Hi Timur,

On 08/06/2015 05:56 PM, Catalin Marinas wrote:

On Wed, Aug 05, 2015 at 05:46:03PM -0700, Timur Tabi wrote:

quoted

Catalin,

I know this patch is three years old, but I have a question about it:

On Fri, Sep 7, 2012 at 9:26 AM, Catalin Marinas [off-list ref] wrote:

quoted

+static void ipi_cpu_stop(unsigned int cpu)
+{
+       if (system_state == SYSTEM_BOOTING ||
+           system_state == SYSTEM_RUNNING) {
+               raw_spin_lock(&stop_lock);
+               pr_crit("CPU%u: stopping\n", cpu);
+               dump_stack();
+               raw_spin_unlock(&stop_lock);
+       }
+
+       set_cpu_online(cpu, false);
+
+       local_fiq_disable();
+       local_irq_disable();
+
+       while (1)
+               cpu_relax();
+}

Why do you display a message and dump the stack when a CPU is stopped?
  I ask because emergency_restart() calls this function, and so
whenever I want to do an "emergency" reboot, it dumps the stack for
each core.  On an ARM64 system with lots of cores, this produces a ton
of output.  That makes emergency_restart() almost useless.

This code was inherited from arch/arm which initially was always dumping
the stack but it later gained the system_state check. Unless it's useful
to anyone for debugging purposes, I'm ok with removing it.

Do you have patch for this one? My colleagues said that they met the
same problem :)

Thanks
Hanjun