[V4 PATCH 26/26] memory_hotplug: handle empty zone when online_movable/online_kernel

Lai Jiangshan
2012-09-10T09:01:36Z

make online_movable/online_kernel can empty a zone
or can move memory to a empty zone.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
mm/memory_hotplug.c | 51 +++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e691076..1903850 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -216,8 +216,17 @@ static void resize_zone(struct zone *zone, unsigned long start_pfn,

zone_span_writelock(zone);

- zone->zone_start_pfn = start_pfn;
- zone->spanned_pages = end_pfn - start_pfn;
+ if (end_pfn - start_pfn) {
+ zone->zone_start_pfn = start_pfn;
+ zone->spanned_pages = end_pfn - start_pfn;
+ } else {
+ /*
+ * make it consist as free_area_init_core(),
+ * if spanned_pages = 0, then keep start_pfn = 0
+ */
+ zone->zone_start_pfn = 0;
+ zone->spanned_pages = 0;
+ }

zone_span_writeunlock(zone);
}
@@ -233,10 +242,19 @@ static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
set_page_links(pfn_to_page(pfn), zid, nid, pfn);
}

-static int move_pfn_range_left(struct zone *z1, struct zone *z2,
+static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
unsigned long start_pfn, unsigned long end_pfn)
{
+ int ret;
unsigned long flags;
+ unsigned long z1_start_pfn;
+
+ if (!z1->wait_table) {
+ ret = init_currently_empty_zone(z1, start_pfn,
+ end_pfn - start_pfn, MEMMAP_HOTPLUG);
+ if (ret)
+ return ret;
+ }

pgdat_resize_lock(z1->zone_pgdat, &flags);

@@ -250,7 +268,13 @@ static int move_pfn_range_left(struct zone *z1, struct zone *z2,
if (end_pfn <= z2->zone_start_pfn)
goto out_fail;

- resize_zone(z1, z1->zone_start_pfn, end_pfn);
+ /* use start_pfn for z1's start_pfn if z1 is empty */
+ if (z1->zone_start_pfn)
+ z1_start_pfn = z1->zone_start_pfn;
+ else
+ z1_start_pfn = start_pfn;
+
+ resize_zone(z1, z1_start_pfn, end_pfn);
resize_zone(z2, end_pfn, z2->zone_start_pfn + z2->spanned_pages);

pgdat_resize_unlock(z1->zone_pgdat, &flags);
@@ -263,10 +287,19 @@ out_fail:
return -1;
}

-static int move_pfn_range_right(struct zone *z1, struct zone *z2,
+static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
unsigned long start_pfn, unsigned long end_pfn)
{
+ int ret;
unsigned long flags;
+ unsigned long z2_end_pfn;
+
+ if (!z2->wait_table) {
+ ret = init_currently_empty_zone(z2, start_pfn,
+ end_pfn - start_pfn, MEMMAP_HOTPLUG);
+ if (ret)
+ return ret;
+ }

pgdat_resize_lock(z1->zone_pgdat, &flags);

@@ -280,8 +313,14 @@ static int move_pfn_range_right(struct zone *z1, struct zone *z2,
if (start_pfn >= z1->zone_start_pfn + z1->spanned_pages)
goto out_fail;

+ /* use end_pfn for z2's end_pfn if z2 is empty */
+ if (z2->zone_start_pfn)
+ z2_end_pfn = z2->zone_start_pfn + z2->spanned_pages;
+ else
+ z2_end_pfn = end_pfn;
+
resize_zone(z1, z1->zone_start_pfn, start_pfn);
- resize_zone(z2, start_pfn, z2->zone_start_pfn + z2->spanned_pages);
+ resize_zone(z2, start_pfn, z2_end_pfn);

pgdat_resize_unlock(z1->zone_pgdat, &flags);

--
1.7.1