Diz logo no artigo:
This has no effect on Linux. man setrlimit says it used to work only in ancient versions.
A página do manual setrlimit diz:
RLIMIT_RSS Specifies the limit (in pages) of the process's resident set (the number of virtual pages resident in RAM). This limit has effect only in Linux 2.4.x, x < 30, and there affects only calls to madvise(2) specifying MADV_WILLNEED.
Então parou de funcionar em 2.4.30 .