[RFC v2 PATCH 2/8] mm: introduce MIGRATE_MIRROR to manage the mirrored pages

[Xishi Qiu]

This patch introduces a new migratetype called "MIGRATE_MIRROR", it is used to
allocate mirrored pages.
When cat /proc/pagetypeinfo, you can see the count of free mirrored blocks.

Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
---
 include/linux/mmzone.h | 9 +++++++++
 mm/page_alloc.c        | 3 +++
 mm/vmstat.c            | 3 +++
 3 files changed, 15 insertions(+)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 54d74f6..54e891a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -39,6 +39,9 @@ enum {
 	MIGRATE_UNMOVABLE,
 	MIGRATE_RECLAIMABLE,
 	MIGRATE_MOVABLE,
+#ifdef CONFIG_MEMORY_MIRROR
+	MIGRATE_MIRROR,
+#endif
 	MIGRATE_PCPTYPES,	/* the number of types on the pcp lists */
 	MIGRATE_RESERVE = MIGRATE_PCPTYPES,
 #ifdef CONFIG_CMA
@@ -69,6 +72,12 @@ enum {
 #  define is_migrate_cma(migratetype) false
 #endif
 
+#ifdef CONFIG_MEMORY_MIRROR
+#  define is_migrate_mirror(migratetype) unlikely((migratetype) == MIGRATE_MIRROR)
+#else
+#  define is_migrate_mirror(migratetype) false
+#endif
+
 #define for_each_migratetype_order(order, type) \
 	for (order = 0; order < MAX_ORDER; order++) \
 		for (type = 0; type < MIGRATE_TYPES; type++)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ebffa0e..6e4d79f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3216,6 +3216,9 @@ static void show_migration_types(unsigned char type)
 		[MIGRATE_UNMOVABLE]	= 'U',
 		[MIGRATE_RECLAIMABLE]	= 'E',
 		[MIGRATE_MOVABLE]	= 'M',
+#ifdef CONFIG_MEMORY_MIRROR
+		[MIGRATE_MIRROR]	= 'O',
+#endif
 		[MIGRATE_RESERVE]	= 'R',
 #ifdef CONFIG_CMA
 		[MIGRATE_CMA]		= 'C',
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 4f5cd97..d0323e0 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -901,6 +901,9 @@ static char * const migratetype_names[MIGRATE_TYPES] = {
 	"Unmovable",
 	"Reclaimable",
 	"Movable",
+#ifdef CONFIG_MEMORY_MIRROR
+	"Mirror",
+#endif
 	"Reserve",
 #ifdef CONFIG_CMA
 	"CMA",
-- 
2.0.0


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