Re: Cannot boot xen DomU > 2.6.23.1

From: Jeremy Fitzhardinge
Date: Fri Jan 18 2008 - 02:32:58 EST


xming wrote:
The symptom is (with a lot of subjective judgment) when there is a lot (or
too quick) output on the console of the domU (hvc0 connected with either
"xm crea file.cfg -c" or "xm cons id") the whole PV domU hangs. It will
really hang at random places, sometimes right after init and sometime
after I logged in and just generate some ouput (on hvc0) like "find /". IIRC
I have never seen a hang before init.

OK, I misunderstood your original report to mean that something was complaining about "too much" output. You're saying that lots of console output seems to lock the domain.

I've had a report about heavy disk IO seems to lock up as well. Perhaps they're both related to high event rates. Do you think you could try an IO-intensive workload to see if you can get a similar lockup?

When the domain is locked up, what does /usr/lib/xen/bin/xenctx say?

Hm. Rather than backing out the structure-change patch, could you try this workaround:

diff -r be3ca4e0e19e arch/x86/xen/enlighten.c
--- a/arch/x86/xen/enlighten.c Thu Jan 17 14:25:07 2008 -0800
+++ b/arch/x86/xen/enlighten.c Thu Jan 17 16:37:42 2008 -0800
@@ -95,7 +95,7 @@ struct shared_info *HYPERVISOR_shared_in
*
* 0: not available, 1: available
*/
-static int have_vcpu_info_placement = 1;
+static int have_vcpu_info_placement = 0;

static void __init xen_vcpu_setup(int cpu)
{


Reverting the structure shape could cause crashes or random data corruption, but it has the side-effect of disabling the vpu_info structure placement mechanism. This patch disables it cleanly.

Thanks,
J
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