Plan is to take some time this August and revisit v6, hoping to move it
toward being production ready.

Today I studied the "Long Running Filter Process" documentation in
gitattributes(5), as well as the supplimental documentation in git about
the protocol they use. This interface was added to git after v6 mode was
implemented, and hopefully some of v6's issues can be fixed by using it in
some way. But I don't know how yet, it's not as simple as using this
interface as-is (it was designed for something different), but
finding a creative trick using it.

So far I have [this idea](http://git-annex.branchable.com/todo/Long_Running_Filter_Process/#comment-7c571c4ed26ce370ccd48db0a4aff4fc)
to explore. It's promising, might fix the worst of the problems.

Also, reading over all the notes in [[todo/smudge]], I finally
checked and yes, git doesn't require filters to consume all stdin anymore,
and when they don't consume stdin, git doesn't leak memory anymore either.
Which let me massively speed up `git add` in v6 repos. While before `git
add` of a gigabyte file made git grow to a gigabyte in memory and copied a
gigabyte through a pipe, it's now just as fast as `git annex add` in v5
mode is.

This work is supported by the NSF-funded DataLad project.
