From f1549c67f23f04a400cc056c54dd549b1433d221 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 4 Sep 2018 15:45:59 -0700 Subject: [PATCH] mm/hugetlb: filter out hugetlb pages if HUGEPAGE migration is not supported. 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@linux.ibm.com Fixes: 72b39cfc4d75 ("mm, memory_hotplug: do not fail offlining too early") Signed-off-by: Aneesh Kumar K.V Reported-by: Haren Myneni Acked-by: Michal Hocko Reviewed-by: Naoya Horiguchi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memory_hotplug.c | 3 ++- mm/page_alloc.c | 4 ++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 7deb49f69e276..785252397e35f 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1341,7 +1341,8 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) 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, diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3222193c46c67..65f2e6481c99e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7649,6 +7649,10 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count, * 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<