Re: [PATCH 1/1] hugetlb: fix CONFIG_PADATA dependency for non-SMP system

Muchun Song
2024-02-10T02:46:14Z

CC Jane, Daniel Jordan, Steffen as well in this thread.

> On Feb 8, 2024, at 10:39, Muchun Song <muchun.song@linux.dev> wrote:
> ﻿
>
>> On Feb 5, 2024, at 16:08, Gang Li <gang.li@linux.dev> wrote:
>>
>> ﻿On 2024/2/5 15:37, Muchun Song wrote:
>>> Actually, I did not get it. Why the above code cannot work? The above
>>> code already make it serialized in one call, right? What do I miss here?
>>> Thanks.
>>
>> PADATA consists of two distinct functionality:
>>
>> One part is `padata_do_multithreaded`, which disregards
>> order and simply divides tasks into several groups for parallel
>> execution. My patch use `padata_do_multithreaded`.
>
> OK. Since all users of PADATA of non-SMP case currently only use padata_do_multithreaded, it’s possible and easy to implement a variant of that in non-SMP case. It is not necessary to implement another functionality unless the only user of crypto/pcrypt.c does not depend on SMP in the future, at least now it’s dependent on SMP.
>
> Thanks.
>
>>
>> The other part is composed of a set of APIs that, while handling data in
>> an out-of-order parallel manner, can eventually return the data with
>> ordered sequence. Only `crypto/pcrypt.c` use them. I guess these APIs
>> are designed specifically for `crypto/pcrypt.c`.
>> ```
>> padata_alloc
>> padata_alloc_shell
>> padata_do_parallel
>> padata_do_serial
>> padata_free_shell
>> padata_free
>> ```