FreeBSD-10 and processes swapping out for no reason

[RW]

On Tue, 7 Jan 2014 20:16:42 +0400
Dmitry Sivachenko wrote:

> Hello!
> ardware.
> 
> I noticed that some of the processes on 10.0 boxes are marked as
> swapped out in top(1) output:


Do you have  vm.swap_idle_enabled set?

> I turned off swap:
> # swapinfo
> Device          1K-blocks     Used    Avail Capacity
> #
> 
> And state of these processes did not change: still second characted
> in state field of ps output is W, and top shows them in angles.

I've noticed that with swap_idle_enabled you can have processes shown
as swapped, but zero swap in use. If it's a bug it's a long standing
one.

My guess is that the vm system does something to the pages so that they
can be paged-out preferentially.