X-Git-Url: https://git.kernelconcepts.de/?a=blobdiff_plain;f=mm%2Fvmscan.c;h=8ad39bbc79e67eaff24c42201ae2470ffc21d0a7;hb=667271455f883d23e6418ef3376eb1214da9d066;hp=2f45c0520f43fbcb5696063172cd281553302f9d;hpb=28b47809b2171a6cfbab839936b24280639c9f85;p=karo-tx-linux.git

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2f45c0520f43..8ad39bbc79e6 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1449,7 +1449,7 @@ static __always_inline void update_lru_sizes(struct lruvec *lruvec,
  *
  * Appropriate locks must be held before calling this function.
  *
- * @nr_to_scan:	The number of pages to look through on the list.
+ * @nr_to_scan:	The number of eligible pages to look through on the list.
  * @lruvec:	The LRU vector to pull pages from.
  * @dst:	The temp list to put pages on to.
  * @nr_scanned:	The number of pages that were scanned.
@@ -1469,11 +1469,13 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 	unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };
 	unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };
 	unsigned long skipped = 0;
-	unsigned long scan, nr_pages;
+	unsigned long scan, total_scan, nr_pages;
 	LIST_HEAD(pages_skipped);
 
-	for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan &&
-					!list_empty(src); scan++) {
+	scan = 0;
+	for (total_scan = 0;
+	     scan < nr_to_scan && nr_taken < nr_to_scan && !list_empty(src);
+	     total_scan++) {
 		struct page *page;
 
 		page = lru_to_page(src);
@@ -1487,6 +1489,13 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 			continue;
 		}
 
+		/*
+		 * Do not count skipped pages because that makes the function
+		 * return with no isolated pages if the LRU mostly contains
+		 * ineligible pages.  This causes the VM to not reclaim any
+		 * pages, triggering a premature OOM.
+		 */
+		scan++;
 		switch (__isolate_lru_page(page, mode)) {
 		case 0:
 			nr_pages = hpage_nr_pages(page);
@@ -1524,9 +1533,9 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 			skipped += nr_skipped[zid];
 		}
 	}
-	*nr_scanned = scan;
+	*nr_scanned = total_scan;
 	trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan,
-				    scan, skipped, nr_taken, mode, lru);
+				    total_scan, skipped, nr_taken, mode, lru);
 	update_lru_sizes(lruvec, lru, nr_zone_taken);
 	return nr_taken;
 }