On Sun, 20 Oct 2013 00:02:32 +0900
Masami Hiramatsu <masami.hiramatsu...@hitachi.com> wrote:
> (2013/10/18 23:27), Petr Mladek wrote:
> > We would like to use text_poke_bp in ftrace. It might be called also during
> > boot when the interupts are disabled. We need to enable them for syncing
> > the cores on each CPU. Otherwise, there might be a deadlock, see the
> > warning in "smp_call_function_many", kernel/smp.c:371.
>
> Steven, is this really needed?
> I think if this is the special use(e.g. boottime test),
> we'd better to run it after boot...
>
It's used to convert the calls to mcount to nops. But maybe a better
thing to do is to check if we only have a single CPU:
static void run_sync(void)
{
if (num_online_cpus() != 1)
on_each_cpu(do_sync_core, NULL, 1);
}
I believe that the only time we call this function with interrupts
disabled is before SMP is set up. Thus, the above change would handle
that case.
-- Steve
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