From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhenzhong Duan Subject: Re: an issue with 'xm save' Date: Wed, 26 Sep 2012 16:48:42 +0800 Message-ID: <5062C16A.1020306@oracle.com> References: <505C3647.1030003@oracle.com> <20120921143430.GA3522@phenom.dumpdata.com> Reply-To: zhenzhong.duan@oracle.com Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============4398659321201040798==" Return-path: In-Reply-To: <20120921143430.GA3522@phenom.dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Konrad Rzeszutek Wilk Cc: Dan Magenheimer , Feng Jin , xen-devel List-Id: xen-devel@lists.xenproject.org This is a multi-part message in MIME format. --===============4398659321201040798== Content-Type: multipart/alternative; boundary="------------030209060703080401070101" This is a multi-part message in MIME format. --------------030209060703080401070101 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Konrad Rzeszutek Wilk wrote: > On Fri, Sep 21, 2012 at 05:41:27PM +0800, Zhenzhong Duan wrote: > >> Hi maintainers, >> >> I found there is an issue when 'xm save' a pvm guest. See below: >> >> When I do save then restore once, CPU(%) in xentop showed around 99%. >> When I do that second time, CPU(%) showed 199% >> >> top in dom0 showed: >> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND >> 20946 root 18 -2 10984 1284 964 S 19.8 0.3 0:48.93 block >> 4939 root 18 -2 10984 1288 964 S 19.5 0.3 1:34.68 block >> >> I could kill the block process, then all look normal again. >> > > What is the 'block' process? If you attach 'perf' to it do you get an idea > of what it is spinning at? > It's /etc/xen/scripts/block I add 'set -x' to /etc/xen/scripts/block, found it blocked at claim_lock. When domU was created first time, claim_lock/release_lock finished quickly, when 'xm save' was called, claim_lock spin in its own while loop. I can ensure no other domU create/save/etc happen when I test. > >> xen and xen-tools are both generated with xen-unstable. >> I tried xl, but it segfault. >> > > It segfaulted? When doing 'xl save' or 'xl resume'? Or just allocating > the guest? > When xl create vm.cfg > >> I also tried ovm3.1.1(xen-4.1.2-18.el5.1 and xen-tools-4.1.2-18.el5.1), >> can't reproduce. >> > > So the issue is only present with Xen-unstable? > Yes, I found in /etc/xen/scripts/locking.sh of ovm3.1.1, func claim_lock is quite different to xen-unstable Maybe this is why ovm3.1.1 work with save/restore. > Did you clear _any_ older Xen libraries/tools when you installed Xen-unstable? > No, I built xen and xen-tools on el5, then installed to ovm3.1.1 on other partition. thanks zduan --------------030209060703080401070101 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Konrad Rzeszutek Wilk wrote:

On Fri, Sep 21, 2012 at 05:41:27PM +0800, Zhenzhong Duan wrote:

Hi maintainers,

I found there is an issue when 'xm save' a pvm guest. See below:

When I do save then restore once, CPU(%) in xentop showed around 99%.
When I do that second time, CPU(%) showed 199%

top in dom0 showed:
    PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
   20946 root      18  -2 10984 1284  964 S 19.8  0.3   0:48.93 block
   4939 root      18  -2 10984 1288  964 S 19.5  0.3   1:34.68 block

I could kill the block process, then all look normal again.


What is the 'block' process? If you attach 'perf' to it do you get an idea
of what it is spinning at?

It's /etc/xen/scripts/block
I add 'set -x' to /etc/xen/scripts/block, found it blocked at claim_lock.
When domU was created first time, claim_lock/release_lock finished quickly,
when 'xm save' was called, claim_lock spin in its own while loop.
I can ensure no other domU create/save/etc happen when I test.

xen and xen-tools are both generated with xen-unstable.
I tried xl, but it segfault.


It segfaulted? When doing 'xl save'  or 'xl resume'? Or just allocating
the guest?

When xl create vm.cfg

I also tried ovm3.1.1(xen-4.1.2-18.el5.1 and xen-tools-4.1.2-18.el5.1),
can't reproduce.


So the issue is only present with Xen-unstable?

Yes, I found in /etc/xen/scripts/locking.sh of ovm3.1.1, func claim_lock is quite different to xen-unstable
Maybe this is why ovm3.1.1 work with save/restore.

Did you clear _any_ older Xen libraries/tools when you installed Xen-unstable?

No, I built xen and xen-tools on el5, then installed to ovm3.1.1 on other partition.
thanks
zduan --------------030209060703080401070101-- --===============4398659321201040798== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel --===============4398659321201040798==--