Tapdisk2 problem

Tapdisk2 problem

[Luís Silva]

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Hello,

I'm using both xen 4.0.1-rc5 and the latest pv_ops dom0 kernel (branch
xen/stable-2.6.32.x), but I'm having some problems with tapdisk2...

Basically, if I create a tap device (tapdisk2 -n
aio:/var/lib/libvirt/images/srv-001-ub1004.img), when I try to terminate
it by issuing "echo 1 > /sys/class/blktap2/blktap0/remove", the last
command hangs and tapdisk2 hangs using 100% cpu.

This happens both on manual device destruction and on virtual machine
shutdown. I don't know exactly what triggered this behaviour, but I
suspect kernel changes.

Can anyone confirm this behaviour?

Thanks,
Luís

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_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

Re: Tapdisk2 problem

[Luís Silva]

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Hello again,

I've tried updating the kernel as blktap has had some work on it, but
the problem remains. The up to date xen/stable-2.6.32.x still behaves as
described bellow. Also, I've tested this procedure against kernel
2.6.34.1 with Suse backported patches and the problem doesn't exist. I
haven't still tried updating xen to 4.0.1-rc6, but from the changelog I
don't see anything that could change this behaviour...

Is anyone with an up to date xen/stable-2.6.32.x kernel seeing this
problem or is it just I?

Thanks,
Luís

On Wed, 2010-08-04 at 15:04 +0100, Luís Silva wrote:

> Hello,
> 
> I'm using both xen 4.0.1-rc5 and the latest pv_ops dom0 kernel (branch
> xen/stable-2.6.32.x), but I'm having some problems with tapdisk2...
> 
> Basically, if I create a tap device (tapdisk2 -n
> aio:/var/lib/libvirt/images/srv-001-ub1004.img), when I try to
> terminate it by issuing "echo 1 > /sys/class/blktap2/blktap0/remove",
> the last command hangs and tapdisk2 hangs using 100% cpu.
> 
> This happens both on manual device destruction and on virtual machine
> shutdown. I don't know exactly what triggered this behaviour, but I
> suspect kernel changes.
> 
> Can anyone confirm this behaviour?
> 
> Thanks,
> Luís 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel



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_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

Re: Tapdisk2 problem

[Pasi Kärkkäinen]

On Sun, Aug 15, 2010 at 05:14:01PM +0100, Luís Silva wrote:
>    Hello again,
> 
>    I've tried updating the kernel as blktap has had some work on it, but the
>    problem remains. The up to date xen/stable-2.6.32.x still behaves as
>    described bellow. Also, I've tested this procedure against kernel 2.6.34.1
>    with Suse backported patches and the problem doesn't exist. I haven't
>    still tried updating xen to 4.0.1-rc6, but from the changelog I don't see
>    anything that could change this behaviour...
> 
>    Is anyone with an up to date xen/stable-2.6.32.x kernel seeing this
>    problem or is it just I?
> 

What's the previous xen/stable-2.6.32.x version that works for you?

-- Pasi


>    Thanks,
>    Luís
> 
>    On Wed, 2010-08-04 at 15:04 +0100, Luís Silva wrote:
> 
>      Hello,
> 
>      I'm using both xen 4.0.1-rc5 and the latest pv_ops dom0 kernel (branch
>      xen/stable-2.6.32.x), but I'm having some problems with tapdisk2...
> 
>      Basically, if I create a tap device (tapdisk2 -n
>      aio:/var/lib/libvirt/images/srv-001-ub1004.img), when I try to terminate
>      it by issuing "echo 1 > /sys/class/blktap2/blktap0/remove", the last
>      command hangs and tapdisk2 hangs using 100% cpu.
> 
>      This happens both on manual device destruction and on virtual machine
>      shutdown. I don't know exactly what triggered this behaviour, but I
>      suspect kernel changes.
> 
>      Can anyone confirm this behaviour?
> 
>      Thanks,
>      Luís
> 
>  _______________________________________________
>  Xen-devel mailing list
>  [1]Xen-devel@lists.xensource.com
>  [2]http://lists.xensource.com/xen-devel
> 
> References
> 
>    Visible links
>    1. mailto:Xen-devel@lists.xensource.com
>    2. http://lists.xensource.com/xen-devel



> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: Tapdisk2 problem

[Daniel Stodden]

On Wed, 2010-08-04 at 10:04 -0400, Luís Silva wrote:
> Hello,
> 
> I'm using both xen 4.0.1-rc5 and the latest pv_ops dom0 kernel (branch
> xen/stable-2.6.32.x), but I'm having some problems with tapdisk2...
> 
> Basically, if I create a tap device (tapdisk2 -n
> aio:/var/lib/libvirt/images/srv-001-ub1004.img), when I try to
> terminate it by issuing "echo 1 > /sys/class/blktap2/blktap0/remove",
> the last command hangs and tapdisk2 hangs using 100% cpu.
> 
> This happens both on manual device destruction and on virtual machine
> shutdown. I don't know exactly what triggered this behaviour, but I
> suspect kernel changes.
> 
> Can anyone confirm this behaviour?

Yes, with a broken userland. I thought Ian's dot-private patches to
ring.h made it into testing?

changeset:   21707:feee0abed6aa
user:        Keir Fraser <keir.fraser@citrix.com>
date:        Fri Jul 02 18:58:02 2010 +0100
summary:     blktap2: make protocol specific usage of shared sring explicit

The problem is that the kernel has those changes. What's going to happen
is that if tapdisk2 anticipates the ring 'message' at offset 17, not 16
as intended, it will fail to find/clear the ring message, while the
kernel will keep it spinning through select(), and that's what you're
seeing.

Keir, okay to just pull that stuff?

Daniel

Re: Tapdisk2 problem

[Keir Fraser]

On 15/08/2010 20:35, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:

> The problem is that the kernel has those changes. What's going to happen
> is that if tapdisk2 anticipates the ring 'message' at offset 17, not 16
> as intended, it will fail to find/clear the ring message, while the
> kernel will keep it spinning through select(), and that's what you're
> seeing.
> 
> Keir, okay to just pull that stuff?

What stuff to where?

 -- Keir

Re: Tapdisk2 problem

[Daniel Stodden]

On Sun, 2010-08-15 at 16:28 -0400, Keir Fraser wrote:
> On 15/08/2010 20:35, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:
> 
> > The problem is that the kernel has those changes. What's going to happen
> > is that if tapdisk2 anticipates the ring 'message' at offset 17, not 16
> > as intended, it will fail to find/clear the ring message, while the
> > kernel will keep it spinning through select(), and that's what you're
> > seeing.
> > 
> > Keir, okay to just pull that stuff?
> 
> What stuff to where?

changeset:   21707:feee0abed6aa
user:        Keir Fraser <keir.fraser@citrix.com>
date:        Fri Jul 02 18:58:02 2010 +0100
summary:     blktap2: make protocol specific usage of shared sring
explicit

Into 4.0.1. The offsets were broken by

changeset:   20267:e9366bed077e
user:        Keir Fraser <keir.fraser@citrix.com>
date:        Thu Oct 01 12:27:01 2009 +0100
summary:     VNIF: Using smart polling instead of event notification.

Not so good?

Daniel

Re: Tapdisk2 problem

[Keir Fraser]

On 15/08/2010 21:36, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:

> On Sun, 2010-08-15 at 16:28 -0400, Keir Fraser wrote:
>> On 15/08/2010 20:35, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:
>> 
>>> The problem is that the kernel has those changes. What's going to happen
>>> is that if tapdisk2 anticipates the ring 'message' at offset 17, not 16
>>> as intended, it will fail to find/clear the ring message, while the
>>> kernel will keep it spinning through select(), and that's what you're
>>> seeing.
>>> 
>>> Keir, okay to just pull that stuff?
>> 
>> What stuff to where?
> 
> changeset:   21707:feee0abed6aa
> user:        Keir Fraser <keir.fraser@citrix.com>
> date:        Fri Jul 02 18:58:02 2010 +0100
> summary:     blktap2: make protocol specific usage of shared sring
> explicit
> 
> Into 4.0.1.

Okay, done.

 K.

> The offsets were broken by
> 
> changeset:   20267:e9366bed077e
> user:        Keir Fraser <keir.fraser@citrix.com>
> date:        Thu Oct 01 12:27:01 2009 +0100
> summary:     VNIF: Using smart polling instead of event notification.
> 
> Not so good?

> Daniel
> 
> 

Re: Tapdisk2 problem

[Daniel Stodden]

On Sun, 2010-08-15 at 16:48 -0400, Keir Fraser wrote:
> On 15/08/2010 21:36, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:
> 
> > On Sun, 2010-08-15 at 16:28 -0400, Keir Fraser wrote:
> >> On 15/08/2010 20:35, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:
> >> 
> >>> The problem is that the kernel has those changes. What's going to happen
> >>> is that if tapdisk2 anticipates the ring 'message' at offset 17, not 16
> >>> as intended, it will fail to find/clear the ring message, while the
> >>> kernel will keep it spinning through select(), and that's what you're
> >>> seeing.
> >>> 
> >>> Keir, okay to just pull that stuff?
> >> 
> >> What stuff to where?
> > 
> > changeset:   21707:feee0abed6aa
> > user:        Keir Fraser <keir.fraser@citrix.com>
> > date:        Fri Jul 02 18:58:02 2010 +0100
> > summary:     blktap2: make protocol specific usage of shared sring
> > explicit
> > 
> > Into 4.0.1.
> 
> Okay, done.

Thanks!

Re: Tapdisk2 problem

[Michael Brade]

On Sunday 15 August 2010 23:54:43 Daniel Stodden wrote:
> On Sun, 2010-08-15 at 16:48 -0400, Keir Fraser wrote:
> > On 15/08/2010 21:36, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:
> > > On Sun, 2010-08-15 at 16:28 -0400, Keir Fraser wrote:
> > >> On 15/08/2010 20:35, "Daniel Stodden" <daniel.stodden@citrix.com> 
wrote:
> > >>> The problem is that the kernel has those changes. What's going to
> > >>> happen is that if tapdisk2 anticipates the ring 'message' at offset
> > >>> 17, not 16 as intended, it will fail to find/clear the ring message,
> > >>> while the kernel will keep it spinning through select(), and that's
> > >>> what you're seeing.
> > >>> 
> > >>> Keir, okay to just pull that stuff?
> > >> 
> > >> What stuff to where?
> > > 
> > > changeset:   21707:feee0abed6aa
> > > user:        Keir Fraser <keir.fraser@citrix.com>
> > > date:        Fri Jul 02 18:58:02 2010 +0100
> > > summary:     blktap2: make protocol specific usage of shared sring
> > > explicit
> > > 
> > > Into 4.0.1.
> > 
> > Okay, done.
> 
> Thanks!

Where can I find this change? I am using xen-4.0-testing.hg but the last chnage 
is a few days old?

Thanks,
-- 
Michael Brade;                                              KDE Developer
  |-mail: echo brade !#|tr -d "c oh"|s\e\d 's/e/\@/2;s/$/.org/;s/bra/k/2'
  °--web: http://www.behindkde.org/people/michaelb/

KDE 4: Beyond Your Expectations

Re: Tapdisk2 problem

[Pasi Kärkkäinen]

On Mon, Aug 16, 2010 at 12:07:35AM +0200, Michael Brade wrote:
> On Sunday 15 August 2010 23:54:43 Daniel Stodden wrote:
> > On Sun, 2010-08-15 at 16:48 -0400, Keir Fraser wrote:
> > > On 15/08/2010 21:36, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:
> > > > On Sun, 2010-08-15 at 16:28 -0400, Keir Fraser wrote:
> > > >> On 15/08/2010 20:35, "Daniel Stodden" <daniel.stodden@citrix.com> 
> wrote:
> > > >>> The problem is that the kernel has those changes. What's going to
> > > >>> happen is that if tapdisk2 anticipates the ring 'message' at offset
> > > >>> 17, not 16 as intended, it will fail to find/clear the ring message,
> > > >>> while the kernel will keep it spinning through select(), and that's
> > > >>> what you're seeing.
> > > >>> 
> > > >>> Keir, okay to just pull that stuff?
> > > >> 
> > > >> What stuff to where?
> > > > 
> > > > changeset:   21707:feee0abed6aa
> > > > user:        Keir Fraser <keir.fraser@citrix.com>
> > > > date:        Fri Jul 02 18:58:02 2010 +0100
> > > > summary:     blktap2: make protocol specific usage of shared sring
> > > > explicit
> > > > 
> > > > Into 4.0.1.
> > > 
> > > Okay, done.
> > 
> > Thanks!
> 
> Where can I find this change? I am using xen-4.0-testing.hg but the last chnage 
> is a few days old?
> 

It's in:
http://xenbits.xen.org/staging/xen-4.0-testing.hg

-- Pasi

Re: Tapdisk2 problem

[Michael Brade]

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On Monday 16 August 2010 08:56:16 Pasi Kärkkäinen wrote:
> On Mon, Aug 16, 2010 at 12:07:35AM +0200, Michael Brade wrote:
> > Where can I find this change? I am using xen-4.0-testing.hg but the last
> > chnage is a few days old?
> 
> It's in:
> http://xenbits.xen.org/staging/xen-4.0-testing.hg

Great, thanks! So whats the difference between

http://xenbits.xensource.com/xen-4.0-testing.hg
http://xenbits.xen.org/staging/xen-4.0-testing.hg
 
Is the former meant to be used at all?

Thanks,
-- 
Michael Brade;                                              KDE Developer
  |-mail: echo brade !#|tr -d "c oh"|s\e\d 's/e/\@/2;s/$/.org/;s/bra/k/2'
  °--web: http://www.behindkde.org/people/michaelb/

KDE 4: Beyond Your Expectations

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Re: Tapdisk2 problem

[Keir Fraser]

On 18/08/2010 18:17, "Michael Brade" <brade@kde.org> wrote:

> Great, thanks! So whats the difference between
> 
> http://xenbits.xensource.com/xen-4.0-testing.hg
> http://xenbits.xen.org/staging/xen-4.0-testing.hg
>  
> Is the former meant to be used at all?

Staging gets pushed there when it passes some automated tests.

 -- Keir

Re: Tapdisk2 problem

[Ian Jackson]

Keir Fraser writes ("Re: [Xen-devel] Tapdisk2 problem"):
> On 18/08/2010 18:17, "Michael Brade" <brade@kde.org> wrote:
> > Great, thanks! So whats the difference between
> > 
> > http://xenbits.xensource.com/xen-4.0-testing.hg
> > http://xenbits.xen.org/staging/xen-4.0-testing.hg
> >  
> > Is the former meant to be used at all?
> 
> Staging gets pushed there when it passes some automated tests.

Unfortunately those tests have been failing recently which is why the
main 4.0-testing tree is out of date.  We're working on finding and
fixing the problem, before releasing 4.0.1 !

(Also there is no meaningful difference in the domain name:
xenbits.xen.org is the new name for xenbits.xensource.com.)

Ian.

Re: Tapdisk2 problem

[Pasi Kärkkäinen]

On Sun, Aug 15, 2010 at 09:48:45PM +0100, Keir Fraser wrote:
> On 15/08/2010 21:36, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:
> 
> > On Sun, 2010-08-15 at 16:28 -0400, Keir Fraser wrote:
> >> On 15/08/2010 20:35, "Daniel Stodden" <daniel.stodden@citrix.com> wrote:
> >> 
> >>> The problem is that the kernel has those changes. What's going to happen
> >>> is that if tapdisk2 anticipates the ring 'message' at offset 17, not 16
> >>> as intended, it will fail to find/clear the ring message, while the
> >>> kernel will keep it spinning through select(), and that's what you're
> >>> seeing.
> >>> 
> >>> Keir, okay to just pull that stuff?
> >> 
> >> What stuff to where?
> > 
> > changeset:   21707:feee0abed6aa
> > user:        Keir Fraser <keir.fraser@citrix.com>
> > date:        Fri Jul 02 18:58:02 2010 +0100
> > summary:     blktap2: make protocol specific usage of shared sring
> > explicit
> > 
> > Into 4.0.1.
> 
> Okay, done.
> 

Btw will there be -rc7 now with these changes? 

-- Pasi



>  K.
> 
> > The offsets were broken by
> > 
> > changeset:   20267:e9366bed077e
> > user:        Keir Fraser <keir.fraser@citrix.com>
> > date:        Thu Oct 01 12:27:01 2009 +0100
> > summary:     VNIF: Using smart polling instead of event notification.
> > 
> > Not so good?
> 
> > Daniel
> > 
> > 
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: Tapdisk2 problem

[Keir Fraser]

On 16/08/2010 08:02, "Pasi Kärkkäinen" <pasik@iki.fi> wrote:

>>> changeset:   21707:feee0abed6aa
>>> user:        Keir Fraser <keir.fraser@citrix.com>
>>> date:        Fri Jul 02 18:58:02 2010 +0100
>>> summary:     blktap2: make protocol specific usage of shared sring
>>> explicit
>>> 
>>> Into 4.0.1.
>> 
>> Okay, done.
> 
> Btw will there be -rc7 now with these changes?

I'm not planning on doing an RC7. The two patches applied since RC6 are very
limited and obvious in their scope and impact. AFAIAC we are still on for
release at the end of the week.

 -- Keir