)
 	DTRACE_PROBE(arc__kmem_reap_end);
 }
 
+void	call_arc_kmem_reap()
+{
+	arc_kmem_reap_now();
+}
+
 /*
  * Threads can block in arc_get_data_buf() waiting for this thread to evict
  * enough data and signal them to proceed. When this happens, the threads in
@@ -5431,6 +5476,10 @@ static eventhandler_tag arc_event_lowmem = NULL;
 static void
 arc_lowmem(void *arg __unused, int howto __unused)
 {
+	if (arc_no_wake_event) {        /* Don't do it if we woke the pager */
+		arc_no_wake_event = 0;  /* Just clear the flag */
+		return;
+	}
 
 	mutex_enter(&arc_reclaim_lock);
 	/* XXX: Memory deficit should be passed as argument. */
@@ -5696,6 +5745,9 @@ arc_init(void)
 		printf("             in /boot/loader.conf.\n");
 	}
 #endif
+#ifdef	WAKE_PAGER
+	arc_init_done++;
+#endif	/* WAKE_PAGER */
 }
 
 void