Re: [RFC][PATCH v6 1/2] printk: Make printk() completely async

From: Petr Mladek
Date: Tue Mar 22 2016 - 10:04:33 EST


On Tue 2016-03-22 14:11:06, Petr Mladek wrote:
> On Tue 2016-03-22 02:25:29, Sergey Senozhatsky wrote:
> > +static void wake_up_klogd_work_func(struct irq_work *irq_work)
> > +{
> > + int pending = __this_cpu_xchg(printk_pending, 0);
> > +
> > + if (pending & PRINTK_PENDING_OUTPUT) {
> > + /* If trylock fails, someone else is doing the printing */
> > + if (console_trylock())
> > + console_unlock();
>
> This is called from IRQ context and thus keeps the original problem
> for printk_deferred(). We should try to
> wake_up_process(printk_kthread) when allowed.
>
> if (pending & PRINTK_PENDING_OUTPUT) {
> if (printk_sync || !printk_kthread) {
> /* If trylock fails, someone else is printing. */
> if (console_trylock())
> console_unlock();
> } else {
> wake_up_process(printk_kthread);
> }
> }

Ah, this is in the 2nd patch. I am sorry for the noise.

Best Regards,
Petr