[PATCH 2/2] mm: compaction: add /proc/vmstat entry for rescued MIGRATE_UNMOVABLE pageblocks

[Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>]

From: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Subject: [PATCH] mm: compaction: add /proc/vmstat entry for rescued MIGRATE_UNMOVABLE pageblocks

compact_rescued_unmovable_blocks shows the number of MIGRATE_UNMOVABLE
pageblocks converted back to MIGRATE_MOVABLE type by the memory compaction
code.  Non-zero values indicate that large kernel-originated allocations
of MIGRATE_UNMOVABLE type happen in the system and need special handling 
from the memory compaction code.

This new vmstat entry is optional but useful for development and understanding
the system.

Cc: Hugh Dickins <hughd@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---

 include/linux/vm_event_item.h |    1 +
 mm/compaction.c               |    2 ++
 mm/vmstat.c                   |    1 +
 3 files changed, 4 insertions(+)

Index: b/include/linux/vm_event_item.h
===================================================================
--- a/include/linux/vm_event_item.h	2012-06-14 11:28:48.812775316 +0200
+++ b/include/linux/vm_event_item.h	2012-06-14 11:31:17.132775300 +0200
@@ -39,6 +39,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS
 #ifdef CONFIG_COMPACTION
 		COMPACTBLOCKS, COMPACTPAGES, COMPACTPAGEFAILED,
 		COMPACTSTALL, COMPACTFAIL, COMPACTSUCCESS,
+		COMPACT_RESCUED_UNMOVABLE_BLOCKS,
 #endif
 #ifdef CONFIG_HUGETLB_PAGE
 		HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
Index: b/mm/compaction.c
===================================================================
--- a/mm/compaction.c	2012-06-14 11:31:24.800775299 +0200
+++ b/mm/compaction.c	2012-06-14 11:31:31.612775298 +0200
@@ -387,6 +387,8 @@ static void rescue_unmovable_pageblock(s
 {
 	set_pageblock_migratetype(page, MIGRATE_MOVABLE);
 	move_freepages_block(page_zone(page), page, MIGRATE_MOVABLE);
+
+	count_vm_event(COMPACT_RESCUED_UNMOVABLE_BLOCKS);
 }
 
 /*
Index: b/mm/vmstat.c
===================================================================
--- a/mm/vmstat.c	2012-06-14 11:28:48.824775319 +0200
+++ b/mm/vmstat.c	2012-06-14 11:31:17.132775300 +0200
@@ -767,6 +767,7 @@ const char * const vmstat_text[] = {
 	"compact_stall",
 	"compact_fail",
 	"compact_success",
+	"compact_rescued_unmovable_blocks",
 #endif
 
 #ifdef CONFIG_HUGETLB_PAGE

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