On large systems, dumping state may cause time management to get stalled for so long a period that it wouldn't recover. Therefore alter the state dumping logic to - block each CPU as it prints rather than one CPU for a very long time - don't print useless data (e.g. the hypervisor context of the interrupt that is used for triggering the printing, but isn't part of the context that's actuall interesting. Signed-off-by: Jan Beulich --- 2010-05-04.orig/xen/arch/ia64/linux-xen/smp.c 2009-05-27 13:54:05.000000000 +0200 +++ 2010-05-04/xen/arch/ia64/linux-xen/smp.c 2010-05-04 13:22:27.000000000 +0200 @@ -189,7 +189,7 @@ handle_IPI (int irq, void *dev_id, struc * At this point the structure may be gone unless * wait is true. */ - (*func)(info); + (*func)(info ?: regs); /* Notify the sending CPU that the task is done. */ mb(); --- 2010-05-04.orig/xen/arch/x86/smp.c 2010-04-22 14:43:25.000000000 +0200 +++ 2010-05-04/xen/arch/x86/smp.c 2010-05-04 13:22:27.000000000 +0200 @@ -395,7 +395,7 @@ static void __smp_call_function_interrup if ( call_data.wait ) { - (*func)(info); + (*func)(info ?: get_irq_regs()); mb(); atomic_inc(&call_data.finished); } @@ -403,7 +403,7 @@ static void __smp_call_function_interrup { mb(); atomic_inc(&call_data.started); - (*func)(info); + (*func)(info ?: get_irq_regs()); } irq_exit(); --- 2010-05-04.orig/xen/common/keyhandler.c 2010-05-04 13:21:53.000000000 +0200 +++ 2010-05-04/xen/common/keyhandler.c 2010-05-04 13:22:27.000000000 +0200 @@ -71,20 +71,45 @@ static struct keyhandler show_handlers_k .desc = "show this message" }; -static void __dump_execstate(void *unused) +static cpumask_t dump_execstate_mask; + +static void __dump_execstate(void *_regs) { - dump_execution_state(); - printk("*** Dumping CPU%d guest state: ***\n", smp_processor_id()); + struct cpu_user_regs *regs = _regs; + unsigned int cpu = smp_processor_id(); + + if ( !guest_mode(regs) ) + { + printk("\n*** Dumping CPU%u host state: ***\n", cpu); + show_execution_state(regs); + } if ( is_idle_vcpu(current) ) - printk("No guest context (CPU is idle).\n"); + printk("No guest context (CPU%u is idle).\n", cpu); else + { + printk("*** Dumping CPU%u guest state (d%d:v%d): ***\n", + smp_processor_id(), current->domain->domain_id, + current->vcpu_id); show_execution_state(guest_cpu_user_regs()); + } + + cpu = cycle_cpu(cpu, dump_execstate_mask); + if ( cpu < NR_CPUS ) + { + cpu_clear(cpu, dump_execstate_mask); + on_selected_cpus(cpumask_of(cpu), __dump_execstate, NULL, 0); + } + else + { + printk("\n"); + + console_end_sync(); + watchdog_enable(); + } } static void dump_registers(unsigned char key, struct cpu_user_regs *regs) { - unsigned int cpu; - /* We want to get everything out that we possibly can. */ watchdog_disable(); console_start_sync(); @@ -92,21 +117,9 @@ static void dump_registers(unsigned char printk("'%c' pressed -> dumping registers\n", key); /* Get local execution state out immediately, in case we get stuck. */ - printk("\n*** Dumping CPU%d host state: ***\n", smp_processor_id()); - __dump_execstate(NULL); - - for_each_online_cpu ( cpu ) - { - if ( cpu == smp_processor_id() ) - continue; - printk("\n*** Dumping CPU%d host state: ***\n", cpu); - on_selected_cpus(cpumask_of(cpu), __dump_execstate, NULL, 1); - } - - printk("\n"); - - console_end_sync(); - watchdog_enable(); + cpus_andnot(dump_execstate_mask, cpu_online_map, + cpumask_of_cpu(smp_processor_id())); + __dump_execstate(regs); } static struct keyhandler dump_registers_keyhandler = { --- 2010-05-04.orig/xen/include/asm-ia64/linux-xen/asm/ptrace.h 2010-04-19 09:12:58.000000000 +0200 +++ 2010-05-04/xen/include/asm-ia64/linux-xen/asm/ptrace.h 2010-05-04 13:22:27.000000000 +0200 @@ -280,7 +280,7 @@ struct switch_stack { # define ia64_task_regs(t) (((struct pt_regs *) ((char *) (t) + IA64_STK_OFFSET)) - 1) # define ia64_psr(regs) ((struct ia64_psr *) &(regs)->cr_ipsr) #ifdef XEN -# define guest_mode(regs) (ia64_psr(regs)->cpl != 0) +# define guest_mode(regs) (ia64_psr(regs)->cpl && !ia64_psr(regs)->vm) # define guest_kernel_mode(regs) (ia64_psr(regs)->cpl == CONFIG_CPL0_EMUL) # define vmx_guest_kernel_mode(regs) (ia64_psr(regs)->cpl == 0) # define regs_increment_iip(regs) \