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

[Baolin Wang <baolin.wang@linux.alibaba.com>]

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>

>   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 */