When I clone the kernel source, I encounter a fatal error.

[Hao Lee]

I have tried packedGitWindowSize, packedGitLimit, windowMemory,
packSizeLimit and other options, but it seems that cloning the whole
history still need a lot of memory and Git will be killed by OOM.

Finally, I find that I can clone the latest commit of all branches
with 'git clone --depth=1 --no-single-branch'. Although my local
repository doesn't have any history commits, I can still track remote
updates.

I hope my approach can help someone who want to have a lightweight repository.
Thanks for everyone's help !

Thanks,
Hao Lee.