Re: [Xen-devel] Is: Contention in block script when doing guest saving. Was:Re: an issue with 'xm save'

[Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>]

On 2012-09-28 22:14, Ian Jackson wrote:
> Konrad Rzeszutek Wilk writes ("Is: Contention in block script when doing guest 
> saving. Was:Re: [Xen-devel] an issue with 'xm save'"):
> > On Fri, Sep 28, 2012 at 06:34:51PM +0800, Zhenzhong Duan wrote:
> > > After replace locking.sh with OVM's, it worked.
> > > But xen-tools evolved to use flock based locking currently. We can't
> > > revert back.
> > > It seems changeset 25595:497e2fe49455 bring the issue.
> > > Finally, I came with a small patch that workaround the issue.
> > Ian, any thoughts on how this can be fixed properly? The locking
> > is quite heavy and causes two scripts that do deal with blocks
> > to spin for a long time.
> The algorithm is not supposed to spin.  If it spins there is a bug, I
> think.
>
> Can you show me a transcript of the spinning happening with "set -x"
> in force ?
Hi Ian,
Attachment is part of xen-hotplug.log that will show the spin.
Original file is nearly 7G big. I fetch first 1000 lines.

Below is steps I did:
1. delete xen-hotplug.log
2. reboot dom0
3. add "set -x" to head of block script.
4.create first PV guest
5. save guest
6. get first 1000 lines from xen-hotplug.log

thanks
zduan

Attachment: xen-hotplug.log
Description: Text document

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