NFS Mount and LARGE amounts of "INACT" memory

[Rick Macklem]

Larry Rosenman wrote:
> On 2015-06-17 07:26, Larry Rosenman wrote:
> > I have a 64G memory FreeBSD 11-CURRENT system that has a couple of
> > mounts to a FreeNAS (FreeBSD 9.3) system.
> > 
> > When my rsync from a different system to one of the NFS mounts
> > runs, I
> > get like 48G of Inactive memory that goes back to
> > free if I umount the share.
> > 
> > I'm wondering why this memory moves from ZFS ARC to INACT.
> > 
> > And, is this expected?
A wild ass guess would be yes. Assuming you are referring to the NFS
client (and not FreeNAS server) and guessing that rsync uses mmap'd
I/O...
- The pages will be associated with the file's vnode until that vnode
  is recycled. (mmap'd I/O can continue after the file is closed.)
  This could take a long time.
I am not knowledgible w.r.t. the VM subsystem, but I'm guessing that
there is some way for these pages to be reused if memory is limited?
(Hopefully someone with VM knowledge can comment on this?)

rick

> I've posted screenshots at:
> 
> http://www.lerctr.org/~ler/FreeBSD_inact/
> 
> 
> --
> Larry Rosenman                     http://www.lerctr.org/~ler
> Phone: +1 214-642-9640                 E-Mail: ler at lerctr.org
> US Mail: 108 Turvey Cove, Hutto, TX 78634-5688
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