Re: Cygwin can't handle huge packfiles?

[linux@horizon.com]

> Right now we LRU the pack files and evict older ones when we
> mmap too many, but the unit of eviction is the whole file, so it
> would not help the case like yours at all.  It might be possible
> to mmap only part of a packfile, but it would involve fairly
> major surgery to sha1_file.c.

The simplest solution seems to be to limit pack file size to a reasonable
fraction of a 32-bit address space.  Say, 0.5 G.

That should be a fairly straightforward hack to git-pack-objects.
It already emits two files; just make it emit more.

You can tweak the heurisitics to try to find a good break point: start
thinking about splitting the pack when you get to one size, but don't
force a break until you hit a harder limit as long as the deltas are
working well.

This can all be adjustable with a command line and/or config file option
to allow for the eventual demise of 32-bit systems.