Re: [PATCH 1/9] mm/madvise: use is_memory_failure() from madvise_do_behavior()

Lorenzo Stoakes
2025-03-11T11:28:22Z

On Mon, Mar 10, 2025 at 10:23:10AM -0700, SeongJae Park wrote:
> To reduce redundant open-coded checks of CONFIG_MEMORY_FAILURE and
> MADV_{HWPOISON,SOFT_OFFLINE} in madvise_[un]lock(), is_memory_failure()
> has introduced. madvise_do_behavior() is still doing the same

NIT: 'is' introduced.

> open-coded check, though. Use is_memory_failure() instead.
>
> To avoid build failure on !CONFIG_MEMORY_FAILURE case, implement an
> empty madvise_inject_error() under the config. Also move the definition
> of is_memory_failure() inside #ifdef CONFIG_MEMORY_FAILURE clause for
> madvise_inject_error() definition, to reduce duplicated ifdef clauses.
>
> Signed-off-by: SeongJae Park <sj@kernel.org>

Good improvement, thanks!

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
> mm/madvise.c | 49 +++++++++++++++++++++++++++----------------------
> 1 file changed, 27 insertions(+), 22 deletions(-)
>
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 388dc289b5d1..c3ab1f283b18 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -1392,7 +1392,32 @@ static int madvise_inject_error(int behavior,
>
> return 0;
> }
> -#endif
> +
> +static bool is_memory_failure(int behavior)
> +{
> + switch (behavior) {
> + case MADV_HWPOISON:
> + case MADV_SOFT_OFFLINE:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +#else
> +
> +static int madvise_inject_error(int behavior,
> + unsigned long start, unsigned long end)
> +{
> + return 0;
> +}
> +
> +static bool is_memory_failure(int behavior)
> +{
> + return false;
> +}
> +
> +#endif /* CONFIG_MEMORY_FAILURE */
>
> static bool
> madvise_behavior_valid(int behavior)
> @@ -1569,24 +1594,6 @@ int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
> }
> #endif /* CONFIG_ANON_VMA_NAME */
>
> -#ifdef CONFIG_MEMORY_FAILURE
> -static bool is_memory_failure(int behavior)
> -{
> - switch (behavior) {
> - case MADV_HWPOISON:
> - case MADV_SOFT_OFFLINE:
> - return true;
> - default:
> - return false;
> - }
> -}
> -#else
> -static bool is_memory_failure(int behavior)
> -{
> - return false;
> -}
> -#endif
> -
> static int madvise_lock(struct mm_struct *mm, int behavior)
> {
> if (is_memory_failure(behavior))
> @@ -1640,10 +1647,8 @@ static int madvise_do_behavior(struct mm_struct *mm,
> unsigned long end;
> int error;
>
> -#ifdef CONFIG_MEMORY_FAILURE
> - if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
> + if (is_memory_failure(behavior))
> return madvise_inject_error(behavior, start, start + len_in);
> -#endif
> start = untagged_addr_remote(mm, start);
> end = start + len;
>
> --
> 2.39.5