When memory is onlined, we are only able to rezone from ZONE_MOVABLE to
ZONE_KERNEL, or from (ZONE_MOVABLE - 1) to ZONE_MOVABLE.
To be more flexible, use the following criteria instead; to online memory
from zone X into zone Y,
* Any zones between X and Y must be unused.
* If X is lower than Y, the onlined memory must lie at the end of X.
* If X is higher than Y, the onlined memory must lie at the start of X.
Add zone_can_shift() to make this determination.
Signed-off-by: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>
---
include/linux/memory_hotplug.h | 2 ++
mm/memory_hotplug.c | 42 +++++++++++++++++++++++++++++++++++-------
2 files changed, 37 insertions(+), 7 deletions(-)
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index adbef58..7bff0f9 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -284,5 +284,7 @@ extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
unsigned long map_offset);
extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
unsigned long pnum);
+extern int zone_can_shift(unsigned long pfn, unsigned long nr_pages,
+ enum zone_type target);
#endif /* __LINUX_MEMORY_HOTPLUG_H */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 6b4b005..b63cc28 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1032,6 +1032,37 @@ static void node_states_set_node(int node, struct memory_notify *arg)
node_set_state(node, N_MEMORY);
}
+int zone_can_shift(unsigned long pfn, unsigned long nr_pages,
+ enum zone_type target)
+{
+ struct zone *zone = page_zone(pfn_to_page(pfn));
+ enum zone_type idx = zone_idx(zone);
+ int i;
+
+ if (idx < target) {
+ /* pages must be at end of current zone */
+ if (pfn + nr_pages != zone_end_pfn(zone))
+ return 0;
+
+ /* no zones in use between current zone and target */
+ for (i = idx + 1; i < target; i++)
+ if (zone_is_initialized(zone - idx + i))
+ return 0;
+ }
+
+ if (target < idx) {
+ /* pages must be at beginning of current zone */
+ if (pfn != zone->zone_start_pfn)
+ return 0;
+
+ /* no zones in use between current zone and target */
+ for (i = target + 1; i < idx; i++)
+ if (zone_is_initialized(zone - idx + i))
+ return 0;
+ }
+
+ return target - idx;
+}
/* Must be protected by mem_hotplug_begin() */
int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
@@ -1057,13 +1088,10 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
!can_online_high_movable(zone))
return -EINVAL;
- if (online_type == MMOP_ONLINE_KERNEL &&
- zone_idx(zone) == ZONE_MOVABLE)
- zone_shift = -1;
-
- if (online_type == MMOP_ONLINE_MOVABLE &&
- zone_idx(zone) == ZONE_MOVABLE - 1)
- zone_shift = 1;
+ if (online_type == MMOP_ONLINE_KERNEL)
+ zone_shift = zone_can_shift(pfn, nr_pages, ZONE_NORMAL);
+ else if (online_type == MMOP_ONLINE_MOVABLE)
+ zone_shift = zone_can_shift(pfn, nr_pages, ZONE_MOVABLE);
zone = move_pfn_range(zone_shift, pfn, pfn + nr_pages);
if (!zone)
--
1.8.3.1
--
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