I largely agree. Although I do find the scenario of the kernel evicting mmapped pages causing performance degradation to be interesting and sounds plausible, b

I largely agree. Although I do find the scenario of the kernel evicting mmapped pages causing performance degradation to be interesting and sounds plausible, but I haven't personally witnessed this behavior. Where I see swap tend to get especially detrimental is with GCed processes. I've spent significant effort tracking down long GC pauses to getting blocked on swapped pages (although the software was not optimized and responsible as well and this was spinning rust). But in line with the article and your comments, this depends on engineering the system to have headroom. IIRC processes that use more than a NUMA node worth of memory also run into some issues with the OOM killer with swap disabled, unless set to interleaved on the NUMA policy. So that's another thing to look out for when dropping swap, although I forget exactly why it happens.