On Mon, 31 Aug 2015 01:58:40 -0400
Changsheng Liu <liuchangsheng@xxxxxxxxxx> wrote:
> From: Changsheng Liu <liuchangcheng@xxxxxxxxxx>
>
> After the user config CONFIG_MOVABLE_NODE and movable_node kernel option,
> When the memory is hot added, should_add_memory_movable() return 0
> because all zones including movable zone are empty,
> so the memory that was hot added will be added to the normal zone
> and the normal zone will be created firstly.
> But we want the whole node to be added to movable zone defaultly.
>
> So we change should_add_memory_movable(): if the user config
> CONFIG_MOVABLE_NODE and movable_node kernel option
> it will always return 1 and all zones is empty at the same time,
> so that the movable zone will be created firstly
> and then the whole node will be added to movable zone defaultly.
> If we want the node to be added to normal zone,
> we can do it as follows:
> "echo online_kernel > /sys/devices/system/memory/memoryXXX/state"
>
> If the memory is added to movable zone defaultly,
> the user can offline it and add it to other zone again.
> But if the memory is added to normal zone defaultly,
> the user will not offline the memory used by kernel.
>
> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Reviewed-by: Yasuaki Ishimatsu <yasu.isimatu@xxxxxxxxx>
> Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
> Reviewed-by: Xiaofeng Yan <yanxiaofeng@xxxxxxxxxx>
> Signed-off-by: Changsheng Liu <liuchangcheng@xxxxxxxxxx>
> Tested-by: Dongdong Fan <fandd@xxxxxxxxxx>
> ---
> mm/memory_hotplug.c | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 26fbba7..d1149ff 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1197,6 +1197,11 @@ static int should_add_memory_movable(int nid, u64 start, u64 size)
> unsigned long start_pfn = start >> PAGE_SHIFT;
> pg_data_t *pgdat = NODE_DATA(nid);
> struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE;
> + struct zone *normal_zone = pgdat->node_zones + ZONE_NORMAL;
> +
> + if (movable_node_is_enabled()
> + && (zone_end_pfn(normal_zone) <= start_pfn))
> + return 1;
If system boots up without movable_node, kernel behavior is changed by the patch.
And you syould consider other zone.
How about it. The patch is no build and test.
---
mm/memory_hotplug.c | 36 ++++++++++++++++++++++++++++++++----
1 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 6da82bc..321595d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1198,6 +1198,8 @@ static int check_hotplug_memory_range(u64 start, u64 size)
/*
* If movable zone has already been setup, newly added memory should be check.
* If its address is higher than movable zone, it should be added as movable.
+ * And if system boots up with movable_zone and added memory does not overlap
+ * other zone except for movable zone, the memory is added as movable.
* Without this check, movable zone may overlap with other zone.
*/
static int should_add_memory_movable(int nid, u64 start, u64 size)
@@ -1205,14 +1207,40 @@ static int should_add_memory_movable(int nid, u64 start, u64 size)
unsigned long start_pfn = start >> PAGE_SHIFT;
pg_data_t *pgdat = NODE_DATA(nid);
struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE;
+ struct zone *zone;
+ enum zone_type zt = ZONE_MOVABLE - 1;
+
+ /*
+ * If memory is added after ZONE_MOVALBE, the memory is managed as
+ * movable.
+ */
+ if (!zone_is_empty(movable_zone) &&
+ (movable_zone->zone_start_pfn <= start_pfn))
+ return 1;
- if (zone_is_empty(movable_zone))
+ if (!movable_node_is_enabled())
return 0;
- if (movable_zone->zone_start_pfn <= start_pfn)
- return 1;
+ /*
+ * Find enabled zone and check the added memory.
+ * If the memory is added after the enabled zone, the memory is
+ * managed as movable.
+ *
+ * If all zones are empty, the memory is also managed as movable.
+ */
+ for (; zt >= ZONE_DMA; zt--) {
+ zone = pgdat->node_zones + zt;
- return 0;
+ if (zone_is_empty(zone))
+ continue;
+
+ if (zone_end_pfn(zone) <= start_pfn)
+ return 1;
+ else
+ return 0;
+ }
+
+ return 1;
}
int zone_for_memory(int nid, u64 start, u64 size, int zone_default)
--
1.7.1
>
> if (zone_is_empty(movable_zone))
> return 0;
> --
> 1.7.1
>
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