Re: [PATCH 2/3] mm/memory_hotplug: fix potential permanent lru cache disable

[David Hildenbrand]

On 21.08.21 11:42, Miaohe Lin wrote:
> 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.
>
> Fixes: d479960e44f2 ("mm: disable LRU pagevec during the migration temporarily")
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
>   mm/memory_hotplug.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index d986d3791986..9fd0be32a281 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -2033,6 +2033,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
>   	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",

Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>

As mentioned, this should be backported to stable.

--
Thanks,

David / dhildenb