Redis uses a memory layout that, unless the instance is completely idle, will make it very easy to touch every page even if there are just a few queries per sec

Redis uses a memory layout that, unless the instance is completely idle, will make it very easy to touch every page even if there are just a few queries per second. So fare in two years we never saw an instance where there was a latency problem because part of the dataset was swapped on disk by the OS. This is why we currently don't use mlockall().