Re: [PATCH mm-new v2] mm/khugepaged: Factor out common logic in [scan,alloc]_sleep_millisecs_store()

Nico Pache
2025-10-21T17:42:46Z

On Tue, Oct 21, 2025 at 7:45 AM Leon Hwang <leon.hwang@linux.dev> wrote:
>
> Both scan_sleep_millisecs_store() and alloc_sleep_millisecs_store()
> perform the same operations: parse the input value, update their
> respective sleep interval, reset khugepaged_sleep_expire, and wake up
> the khugepaged thread.
>
> Factor out this duplicated logic into a helper function
> __sleep_millisecs_store(), and simplify both store functions.
>
> No functional change intended.
>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Reviewed-by: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Lance Yang <lance.yang@linux.dev>
> Signed-off-by: Leon Hwang <leon.hwang@linux.dev>

Nice cleanup!

Acked-by: Nico Pache <npache@redhat.com>

> ---
> v1 -> v2:
> - Simplify callsites of __sleep_millisecs_store() (per Lorenzo).
> - Collect Reviewed-by from Lorenzo, Zi and Lance - thanks!
> - https://lore.kernel.org/linux-mm/20251020115350.8175-1-leon.hwang@linux.dev/
>
> mm/khugepaged.c | 27 +++++++++++----------------
> 1 file changed, 11 insertions(+), 16 deletions(-)
>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 6f2ae2238b5b..5b7276bc14b1 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -129,9 +129,8 @@ static ssize_t scan_sleep_millisecs_show(struct kobject *kobj,
> return sysfs_emit(buf, "%u\n", khugepaged_scan_sleep_millisecs);
> }
>
> -static ssize_t scan_sleep_millisecs_store(struct kobject *kobj,
> - struct kobj_attribute *attr,
> - const char *buf, size_t count)
> +static ssize_t __sleep_millisecs_store(const char *buf, size_t count,
> + unsigned int *millisecs)
> {
> unsigned int msecs;
> int err;
> @@ -140,12 +139,19 @@ static ssize_t scan_sleep_millisecs_store(struct kobject *kobj,
> if (err)
> return -EINVAL;
>
> - khugepaged_scan_sleep_millisecs = msecs;
> + *millisecs = msecs;
> khugepaged_sleep_expire = 0;
> wake_up_interruptible(&khugepaged_wait);
>
> return count;
> }
> +
> +static ssize_t scan_sleep_millisecs_store(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + const char *buf, size_t count)
> +{
> + return __sleep_millisecs_store(buf, count, &khugepaged_scan_sleep_millisecs);
> +}
> static struct kobj_attribute scan_sleep_millisecs_attr =
> __ATTR_RW(scan_sleep_millisecs);
>
> @@ -160,18 +166,7 @@ static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj,
> struct kobj_attribute *attr,
> const char *buf, size_t count)
> {
> - unsigned int msecs;
> - int err;
> -
> - err = kstrtouint(buf, 10, &msecs);
> - if (err)
> - return -EINVAL;
> -
> - khugepaged_alloc_sleep_millisecs = msecs;
> - khugepaged_sleep_expire = 0;
> - wake_up_interruptible(&khugepaged_wait);
> -
> - return count;
> + return __sleep_millisecs_store(buf, count, &khugepaged_alloc_sleep_millisecs);
> }
> static struct kobj_attribute alloc_sleep_millisecs_attr =
> __ATTR_RW(alloc_sleep_millisecs);
> --
> 2.51.0
>