[borman]

> Therefore, under memory pressure (especially if you set swappiness to zero), you will be preferentially swapping out your program code (because it is always clean) in preference to your program data.

Regarding systems with near 100% utilization, wouldn't it be a better advice to pin all executable code to memory via tmpfs (at system level) or mlockall() (application level)?

Encountered this case on some heavily-loaded batch data processing workers: at some point, client programs would slow down and generate random disk I/O (which in turn is detected by monitoring and throttled). Turned out, processes would go through major page faults at random moments in time, when their executable code pages are discarded from memory and subsequently re-read from disk.

[mnw21cam]

I'd love to have a configuration option on Linux that elevates the penalty for evicting executable pages, or just makes them non-discardable. I think it would help a lot.