[PATCH] mm: vmscan: decrease cma pages from nr_reclaimed

[Haojian Zhuang <haojian.zhuang@gmail.com>]

shrink_page_list() reclaims the pages. But the statistical data may
be inaccurate since some pages are CMA pages. If kernel needs to
reclaim unmovable memory (GFP_KERNEL flag), free CMA pages should not
be counted in nr_reclaimed pages.

Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>
---
 mm/vmscan.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2cff0d4..0cbe393 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -720,6 +720,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 	unsigned long nr_reclaimed = 0;
 	unsigned long nr_writeback = 0;
 	unsigned long nr_immediate = 0;
+#ifdef CONFIG_CMA
+	/* Number of pages freed with MIGRATE_CMA type */
+	unsigned long nr_reclaimed_cma = 0;
+#endif
 
 	cond_resched();
 
@@ -987,6 +991,11 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 					 * leave it off the LRU).
 					 */
 					nr_reclaimed++;
+#ifdef CONFIG_CMA
+					if (get_pageblock_migratetype(page) ==
+						MIGRATE_CMA)
+						nr_reclaimed_cma++;
+#endif
 					continue;
 				}
 			}
@@ -1005,6 +1014,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 		__clear_page_locked(page);
 free_it:
 		nr_reclaimed++;
+#ifdef CONFIG_CMA
+		if (get_pageblock_migratetype(page) == MIGRATE_CMA)
+			nr_reclaimed_cma++;
+#endif
 
 		/*
 		 * Is there need to periodically free_page_list? It would
@@ -1044,6 +1057,10 @@ keep:
 	*ret_nr_unqueued_dirty += nr_unqueued_dirty;
 	*ret_nr_writeback += nr_writeback;
 	*ret_nr_immediate += nr_immediate;
+#ifdef CONFIG_CMA
+	if (allocflags_to_migratetype(sc->gfp_mask) == MIGRATE_UNMOVABLE)
+		nr_reclaimed -= nr_reclaimed_cma;
+#endif
 	return nr_reclaimed;
 }
 
-- 
1.8.1.2

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