From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Hesse Subject: Re: crash with CFS v4 and qemu/kvm (was: [patch] CFS scheduler, v4) Date: Tue, 24 Apr 2007 12:54:12 +0200 Message-ID: <200704241254.13791.mail@earthworm.de> References: <20070420140457.GA14017@elte.hu> <200704231128.23594.mail@earthworm.de> <20070423101839.GA19599@elte.hu> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0318400274==" Cc: Nick Piggin , kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, caglar-caicS1wCkhO6A22drWdTBw@public.gmane.org, Mike Galbraith , Peter Williams , Con Kolivas , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Gene Heskett , Willy Tarreau To: Ingo Molnar Return-path: In-Reply-To: <20070423101839.GA19599-X9Un+BFzKDI@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org --===============0318400274== Content-Type: multipart/signed; boundary="nextPart2143203.GxWJ45fF4u"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit --nextPart2143203.GxWJ45fF4u Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Monday 23 April 2007, Ingo Molnar wrote: > * Christian Hesse wrote: > > On Friday 20 April 2007, Ingo Molnar wrote: > > > i'm pleased to announce release -v4 of the CFS patchset. > > > > Hi Ingo, hi Avi, hi all, > > > > I'm trying to use kvm-20 with cfs v4 and get a crash: > > > > eworm@revo:~$ /usr/local/kvm/bin/qemu -snapshot > > /mnt/data/virtual/qemu/winxp.img kvm_run: failed entry, reason 7 > > kvm_run returned -8 > > > > It works (though it is a bit slow) if I start qemu with strace, so for > > me it looks like a race condition? > > hm. Can you work it around with: > > echo 0 > /proc/sys/kernel/sched_granularity_ns > > ? > > If yes then this is a wakeup race: some piece of code relies on the > upstream scheduler preempting the waker task immediately in 99% of the > cases. > > and you might want to test -v5 too which i released earlier today. It > has no bugfix in this area though, so it will likely still trigger this > race - but it will also hopefully be even more pleasant to use than -v4 > ;-) Hi Ingo, This was kvm's fault. It works perfectly now without modifications to the=20 scheduler. If anybody is interested in details please see the kvm mailing=20 list archives. =2D-=20 Regards, Chris --nextPart2143203.GxWJ45fF4u Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBGLeHVlZfG2c8gdSURAh+RAKDjPNqb6szSUmu1Dk6D8NesN2z+nQCfe+xl ScGfSVhCgdDFz4ZAH5lvNsA= =d9CV -----END PGP SIGNATURE----- --nextPart2143203.GxWJ45fF4u-- --===============0318400274== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ --===============0318400274== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ kvm-devel mailing list kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org https://lists.sourceforge.net/lists/listinfo/kvm-devel --===============0318400274==--