On Wed, 25 Jan 2017 15:08:45 +0100 Petr Mladek <pmladek@xxxxxxxx> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
