On 2020/8/11 3:44, David Rientjes wrote:
> On Mon, 10 Aug 2020, wuyun...@huawei.com wrote:
>
>> From: Abel Wu <wuyun...@huawei.com>
>>
>> The commit below is incomplete, as it didn't handle the add_full() part.
>> commit a4d3f8916c65 ("slub: remove useless kmem_cache_debug() before
>> remove_full()")
>>
>> Signed-off-by: Abel Wu <wuyun...@huawei.com>
>> ---
>> mm/slub.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/slub.c b/mm/slub.c
>> index fe81773..0b021b7 100644
>> --- a/mm/slub.c
>> +++ b/mm/slub.c
>> @@ -2182,7 +2182,8 @@ static void deactivate_slab(struct kmem_cache *s,
>> struct page *page,
>> }
>> } else {
>> m = M_FULL;
>> - if (kmem_cache_debug(s) && !lock) {
>> +#ifdef CONFIG_SLUB_DEBUG
>> + if (!lock) {
>> lock = 1;
>> /*
>> * This also ensures that the scanning of full
>> @@ -2191,6 +2192,7 @@ static void deactivate_slab(struct kmem_cache *s,
>> struct page *page,
>> */
>> spin_lock(&n->list_lock);
>> }
>> +#endif
>> }
>>
>> if (l != m) {
>
> This should be functionally safe, I'm wonder if it would make sense to
> only check for SLAB_STORE_USER here instead of kmem_cache_debug(),
> however, since that should be the only context in which we need the
> list_lock for add_full()? It seems more explicit.
> .
>
Yes, checking for SLAB_STORE_USER here can also get rid of noising macros.
I will resend the patch later.
Thanks,
Abel
