Bug#1003619: skimage: autopkgtest usually fails on armhf - out of memory

[Peter Green]

> The skimage autopkgtest usually, but not always, fails on armhf with several out-of-memory errors

BTW "out-of-memory" errors nearly always relate to address space rather than
actual memory. The Linux kernel overcommits memory by default, so actually
running out of memory is more likely to result in the OOM killer killing your
process than an out of memory error.

You can of course outright run out of address space (possibly because of leaky tests),
but more subtuly you can get issues with address space fragmentation, where there is
sufficient space available overall but the alocation algorithm can't find a block big
enough to satisfy your request.