gistfile1.txt

diff -uNr kernel-3.10.0-123.el7/linux-3.10.0-123.el7.x86_64/include/trace/events/vmscan.h kernel-3.10.0-123.el7p/linux-3.10.0-123.el7.x86_64/include/trace/events/vmscan.h
--- a/include/trace/events/vmscan.h	2014-05-05 14:58:32.000000000 +0000
+++ b/include/trace/events/vmscan.h	2014-11-12 00:07:59.193842097 +0000
@@ -36,6 +36,25 @@
 		(RECLAIM_WB_ASYNC) \
 	)
 
+TRACE_EVENT(mm_vmscan_frob,
+
+	TP_PROTO(unsigned long  zonefile, unsigned long zonefree),
+
+	TP_ARGS(zonefile, zonefree),
+
+	TP_STRUCT__entry(
+		__field(	unsigned long,	zonefile	)
+		__field(	unsigned long,	zonefree	)
+	),
+
+	TP_fast_assign(
+		__entry->zonefile	= zonefile;
+		__entry->zonefree	= zonefree;
+	),
+
+	TP_printk("file=%lu free =%lu", __entry->zonefile, __entry->zonefree)
+);
+
 TRACE_EVENT(mm_vmscan_kswapd_sleep,
 
 	TP_PROTO(int nid),
diff -uNr kernel-3.10.0-123.el7/linux-3.10.0-123.el7.x86_64/mm/vmscan.c kernel-3.10.0-123.el7p/linux-3.10.0-123.el7.x86_64/mm/vmscan.c
--- a/mm/vmscan.c	2014-05-05 14:58:32.000000000 +0000
+++ b/mm/vmscan.c	2014-11-12 00:08:00.754875382 +0000
@@ -1857,6 +1857,30 @@
 		goto out;
 	}
 
+	/*
+	 * Prevent the reclaimer from falling into the cache trap: as
+	 * cache pages start out inactive, every cache fault will tip
+	 * the scan balance towards the file LRU.  And as the file LRU
+	 * shrinks, so does the window for rotation from references.
+	 * This means we have a runaway feedback loop where a tiny
+	 * thrashing file LRU becomes infinitely more attractive than
+	 * anon pages.  Try to detect this based on file LRU size.
+	 */
+	if (global_reclaim(sc)) {
+		unsigned long zonefile;
+		unsigned long zonefree;
+
+		zonefree = zone_page_state(zone, NR_FREE_PAGES);
+		zonefile = zone_page_state(zone, NR_ACTIVE_FILE) +
+			   zone_page_state(zone, NR_INACTIVE_FILE);
+
+		if (unlikely(zonefile + zonefree <= high_wmark_pages(zone))) {
+			trace_mm_vmscan_frob(zonefree, zonefile);
+			scan_balance = SCAN_ANON;
+			goto out;
+		}
+	}
+
 	anon  = get_lru_size(lruvec, LRU_ACTIVE_ANON) +
 		get_lru_size(lruvec, LRU_INACTIVE_ANON);
 	file  = get_lru_size(lruvec, LRU_ACTIVE_FILE) +