Re: [External] Re: [PATCH v4] mm: memcontrol: Add the missing numa_stat interface for cgroup v2

[Randy Dunlap <rdunlap@infradead.org>]

On 9/15/20 9:01 AM, Muchun Song wrote:
> On Tue, Sep 15, 2020 at 11:45 PM Randy Dunlap <rdunlap@infradead.org> wrote:
>>

>>> +static int __init numa_stats_init(void)
>>> +{
>>> +     int i;
>>> +
>>> +     for (i = 0; i < ARRAY_SIZE(numa_stats); i++) {
>>> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>> +             if (numa_stats[i].idx == NR_ANON_THPS)
>>> +                     numa_stats[i].ratio = HPAGE_PMD_SIZE;
>>> +#endif
>>> +     }
>>
>> Although the loop may be needed sometime in the future due to
>> other changes.. why couldn't it be like this for now?
> 
> The compiler is so smart, so there is nothing difference between
> them. I disassemble the numa_stats_init when
> !CONFIG_TRANSPARENT_HUGEPAGE.
> 
> Dump of assembler code for function numa_stats_init:
>    0xffffffff8273b061 <+0>: callq  0xffffffff81057490 <__fentry__>
>    0xffffffff8273b066 <+5>: xor    %eax,%eax
>    0xffffffff8273b068 <+7>: retq
> 

Of course!  Thanks.

>>
>>
>>> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>> +     for (i = 0; i < ARRAY_SIZE(numa_stats); i++) {
>>> +             if (numa_stats[i].idx == NR_ANON_THPS)
>>> +                     numa_stats[i].ratio = HPAGE_PMD_SIZE;
>>> +     }
>>> +#endif
>>
>>
>>> +
>>> +     return 0;
>>> +}
>>> +pure_initcall(numa_stats_init);


-- 
~Randy