Here is one example of this problem being handled in the Linux kernel

Posted Jan 12, 2012 16:11 UTC (Thu) by PaulMcKenney (✭ supporter ✭, #9624)
In reply to: Denial of service via hash collisions by fuhchee
Parent article: Denial of service via hash collisions

Herbert Xu took this approach to solving this problem. His hash table will change the hash function at run time if any of the hash chains exceeds a specified length.

Run-time hash perturbation has also been used since the 1990s in net/sched/sch_sfq.c.