Re: how to recycle Inact memory more aggressively?

On Sun, 13 Mar 2016 18:33:20 -0700
Mark Johnston <markj_at_FreeBSD.org> wrote:

> On Sat, Mar 12, 2016 at 09:38:35AM +0100, Gary Jennejohn wrote:
> > In the course of the last year or so the behavior of the vm system
> > has changed in regard to how aggressively Inact memory is recycled.
> > 
> > My box has 8GB of memory.  At the moment I'm copying 100s of gigabytes
> > from one file system to another one.  
> 
> How exactly are you copying them? How large are the files you're
> copying? Which filesystems are in use?
> 

cp(1) from one UFS filesystem to another for backup.

The files I copied were all movies on the order of 2GB to 4GB.  So
it seems unlikely that cp(1) would try to mmap them.

The aggregate total was on the order of 300GB.

To add further detail - I tend to keep an eye on top while doing
copies like this.  Previously, I would observe Inact getting up to
about 6GB, but it would quickly drop on the order of 3GB and Free
would increase correspondingly.

Now I see that Inact is pretty much stuck at 6GB and Free only
grows by a few 100MB at best, which are quickly used up.

In the good old days large file copies would only cause a few
MB to be swapped out, but now its on the order of 100MB.


-- 
Gary Jennejohn