Re: [Crash-utility] Re: [Xen-devel] crash can't analyze memory dumpfile of Xen
Itsuro ODA wrote:
Hi,
I found the root cause of this problem is that the value of "PERCPU_SHIFT"
was changed to 13 from 12.
The quick workaround is to apply the following patch to the crash command:
----------------------------------------------------------------------
--- xen_hyper_defs.h.org 2008-10-03 14:46:28.000000000 +0900
+++ xen_hyper_defs.h 2008-10-03 14:46:50.000000000 +0900
@@ -134,7 +134,7 @@
#endif
#if defined(X86) || defined(X86_64)
-#define XEN_HYPER_PERCPU_SHIFT 12
+#define XEN_HYPER_PERCPU_SHIFT 13
#define xen_hyper_per_cpu(var, cpu) \
((ulong)(var) + (((ulong)(cpu))<<XEN_HYPER_PERCPU_SHIFT))
#elif defined(IA64)
------------------------------------------------------------------------
I need to think the backword compatibility. I wonder how to determine
the value of "PERCPU_SHIFT". The change of "PERCPU_SHIFT" was made
at
a certain point of xen-unstable before xen-3.3 release. The xen version
number (3.3) can't use as key... I will consider more...
From the crash utility perspective, and looking at the RHEL5 xen sources
where these hypervisor definitions exist:
#define PERCPU_SIZE (1UL << PERCPU_SHIFT)
static void __init percpu_init_areas(void)
{
unsigned int i, data_size = __per_cpu_data_end - __per_cpu_start;
unsigned int first_unused;
BUG_ON(data_size > PERCPU_SIZE);
during initialization you could calculate the difference between the
__per_cpu_data_end and __per_cpu_start symbol values, and if it's more
than the original 4k size (12), then it must be 13.
Dave