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

From: Christoph Hellwig
Date: Thu May 27 2021 - 05:19:45 EST

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.