Re: retiring laptop_mode? was Re: [PATCH] mm: vmscan: always allow writeback during memcg reclaim

Johannes Weiner
2025-12-17T19:59:23Z

On Tue, Dec 16, 2025 at 03:23:53PM -0800, Shakeel Butt wrote:
> On Tue, Dec 16, 2025 at 01:52:01PM -0500, Johannes Weiner wrote:

> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>

Thanks!

> > --- a/include/uapi/linux/sysctl.h
> > +++ b/include/uapi/linux/sysctl.h
> > @@ -183,7 +183,7 @@ enum
> > VM_LOWMEM_RESERVE_RATIO=20,/* reservation ratio for lower memory zones */
> > VM_MIN_FREE_KBYTES=21, /* Minimum free kilobytes to maintain */
> > VM_MAX_MAP_COUNT=22, /* int: Maximum number of mmaps/address-space */
> > - VM_LAPTOP_MODE=23, /* vm laptop mode */
> > +
>
> There are 8 earlier enums here with names like VM_UNUSED* along with
> the information on what were they. Should we have something similar for
> this one? Something like:
>
> VM_UNUSED10=23, /* was vm laptop mode */

The other enums in that file leave holes, the VM ones have a mix of
VM_UNUSED and holes. I don't think it matters either way since the
sysctl syscall has been removed and nothing new should be compiled
against the definitions in this file, right?