4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
commit 464c7ffbcb164b2e5cebfa406b7fc6cdb7945344 upstream.
When scanning for movable pages, filter out Hugetlb pages if hugepage
migration is not supported. Without this we hit infinte loop in
__offline_pages() where we do
pfn = scan_movable_pages(start_pfn, end_pfn);
if (pfn) { /* We have movable pages */
ret = do_migrate_range(pfn, end_pfn);
goto repeat;
}
Fix this by checking hugepage_migration_supported both in
has_unmovable_pages which is the primary backoff mechanism for page
offlining and for consistency reasons also into scan_movable_pages
because it doesn't make any sense to return a pfn to non-migrateable
huge page.
This issue was revealed by, but not caused by 72b39cfc4d75 ("mm,
memory_hotplug: do not fail offlining too early").
Link: http://lkml.kernel.org/r/20180824063314.21981-1-aneesh.kumar@xxxxxxxxxxxxx
Fixes: 72b39cfc4d75 ("mm, memory_hotplug: do not fail offlining too early")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Reported-by: Haren Myneni <haren@xxxxxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 3 ++-
mm/page_alloc.c | 4 ++++
2 files changed, 6 insertions(+), 1 deletion(-)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1341,7 +1341,8 @@ static unsigned long scan_movable_pages(
if (__PageMovable(page))
return pfn;
if (PageHuge(page)) {
- if (page_huge_active(page))
+ if (hugepage_migration_supported(page_hstate(page)) &&
+ page_huge_active(page))
return pfn;
else
pfn = round_up(pfn + 1,
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7649,6 +7649,10 @@ bool has_unmovable_pages(struct zone *zo
* handle each tail page individually in migration.
*/
if (PageHuge(page)) {
+
+ if (!hugepage_migration_supported(page_hstate(page)))
+ goto unmovable;
+
iter = round_up(iter + 1, 1<<compound_order(page)) - 1;
continue;
}
