mm/memory_hotplug: fix potential permanent lru cache disable

If offline_pages failed after lru_cache_disable(), it forgot to do
lru_cache_enable() in error path.  So we would have lru cache disabled
permanently in this case.

Link: https://lkml.kernel.org/r/20210821094246.10149-3-linmiaohe@huawei.com
Fixes: d479960e44f2 ("mm: disable LRU pagevec during the migration temporarily")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Chris Goldsworthy <cgoldswo@codeaurora.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 8cb75b26ea4ff8805b5b22e85a212c8a4992df68..86c3af79e874e9ff986276e1b812d2892fdc863b 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1731,6 +1731,7 @@ failed_removal_isolated:
        undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
        memory_notify(MEM_CANCEL_OFFLINE, &arg);
 failed_removal_pcplists_disabled:
+       lru_cache_enable();
        zone_pcp_enable(zone);
 failed_removal:
        pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",