ANDROID: implement wrapper for reverse migration
Reverse migration is used to do the balancing the occupancy of memory
zones in a node in the system whose imabalance may be caused by
migration of pages to other zones by an operation, eg: hotremove and
then hotadding the same memory. In this case there is a lot of free
memory in newly hotadd memory which can be filled up by the previous
migrated pages(as part of offline/hotremove) thus may free up some
pressure in other zones of the node.
Upstream discussion: https://lore.kernel.org/all/ee78c83d-da9b-f6d1-4f66-934b7782acfb@codeaurora.org/
Change-Id: Ib3137dab0db66ecf6858c4077dcadb9dfd0c6b1c
Bug: 201263307
Signed-off-by: Charan Teja Reddy <quic_charante@quicinc.com>
diff --git a/mm/compaction.c b/mm/compaction.c
index bfc93da..a3c8ce4 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -758,6 +758,29 @@ isolate_freepages_range(struct compact_control *cc,
return pfn;
}
+unsigned long isolate_and_split_free_page(struct page *page,
+ struct list_head *list)
+{
+ unsigned long isolated;
+ unsigned int order;
+
+ if (!PageBuddy(page))
+ return 0;
+
+ order = buddy_order(page);
+ isolated = __isolate_free_page(page, order);
+ if (!isolated)
+ return 0;
+
+ set_page_private(page, order);
+ list_add(&page->lru, list);
+
+ split_map_pages(list);
+
+ return isolated;
+}
+EXPORT_SYMBOL_GPL(isolate_and_split_free_page);
+
/* Similar to reclaim, but different enough that they don't share logic */
static bool too_many_isolated(pg_data_t *pgdat)
{