On Wed, 25 Jan 2017 15:08:45 +0100
Petr Mladek <[email protected]> wrote:
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index 7180088cbb23..cc90c0a5ae21 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2158,19 +2158,18 @@ void console_unlock(void)
> }
>
> /*
> - * Console drivers are called under logbuf_lock, so
> - * @console_may_schedule should be cleared before; however, we may
> - * end up dumping a lot of lines, for example, if called from
> - * console registration path, and should invoke cond_resched()
> - * between lines if allowable. Not doing so can cause a very long
> - * scheduling stall on a slow console leading to RCU stall and
> - * softlockup warnings which exacerbate the issue with more
> - * messages practically incapacitating the system.
Why did you remove the comment about invoking cond_resched()? It's
still pertinent to the code, as there still exists a:
if (do_cond_resched)
cond_resched();
And the rational in the comment is still correct.
-- Steve
> + * Console drivers are called with interrupts disabled, so
> + * @console_may_schedule must be cleared before. The original
> + * value must be stored so that we could schedule between lines.
> + *
> + * console_trylock() is not able to detect the preemtible
> + * context reliably. Therefore the value must be stored before
> + * and cleared after the the "again" goto label.
> */
> do_cond_resched = console_may_schedule;
> +again:
> console_may_schedule = 0;
>
> -again:
> /*
> * We released the console_sem lock, so we need to recheck if
> * cpu is online and (if not) is there at least one CON_ANYTIME
