Re: [PATCH v2 07/11] mm: shmem: drop has_transparent_hugepage() usage

[Luiz Capitulino <luizcap@redhat.com>]

On 2026-02-10 04:20, Baolin Wang wrote:
> 
> 
> On 2/10/26 6:14 AM, Luiz Capitulino wrote:
>> Shmem performs two kinds of has_transparent_hugepage() usage:
>>
>> 1. shmem_parse_one() and shmem_init(): since the calls to
>>     has_transparent_hugepage() are protected by #ifdef
>>     CONFIG_TRANSPARENT_HUGEPAGE, this actually checks if the CPU supports
>>     PMD-sized pages. This is irrelevant for shmem as it supports mTHP
>>
>> 2. shmem_parse_huge(): This is checking if THP is enabled and on
>>     architectures that implement has_transparent_hugepage(), this also
>>     checks if the CPU supports PMD-sized pages
>>
>> While it's necessary to check if CONFIG_TRANSPARENT_HUGEPAGE is enabled,
>> shmem can determine mTHP size support at folio allocation time.
>> Therefore, drop has_transparent_hugepage() usage while keeping the
>> CONFIG_TRANSPARENT_HUGEPAGE checks.
>>
>> Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
>> ---
> 
> Looks reasonable to me. Thanks.
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>

Thanks for your review. I didn't add your reviewed-by tag because I
updated the changelog. Also, sorry for the delay in resume my work on
this series.

> 
>>   mm/shmem.c | 7 +++----
>>   1 file changed, 3 insertions(+), 4 deletions(-)
>>
>> diff --git a/mm/shmem.c b/mm/shmem.c
>> index 79af5f9f8b90..32529586cd78 100644
>> --- a/mm/shmem.c
>> +++ b/mm/shmem.c
>> @@ -689,7 +689,7 @@ static int shmem_parse_huge(const char *str)
>>       else
>>           return -EINVAL;
>> -    if (!has_transparent_hugepage() &&
>> +    if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
>>           huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY)
>>           return -EINVAL;
>> @@ -4678,8 +4678,7 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
>>       case Opt_huge:
>>           ctx->huge = result.uint_32;
>>           if (ctx->huge != SHMEM_HUGE_NEVER &&
>> -            !(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
>> -              has_transparent_hugepage()))
>> +            !IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
>>               goto unsupported_parameter;
>>           ctx->seen |= SHMEM_SEEN_HUGE;
>>           break;
>> @@ -5463,7 +5462,7 @@ void __init shmem_init(void)
>>   #endif
>>   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>> -    if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY)
>> +    if (shmem_huge > SHMEM_HUGE_DENY)
>>           SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
>>       else
>>           shmem_huge = SHMEM_HUGE_NEVER; /* just in case it was patched */
>