Delay executable info unloading to reduce churn

[bobrik]

We see a lot of the time spent loading and unloading the same executables:

Here instead of unloading immediately when the reference counter reaches zero, we delay it to allow possible reuse. This works great as most non-constantly-running things tend to run periodically (as opposed to once and then never again).

This is by no means final, but I'm opening it to kick off a conversation on whether this is the right approach.

See also: #532.

[bobrik]

I pushed an update with a 5 minute delay and a separate map. It is pretty effective in my production testing:

[christos68k]

I pushed an update with a 5 minute delay and a separate map. It is pretty effective in my production testing:

Thanks! How does memory use with a 5 minute delay look like?

[bobrik]

I can't see any visible difference. The long running stuff is big binaries, while the periodically running things are much smaller utilities, so it's hard for them to make a visible dent.