Re: vm_thread_new: kstack allocation failed with many ZFS FS and NFSD

From: Kostik Belousov <kostikbel_at_gmail.com>
Date: Tue, 11 Mar 2008 11:48:14 +0200
On Mon, Mar 10, 2008 at 09:24:55PM -0700, Kip Macy wrote:
> On Mon, Mar 10, 2008 at 6:13 PM, Zaphod Beeblebrox <zbeeble_at_gmail.com> wrote:
> > On Mon, Mar 10, 2008 at 8:30 PM, Kris Kennaway <kris_at_freebsd.org> wrote:
> >
> >
> >  > Your kernel has run out of memory.  If you cannot tune kmem_size further
> >  > then it cannot handle this many ZFS filesystems.
> >
> >
> >  Roughly how much kernel memory does a filesystem use (even if inactive) ---
> >  or did you really mean something like too many pools?
> >
> >  The ZFS documentation encourages creating filesystems for everything.  I
> >  think my (rather beafy) laptop has 20 filesystems now for various tasks ---
> >  but I didn't realize there was a non-trivial cost (that is: a cost beyond
> >  the mount structure, root vnodes and whatnot)...
> 
> There may be kernel threads created for each file system. One way to
> look at it is that a process isn't that expensive, but FreeBSD
> probably couldn't cope very well with 5000 processes.

On the usual modern i386 hardware with usual load we easily handle
~30000 threads, with the top coming at around 50000 threads. The most
limiting factor, from my POV, is the kernel address space, since each
thread takes 3 pages for the kernel stack.

Received on Tue Mar 11 2008 - 08:48:34 UTC

This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:39:28 UTC