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

["R. Tyler Ballance" <tyler@slide.com>]

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On Wed, 2009-01-07 at 16:48 -0800, Linus Torvalds wrote:
> 
> On Wed, 7 Jan 2009, R. Tyler Ballance wrote:
> >
> > 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.

This certainly corrected the issue, is there some magic
packedgitwindowsize that i should be looking at my own repository (our
internal one) in order to prevent the issue from occurring? 

Looking into .git/objects/pack, I think the two biggest pack files are
3.5G and 177MBG respectively :-!


Cheers
-- 
-R. Tyler Ballance
Slide, Inc.

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