[Crash-utility] [PATCH 4/5] xen: Try hard to get max_cpus value
This patch improves max_cpus value calculation. First
xen_hyper_get_cpu_info() tries to get it from nr_cpu_ids
variable. If nr_cpu_ids does not exist then it attempts
to read max_cpus variable. If it is not available estimate
max_cpus value on the base of cpumask_t size.
Signed-off-by: Daniel Kiper <daniel.kiper(a)oracle.com>
diff -Npru crash-6.1.0.orig/xen_hyper.c crash-6.1.0/xen_hyper.c
--- crash-6.1.0.orig/xen_hyper.c 2012-11-13 15:02:34.000000000 +0100
+++ crash-6.1.0/xen_hyper.c 2012-11-13 15:07:40.000000000 +0100
@@ -1883,13 +1883,28 @@ xen_hyper_get_uptime_hyper(void)
void
xen_hyper_get_cpu_info(void)
{
- ulong addr;
+ ulong addr, init_begin, init_end;
ulong *cpumask;
uint *cpu_idx;
int i, j, cpus;
XEN_HYPER_STRUCT_SIZE_INIT(cpumask_t, "cpumask_t");
- xht->max_cpus = XEN_HYPER_SIZE(cpumask_t) * 8;
+
+ if (symbol_exists("nr_cpu_ids"))
+ get_symbol_data("nr_cpu_ids", sizeof(uint), &xht->max_cpus);
+ else {
+ init_begin = symbol_value("__init_begin");
+ init_end = symbol_value("__init_end");
+ addr = symbol_value("max_cpus");
+
+ if (addr >= init_begin && addr < init_end)
+ xht->max_cpus = XEN_HYPER_SIZE(cpumask_t) * 8;
+ else {
+ get_symbol_data("max_cpus", sizeof(xht->max_cpus),
&xht->max_cpus);
+ if (XEN_HYPER_SIZE(cpumask_t) * 8 > xht->max_cpus)
+ xht->max_cpus = XEN_HYPER_SIZE(cpumask_t) * 8;
+ }
+ }
if (xht->cpumask) {
free(xht->cpumask);