> On Apr 24, 2020, at 11:12 AM, Waiman Long <longman@xxxxxxxxxx> wrote:
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 183ccc364ccf..255981180489 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -5567,13 +5567,30 @@ static ssize_t slab_attr_store(struct kobject *kobj,
> return -EIO;
>
> err = attribute->store(s, buf, len);
> -#ifdef CONFIG_MEMCG
> - if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
> - struct kmem_cache *c;
> +#ifdef CONFIG_MEMCG_KMEM
> + if (slab_state >= FULL && err >= 0 && is_root_cache(s) &&
> + !list_empty(&s->memcg_params.children)) {
> + struct kmem_cache *c, **pcaches;
> + int idx, max, cnt = 0;
> + size_t size = s->max_attr_size;
> + struct memcg_cache_array *arr;
> +
> + /*
> + * Make atomic update to s->max_attr_size.
> + */
> + do {
> + if (len <= size)
> + break;
> + } while (!try_cmpxchg(&s->max_attr_size, &size, len));
>
try_cmpxchg() is only available on x86.
mm/slub.c: In function ‘slab_attr_store’:
mm/slub.c:5613:13: error: implicit declaration of function ‘try_cmpxchg’; did you mean ‘xa_cmpxchg’? [-Werror=implicit-function-declaration]
} while (!try_cmpxchg(&s->max_attr_size, &size, len));
^~~~~~~~~~~
xa_cmpxchg
