[PATCH v3 06/10] mm: shmem: drop has_transparent_hugepage() usage

Luiz Capitulino
2026-04-08T20:23:34Z

Shmem uses has_transparent_hugepage() in the following ways:

- shmem_parse_one() and shmem_parse_huge(): Check if THP is built-in and
if the CPU supports PMD-sized pages

- shmem_init(): Since the CONFIG_TRANSPARENT_HUGEPAGE guard is outside
the code block calling has_transparent_hugepage(), the
has_transparent_hugepage() call is exclusively checking if the CPU
supports PMD-sized pages

While it's necessary to check if CONFIG_TRANSPARENT_HUGEPAGE is enabled
in all cases, 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>
---
mm/shmem.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index b40f3cd48961..6f8b20d77e07 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;

@@ -4664,8 +4664,7 @@ 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;
@@ -5451,7 +5450,7 @@ 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 */
--
2.53.0