Date: Tue, 11 Mar 2008 11:48:14 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Kip Macy <kip.macy@gmail.com> Cc: freebsd-fs@freebsd.org, Zaphod Beeblebrox <zbeeble@gmail.com>, current@freebsd.org, Thomas Vogt <freebsdlists@bsdunix.ch> Subject: Re: vm_thread_new: kstack allocation failed with many ZFS FS and NFSD Message-ID: <20080311094814.GF10374@deviant.kiev.zoral.com.ua> In-Reply-To: <b1fa29170803102124i445ab5b7j6f1a458f25c204c4@mail.gmail.com> References: <47D544B1.6070806@bsdunix.ch> <47D5D2B2.90202@FreeBSD.org> <5f67a8c40803101813k3a2b790dk57b67bc2d6f85d17@mail.gmail.com> <b1fa29170803102124i445ab5b7j6f1a458f25c204c4@mail.gmail.com>
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--f61P+fpdnY2FZS1u Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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@gmail.com> wr= ote: > > On Mon, Mar 10, 2008 at 8:30 PM, Kris Kennaway <kris@freebsd.org> wrote: > > > > > > > Your kernel has run out of memory. If you cannot tune kmem_size fur= ther > > > 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 task= s --- > > but I didn't realize there was a non-trivial cost (that is: a cost bey= ond > > the mount structure, root vnodes and whatnot)... >=20 > 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. --f61P+fpdnY2FZS1u Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (FreeBSD) iEYEARECAAYFAkfWVV0ACgkQC3+MBN1Mb4jxYACaAtwPk01KGJXSpe7Gu0LcUGuj VBEAn1jiS+kxdCHIg0VUaUw6wVixFSR3 =ukK4 -----END PGP SIGNATURE----- --f61P+fpdnY2FZS1u--
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