Re: [PATCH 0/3] PM, vfs: use filesystem freezing instead of kthread freezer
From: Jiri Kosina
Date: Fri Oct 30 2015 - 15:40:39 EST
On Fri, 30 Oct 2015, Pavel Machek wrote:
> > I would say instead "no I/O is allowed from now on". Maybe that's an
> > overstatement, but I think it comes closer to the truth.
But that's what PM callbacks are for.
> Exactly. And I'm pretty sure hardware drivers do use kernel threads,
> and do I/O from them.
>
> LEDs are just one example
And why is that relevant? First, I don't see any freezable kthread in leds
class implementation whatsoever. Second, I am pretty sure that it's quite
unlikely to participate in filesystem I/O.
Sure, you need to suspend and resume the devices when going through
suspend. That's why led_suspend() exists. How would try_to_freeze() help
at all? That's basically just a fancy schedule() called at certain points.
--
Jiri Kosina
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/