Re: [PATCH] mm/page_alloc: Work around a pahole limitation with zero-sized struct pagesets

[Mel Gorman]

On Wed, May 26, 2021 at 09:57:31AM -0700, Andrii Nakryiko wrote:
> > This patch checks for older versions of pahole and forces struct pagesets
> > to be non-zero sized as a workaround when CONFIG_DEBUG_INFO_BTF is set. A
> > warning is omitted so that distributions can update pahole when 1.22
> 
> s/omitted/emitted/ ?
> 

Yes.

> > is released.
> >
> > Reported-by: Michal Suchanek <msuchanek@xxxxxxx>
> > Reported-by: Hritik Vijay <hritikxx8@xxxxxxxxx>
> > Debugged-by: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
> > Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> > ---
> 
> Looks good! I verified that this does fix the issue on the latest
> linux-next tree, thanks!
> 

Excellent

> One question, should
> 
> Fixes: 5716a627517d ("mm/page_alloc: convert per-cpu list protection
> to local_lock")
> 
> be added to facilitate backporting?
> 

The git commit is not stable because the patch "mm/page_alloc: convert
per-cpu list protection to local_lock" is in Andrew's mmotm tree which is
quilt based. I decided not to treat the patch as a fix because the patch is
not wrong as such, it's a limitation of an external tool.  However, I would
expect both the problematic patch and the BTF workaround to go in during
the same merge window so backports to -stable should not be required.

> Either way:
> 
> Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> Tested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> 

Thanks!

-- 
Mel Gorman
SUSE Labs