vmscan: tracing: add trace events for LRU page isolation

Add an event for when pages are isolated en-masse from the LRU lists.
This event augments the information available on LRU traffic and can be
used to evaluate lumpy reclaim.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Larry Woodman <lwoodman@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michael Rubin <mrubin@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c99bc418c4cf..3d006d91a526 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -919,6 +919,9 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
                 unsigned long *scanned, int order, int mode, int file)
 {
         unsigned long nr_taken = 0;
+        unsigned long nr_lumpy_taken = 0;
+        unsigned long nr_lumpy_dirty = 0;
+        unsigned long nr_lumpy_failed = 0;
         unsigned long scan;
 
         for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) {
@@ -996,12 +999,25 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
                                 list_move(&cursor_page->lru, dst);
                                 mem_cgroup_del_lru(cursor_page);
                                 nr_taken++;
+                                nr_lumpy_taken++;
+                                if (PageDirty(cursor_page))
+                                        nr_lumpy_dirty++;
                                 scan++;
+                        } else {
+                                if (mode == ISOLATE_BOTH &&
+                                                page_count(cursor_page))
+                                        nr_lumpy_failed++;
                         }
                 }
         }
 
         *scanned = scan;
+
+        trace_mm_vmscan_lru_isolate(order,
+                        nr_to_scan, scan,
+                        nr_taken,
+                        nr_lumpy_taken, nr_lumpy_dirty, nr_lumpy_failed,
+                        mode);
         return nr_taken;
 }