Reserve more memory for background processes.

Our build uses more memory now, so I've increased the base footprint
of our build from 7GB to 10GB. This reduces the number of parallel VMs
we can launch on machines with 12GB RAM from 2 to 1.

BUG=chromium-os:28267, chrome-os-partner:8509
TEST=Test on buildbot with 12GB RAM and verify parallelism limit is 1 now
     rather than 2.

Change-Id: I33d53f59e08b561d1edf7c25068843af47978c2d
Reviewed-on: https://gerrit.chromium.org/gerrit/18904
Reviewed-by: Brian Harring <ferringb@chromium.org>
Commit-Ready: David James <davidjames@chromium.org>
Tested-by: David James <davidjames@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/18913
Reviewed-by: Ryan Cui <rcui@chromium.org>
1 file changed