From: Antony T Curtis <antony.t.curtis@ntlworld.com>
To: Norikatsu Shigemura <nork@FreeBSD.org>
Cc: Craig Boston <craig@xfoil.gank.org>,
jhb@FreeBSD.org, alc@FreeBSD.org, jeff@FreeBSD.org,
qemu-devel@nongnu.org, freebsd-current@FreeBSD.org,
Bakul Shah <bakul@BitBlocks.com>,
Juergen Lock <qemu-l@jelal.kn-bremen.de>
Subject: Re: [Qemu-devel] kqemu freebsd host smp problems?
Date: Sun, 10 Jul 2005 12:10:28 +0100 [thread overview]
Message-ID: <1120993828.46929.7.camel@pcgem.xiphis.org> (raw)
In-Reply-To: <200507100439.j6A4dlMK074874@sakura.ninth-nine.com>
On Sun, 2005-07-10 at 13:39 +0900, Norikatsu Shigemura wrote:
> On Sun, 03 Jul 2005 17:37:42 -0700
> Bakul Shah <bakul@BitBlocks.com> wrote:
> > Lock writes:
> > > Is kqemu and the freebsd wrapper smp aware? I just saw this panic
> > > report again,
> > > http://lists.freebsd.org/pipermail/freebsd-current/2005-May/050161.html
> > > and noticed it apparently happened with an smp kernel.
> > My guess is
> > .d_flags = D_NEEDGIANT,
> > needs to be added to the initializer of kqemu_cdevsw for the
> > freebsd-current case. AFAIK this flag ensures only one
> > thread can be in this driver at a time (but caveat emptor: I
> > don't play in the kernel these days).
>
> I confirmed that qemu on latest FreeBSD 6-current got more
> stability!!, but more little slowly:-( and a panic:-( too.
IMO, That flag is not the cause of the panics and that it should(tm)
work without requiring GIANT...
I think it is possible that the kqemu code is freeing a page without
unlocking it so that when another process does file IO which requires
pages to be allocated, attempts to wire those pages results in failure
and so a panic occurrs.
Perhaps if a different method for allocating memory rather than
contigmalloc/contigfree should be used by the kernel module.
<snip>
Offtopic - but am I the only person who has modified the if_tap driver
to permit opening by non-superuser?
--
Antony T Curtis, BSc. UNIX, Linux, *BSD, Networking
antony.t.curtis@ntlworld.com C++, J2EE, Perl, MySQL, Apache
IT Consultancy.
prev parent reply other threads:[~2005-07-10 11:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-03 23:07 [Qemu-devel] kqemu freebsd host smp problems? Juergen Lock
2005-07-04 0:37 ` Bakul Shah
2005-07-10 4:39 ` Norikatsu Shigemura
2005-07-10 11:10 ` Antony T Curtis [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1120993828.46929.7.camel@pcgem.xiphis.org \
--to=antony.t.curtis@ntlworld.com \
--cc=alc@FreeBSD.org \
--cc=bakul@BitBlocks.com \
--cc=craig@xfoil.gank.org \
--cc=freebsd-current@FreeBSD.org \
--cc=jeff@FreeBSD.org \
--cc=jhb@FreeBSD.org \
--cc=nork@FreeBSD.org \
--cc=qemu-devel@nongnu.org \
--cc=qemu-l@jelal.kn-bremen.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).