Re: Public repro case! Re: [PATCH/RFC] Allow writing loose objects that are corrupted in a pack file

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jan 8, 2009, 00:48 UTC
Message-ID: <alpine.LFD.2.00.0901071644330.3283@localhost.localdomain>
In-Reply-To: <1231374514.8870.621.camel@starfruit>

On Wed, 7 Jan 2009, R. Tyler Ballance wrote:

Show 10 quoted lines

>
> My most esteemed colleague (Ken aka kb) who pointed out the memory issue
> was on the right path (I think), and I have a reproduction case you can
> try with your very own Linux kernel tree!
> 
> WOO!
> 
> I set ulimit -v really low (150M), and the operations I made got an
> mmap(2) fatal error, but there is a sweet spot that I found, see the
> transcript below.

This is indeed the packfile mapping. The sweet spot you found depends on how big the biggest two pack-files are, I do believe.

And if you do that

	[core]
		packedgitwindowsize = 64M

I think you'll find that it works. Of course, with a _really_ low ulimit, you'd need to make it even smaller, but at some point you start hitting other problems than the pack-file limits, ie just the simple fact that git wants and expects you to have a certain amount of memory available ;)

Can you cnfirm that your "reproducible" case starts working with that addition to your ~/.gitconfig? If so, the solution is pretty simple: we should just lower the default pack windowsize.

		Linus