I got this error while migrating huge svn repository to git using svn2git tool. I added below lines in my .git/config file and it started working:
[core]
repositoryformatversion = 0
filemode = false
bare = false
logallrefupdates = true
symlinks = false
ignorecase = true
hideDotFiles = dotGitOnly
packedGitLimit = 256m
packedGitWindowSize = 256m
longpaths = true
[http]
postBuffer = 524288000
[pack]
deltaCacheSize = 256m
packSizeLimit = 256m
windowMemory = 1024m
These settings are explained at the git-config man page.