居民集大小（RSS）限制无效

形成getrlimit手册页：

RLIMIT_RSSSpecifies the limit (in pages) of  the  process's  resident  set(the  number of virtual pages resident in RAM).  This limit onlyhas effect in Linux 2.4.x, x < 30, and there only affects  callsto madvise(2) specifying MADV_WILLNEED.

似乎Linux内核2.6不支持此功能。