On 2015/06/27 11:24, Xishi Qiu wrote:
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>
My fear about this approarch is that this may break something existing.
Now, when we add MIGRATE_MIRROR type, we'll hide attributes of pageblocks as
MIGRATE_UNMOVABOLE, MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE.
Logically, MIRROR attribute is independent from page mobility and this overwrites
will make some information lost.
Then,
---
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
I think
MIGRATE_MIRROR_UNMOVABLE,
MIGRATE_MIRROR_RECLAIMABLE,
MIGRATE_MIRROR_MOVABLE, <== adding this may need discuss.
MIGRATE_MIRROR_RESERVED, <== reserved pages should be maintained per mirrored/unmirrored.
should be added with the following fallback list.
/*
* MIRROR page range is defined by firmware at boot. The range is limited
* and is used only for kernel memory mirroring.
*/
[MIGRATE_UNMOVABLE_MIRROR] = {MIGRATE_RECLAIMABLE_MIRROR, MIGRATE_RESERVE}
[MIGRATE_RECLAIMABLE_MIRROR] = {MIGRATE_UNMOVABLE_MIRROR, MIGRATE_RESERVE}
Then, we'll not lose the original information of "Reclaiable Pages".
One problem here is whteher we should have MIGRATE_RESERVE_MIRROR.
If we never allow users to allocate mirrored memory, we should have MIGRATE_RESERVE_MIRROR.
But it seems to require much more code change to do that.
Creating a zone or adding an attribues to zones are another design choice.
Anyway, your patch doesn't takes care of reserved memory calculation at this point.
Please check setup_zone_migrate_reserve() That will be a problem.
Thanks,
-Kame
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",
--
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