Date: Sun, 10 Jul 2005 12:10:28 +0100 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? Message-ID: <1120993828.46929.7.camel@pcgem.xiphis.org> In-Reply-To: <200507100439.j6A4dlMK074874@sakura.ninth-nine.com> References: <20050704010715.A36404@saturn.kn-bremen.de> <200507040037.j640bg0v085158@gate.bitblocks.com> <200507100439.j6A4dlMK074874@sakura.ninth-nine.com>
next in thread | previous in thread | raw e-mail | index | archive | help
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.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1120993828.46929.7.camel>