mm/hotplug: enable memory hotplug for non-lru movable pages
We had considered all of the non-lru pages as unmovable before commit
bda807d44454 ("mm: migrate: support non-lru movable page migration").
But now some of non-lru pages like zsmalloc, virtio-balloon pages also
become movable. So we can offline such blocks by using non-lru page
migration.
This patch straightforwardly adds non-lru migration code, which means
adding non-lru related code to the functions which scan over pfn and
collect pages to be migrated and isolate them before migration.
Signed-off-by: Yisheng Xie <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Hanjun Guo <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Reza Arbab <[email protected]>
Cc: Taku Izumi <[email protected]>
Cc: Vitaly Kuznetsov <[email protected]>
Cc: Xishi Qiu <[email protected]>
Cc: Yisheng Xie <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 5c4f484..7946375 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1531,10 +1531,10 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
}
/*
- * Scan pfn range [start,end) to find movable/migratable pages (LRU pages
- * and hugepages). We scan pfn because it's much easier than scanning over
- * linked list. This function returns the pfn of the first found movable
- * page if it's found, otherwise 0.
+ * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
+ * non-lru movable pages and hugepages). We scan pfn because it's much
+ * easier than scanning over linked list. This function returns the pfn
+ * of the first found movable page if it's found, otherwise 0.
*/
static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
{
@@ -1545,6 +1545,8 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
page = pfn_to_page(pfn);
if (PageLRU(page))
return pfn;
+ if (__PageMovable(page))
+ return pfn;
if (PageHuge(page)) {
if (page_huge_active(page))
return pfn;
@@ -1621,21 +1623,25 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
if (!get_page_unless_zero(page))
continue;
/*
- * We can skip free pages. And we can only deal with pages on
- * LRU.
+ * We can skip free pages. And we can deal with pages on
+ * LRU and non-lru movable pages.
*/
- ret = isolate_lru_page(page);
+ if (PageLRU(page))
+ ret = isolate_lru_page(page);
+ else
+ ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
if (!ret) { /* Success */
put_page(page);
list_add_tail(&page->lru, &source);
move_pages--;
- inc_node_page_state(page, NR_ISOLATED_ANON +
- page_is_file_cache(page));
+ if (!__PageMovable(page))
+ inc_node_page_state(page, NR_ISOLATED_ANON +
+ page_is_file_cache(page));
} else {
#ifdef CONFIG_DEBUG_VM
- pr_alert("removing pfn %lx from LRU failed\n", pfn);
- dump_page(page, "failed to remove from LRU");
+ pr_alert("failed to isolate pfn %lx\n", pfn);
+ dump_page(page, "isolation failed");
#endif
put_page(page);
/* Because we don't have big zone->lock. we should
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 41985aa..2d34cdb7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7227,8 +7227,9 @@ void *__init alloc_large_system_hash(const char *tablename,
* If @count is not zero, it is okay to include less @count unmovable pages
*
* PageLRU check without isolation or lru_lock could race so that
- * MIGRATE_MOVABLE block might include unmovable pages. It means you can't
- * expect this function should be exact.
+ * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
+ * check without lock_page also may miss some movable non-lru pages at
+ * race condition. So you can't expect this function should be exact.
*/
bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
bool skip_hwpoisoned_pages)
@@ -7284,6 +7285,9 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
if (skip_hwpoisoned_pages && PageHWPoison(page))
continue;
+ if (__PageMovable(page))
+ continue;
+
if (!PageLRU(page))
found++;
/*
