Here&#x27;s an example.  You have a 100MB C++ executable that needs 4GB for its own various purposes and 20GB of data that it&#x27;s serving.  The machine has 64GB of memory.  If you allocate 24.1GB of memory to the container for this service,  disable swap, and mlock the binary and the data files, nothing will go wrong.<p>On the same machine is a batch process which is reading a 1TB file and writing another 1TB file.  If your serving process was reliant on the OS page cache, it would find that its pages were routinely evicted in favor of the batch process.<p>You&#x27;re right about swap, that&#x27;s why only a crank would enable swap.  The moment at which swap was a reasonable solution was already behind us 20 years ago.