Re: [PATCH] fs: touch up predicts in putname()

From: Jan Kara

Date: Thu Oct 30 2025 - 09:59:31 EST


On Wed 29-10-25 14:49:52, Mateusz Guzik wrote:
> 1. we already expect the refcount is 1.
> 2. path creation predicts name == iname
>
> I verified this straightens out the asm, no functional changes.
>
> Signed-off-by: Mateusz Guzik <mjguzik@xxxxxxxxx>

Looks sensible. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

Honza

> ---
>
> random annoyance i noticed while profiling
>
> fs/namei.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/namei.c b/fs/namei.c
> index ba29ec7b67c5..4692f25e7cd9 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -282,7 +282,7 @@ void putname(struct filename *name)
> return;
>
> refcnt = atomic_read(&name->refcnt);
> - if (refcnt != 1) {
> + if (unlikely(refcnt != 1)) {
> if (WARN_ON_ONCE(!refcnt))
> return;
>
> @@ -290,7 +290,7 @@ void putname(struct filename *name)
> return;
> }
>
> - if (name->name != name->iname) {
> + if (unlikely(name->name != name->iname)) {
> __putname(name->name);
> kfree(name);
> } else
> --
> 2.34.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR