Re: [PATCH v2 1/5] prctl: extend PR_SET_THP_DISABLE to optionally exclude VM_HUGEPAGE

[Lorenzo Stoakes]

On Thu, Jul 31, 2025 at 02:12:44PM +0100, Usama Arif wrote:
>
>
> On 31/07/2025 13:40, Lorenzo Stoakes wrote:
> > On Thu, Jul 31, 2025 at 01:27:18PM +0100, Usama Arif wrote:
> > [snip]
> >> Acked-by: Usama Arif <usamaarif642@xxxxxxxxx>
> >> Tested-by: Usama Arif <usamaarif642@xxxxxxxxx>
> >> Cc: Jonathan Corbet <corbet@xxxxxxx>
> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> >> Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> >> Cc: Zi Yan <ziy@xxxxxxxxxx>
> >> Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
> >> Cc: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
> >> Cc: Nico Pache <npache@xxxxxxxxxx>
> >> Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
> >> Cc: Dev Jain <dev.jain@xxxxxxx>
> >> Cc: Barry Song <baohua@xxxxxxxxxx>
> >> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> >> Cc: Mike Rapoport <rppt@xxxxxxxxxx>
> >> Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
> >> Cc: Michal Hocko <mhocko@xxxxxxxx>
> >> Cc: Usama Arif <usamaarif642@xxxxxxxxx>
> >> Cc: SeongJae Park <sj@xxxxxxxxxx>
> >> Cc: Jann Horn <jannh@xxxxxxxxxx>
> >> Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> >> Cc: Yafang Shao <laoar.shao@xxxxxxxxx>
> >> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> >
> > You don't need to include these Cc's, Andrew will add them for you.
> >
> >> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
> >> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> >
> > Shouldn't this also be signed off by you? 2/5 and 3/5 has S-o-b for both
> > David and yourself?
> >
> > This is inconsistent at the very least.
> >
>
> Signed-off-by: Usama Arif <usamaarif642@xxxxxxxxx>
>
> The Ccs were added by David, and I didn't want to remove them.

Let's not add this noise on respins please, it makes review harder. No
other patch in the series, including ones by David, do it.

>
> >>
> >> ---
> >>
> >
> > Nothing below the --- will be included in the patch, so we can drop the
> > below, it's just noise that people can find easily if needed.
> >
> >> At first, I thought of "why not simply relax PR_SET_THP_DISABLE", but I
> >> think there might be real use cases where we want to disable any THPs --
> >> in particular also around debugging THP-related problems, and
> >> "never" not meaning ... "never" anymore ever since we add MADV_COLLAPSE.
> >> PR_SET_THP_DISABLE will also block MADV_COLLAPSE, which can be very
> >> helpful for debugging purposes. Of course, I thought of having a
> >> system-wide config option to modify PR_SET_THP_DISABLE behavior, but
> >> I just don't like the semantics.
> >
> > [snip]
> >
> >>
> >> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
> >
> > This S-o-b is weird, it's in a comment essentially. Let's drop that too
> > please.
>
>
> Everything below --- was added by David I believe to provide further explanation that
> doesn't need to be included in the commit message, and I didn't want to remove it
> or his 2nd sign-off, as its discarded anyways. Its useful info that can just be
> ignored.

Yup I get that, you've posted this several times now, anybody who needs it can
find it. Please remove on future respins to save me having to page through
noise.

The S-o-b was actively confusing, and this whole block of noise hid the
fact you got the S-o-b wrong on this patch.

Thanks