Re: [PATCH 0/5] Suggested for PU: revision caching system to significantly speed up packing/walking

That might be useful, but I was thinking more of an "alternates"-like
mechanism between repos. So that the data is stored only once on disk
and in the disk cache, which is helpful for sites like kernel.org which
serve many similar repositories.

Oh, right.  Yes, that seems like it could work.  We'd have to be
careful that a shared cache slice wouldn' change (like in a fuse or
something), but other than that we could have something as simple as a
link.