On 2022/2/18 1:04, Vlastimil Babka wrote:
> On 2/17/22 11:44, Miaohe Lin wrote:
>> On 2022/2/17 17:23, Vlastimil Babka wrote:
>>> On 2/17/22 10:16, Miaohe Lin wrote:
>>>> Use helper function is_power_of_2() to check if KMALLOC_MIN_SIZE is power
>>>> of two. Minor readability improvement.
>>>>
>>>> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>>>
>>> We can try, but in case some compiler will no longer able to perform the
>>> check at build-time (although is_power_of_2() looks sufficiently trivial
>>> too), we'll have to revert it.
>>
>> I see. I checked the compiler in my env but there might be some compilers can't
>> perform the check at build-time.
>
> I'll add this to the slab tree and linux-next and we'll see if wider testing
> uncovers such compilers. Should be unlikely.
Many thanks! :)
>
>> Many thanks for your reply.
>>
>>>
>>>> ---
>>>> mm/slab_common.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/mm/slab_common.c b/mm/slab_common.c
>>>> index 23f2ab0713b7..6ee64d6208b3 100644
>>>> --- a/mm/slab_common.c
>>>> +++ b/mm/slab_common.c
>>>> @@ -807,7 +807,7 @@ void __init setup_kmalloc_cache_index_table(void)
>>>> unsigned int i;
>>>>
>>>> BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
>>>> - (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
>>>> + !is_power_of_2(KMALLOC_MIN_SIZE));
>>>>
>>>> for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
>>>> unsigned int elem = size_index_elem(i);
>>>
>>> .
>>>
>>
>
> .
>
