On Thu, May 27, 2021 at 2:19 AM Christoph Hellwig [off-list ref] wrote:

On Thu, May 27, 2021 at 10:04:22AM +0100, Mel Gorman wrote:

quoted

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.