prevent hhvm perf-{pid}.map files
By default hhvm creates /tmp/perf-{pid}.map files, one for each hhvm process, and any time it crashes the file doesn't get cleaned up. These files are 10's of megabytes in size, and start eating into ram on a tmpfs. The files are used for perf profiling and are not needed for normal use. They can be prevented by adding -vEval.PerfPidMap=false
to the hhvm command line.
Reference: https://github.com/facebook/hhvm/issues/936