git-repack keeps running out of memory

I keep having git-repack run out of virtual memory ( 32 bit system ) when trying to repack my linux kernel repo. It keeps making it right up to 99% then barfing saying mmap failed: Cannot allocate memory.

I thought I could help this by limiting the pack size, and using --window-memory to limit the memory usage, but it still happens with this full command line:

git repack -a -d --max-pack-size=500m -f -F --depth=20 --window=250 --window-memory=500m

The key factor seems to be the --window... with 50 it works fine, but with 100 or more, even with the very low --window-memory limit, it crashes.

Quoted 11 lines · Phil Susi

I keep having git-repack run out of virtual memory ( 32 bit system ) when trying to repack my linux kernel repo. It keeps making it right up to 99% then barfing saying mmap failed: Cannot allocate memory.

I thought I could help this by limiting the pack size, and using --window-memory to limit the memory usage, but it still happens with this full command line:

git repack -a -d --max-pack-size=500m -f -F --depth=20 --window=250 --window-memory=500m

Quoted 3 lines

The key factor seems to be the --window... with 50 it works fine, but with 100 or more, even with the very low --window-memory limit, it crashes.

Unfortunately, that is totally expected. Window tells us to keep enough information to compare with that many objects in-core. I do not think max-pack-size would affect much.

It's more the --window-memory argument that is important here: it is supposed to prevent exactly this problem. I guess I tried adding the --max-pack-size as well on the off chance that it would help.

How many processors do you have? The window-memory is per-thread. Try with --threads=1.