lkml.org 
[lkml]   [2016]   [Apr]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] cpu/hotplug: handle unbalanced hotplug enable/disable
On Thu, 28 Apr 2016, Lianwei Wang wrote:
> On Wed, Apr 27, 2016 at 11:15 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> > On Wed, 27 Apr 2016, Lianwei Wang wrote:
> >> Yes. In our project, there is a kernel driver which register a pm
> >> notifier. On some conditions this pm notifier will return an error and
> >> abort the suspend process. The counter will be unbalanced in case it
> >> happened.
> >
> > So what? You wreckaged your driver, so you fix it and be done with it.
>
> Do you mean no pm_notifier callback can return an error or NOTIFY_BAD
> to abort the suspend process?
>
> It's not the driver issue. The driver return an error to abort the
> suspend process on purpose. Why do you think it is not allowed to
> return an error to abort suspend?
>
> The issue is very clear as described below.
> 1. How the issue happened?
> One of the pm notifier return error to abort suspend before
> cpu_hotplug_disable() is called on PM_SUSPEND_PREPARE.
>
> 2. What's the result?
> CPU hotplug work in a wrong way, or it doesn't work anymore. No way to
> recover it.
>
> 3. The root cause is that there is no any handling for the unbalanced
> cpu_hotplug_disable/enable calling. This patch add a protection for
> such issue.

Wrong. This is the symptom. The root cause is in #1. Therefor you are trying
to fix the symptom and not the root cause

> Anything not clear?

No.

I completely understand that you are tyring to put the cart before the horse.

Thanks,

tglx

\
 
 \ /
  Last update: 2016-04-29 03:01    [W:0.090 / U:1.680 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site