> > > The internal make command 'make rh-brew'/'make dist-brew' is failing with
> > >
> > > Processing 
> > > /home/prarit/git-kernel/kernel-ark/redhat/configs/kernel-aarch64-debug-fedora.config
> > >  ... Error: Mismatches found in configuration files
> > > Found CONFIG_FORCE_MAX_ZONEORDER=11 after generation, had 
> > > CONFIG_FORCE_MAX_ZONEORDER=13 in Source tree
> > >
> > > ARK commit f5ca593e1c2e ("configs: Adjust CONFIG_FORCE_MAX_ZONEORDER for
> > > Fedora") set this to 11, and follow-on ARK commit dd028d261347 ("[redhat]
> > > Sync up ARK's Fedora config tree with Fedora's dist-git") erroneously
> > > overwrote the value back to 13.
> > >
> > > Set CONFIG_FORCE_MAX_ZONEORDER back to 11 for aarch64.
> >
> > For reference the reason we have this disparity goes back to why
> > Fedora doesn't have 64K page sizes for aarch64. The reason is because
> > with 64K pages it makes CMA 512Mb rather than the 64Mb (which I think
> > can actually be 16) we have with 4K pages. I seem to remember its
> > something to do with CMA using large pages and with 64K page sizes
> > that makes the smallest large page to be 512Mb.
> >
> > Losing 512Mb is obviously fatal on devices with small amounts of RAM
> > like a bunch of the SBCs we support on Fedora so to support SBCs we
> > had to move to 4K pages until we got a proper fix for this. Related it
> > actually also affects RHEL for things like AWS images with small
> > amounts of memory so I suspect it would be useful to be fixed in the
> > RHEL use case too.
>
> Thanks Peter for the context!
>
> Mark should we enable this for ARK / RHEL-9?

I suspect 64K page size with the default CONFIG_FORCE_MAX_ZONEORDER
for that is what we want for RHEL, which I would think is what it
currently is.

The fix for both, which would allow Fedora to go back to 64K page
sizes and be the same as elX, would be the fix to allow smaller CMA
allocations.
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