ATOP: vmcom / vmlim -> SWP is red

Question

in ATOP I'm getting a red alert like this: vmcom 76.3G | vmlim 49.8G

This is a value that is attached to the "SWP" (so "SWAP" is meant?)-line.

What does this mean and what can I do against it?

Solution

The atop man page helps explain what the numbers actually indicate.

Memory

If the committed virtual memory exceeds the limit ('vmcom' and 'vmlim' in the SWP-line), the SWP-line is colored due to overcommitting the system.

SWP

Swap occupation and overcommit info.

This line contains the total amount of swap space on disk ('tot') and the amount of free swap space ('free').

Furthermore the committed virtual memory space ('vmcom') and the maximum limit of the committed space ('vmlim', which is by default swap size plus 50% of memory size) is shown. The committed space is the reserved virtual space for all allocations of private memory space for processes. The kernel only verifies whether the committed space exceeds the limit if strict overcommit handling is configured (vm.overcommit_memory is 2).

https://linux.die.net/man/1/atop

It appears that this warning is nothing critical, but just a warning that memory pressure is getting high: https://unix.stackexchange.com/q/60474/32022

Comments

[orgoj]

See ATOP shows red line vmcom and vmlim. What does it mean?