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

[Andrii Nakryiko]

On Thu, May 27, 2021 at 2:19 AM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
>
> On Thu, May 27, 2021 at 10:04:22AM +0100, Mel Gorman wrote:
> > What do you suggest as an alternative?
> >
> > I added Arnaldo to the cc as he tagged the last released version of
> > pahole (1.21) and may be able to tag a 1.22 with Andrii's fix for pahole
> > included.
> >
> > The most obvious alternative fix for this issue is to require pahole
> > 1.22 to set CONFIG_DEBUG_INFO_BTF but obviously a version 1.22 that works
> > needs to exist first and right now it does not. I'd be ok with this but
> > users of DEBUG_INFO_BTF may object given that it'll be impossible to set
> > the option until there is a release.
>
> Yes, disable BTF.  Empty structs are a very useful feature that we use
> in various places in the kernel.  We can't just keep piling hacks over
> hacks to make that work with a recent fringe feature.