Re: [PATCH] ACPI: bind workqueues to CPU 0 to avoid SMI corruption

Bjorn Helgaas
2009-07-31T22:47:42Z

On Wednesday 29 July 2009 06:59:59 pm Zhang Rui wrote:
> On Thu, 2009-07-30 at 05:54 +0800, Bjorn Helgaas wrote:
> > On some machines, a software-initiated SMI causes corruption unless the
> > SMI runs on CPU 0. An SMI can be initiated by any AML, but typically it's
> > done in GPE-related methods that are run via workqueues, so we can avoid
> > the known corruption cases by binding the workqueues to CPU 0.
> >
> > References:
> > http://bugzilla.kernel.org/show_bug.cgi?id=13751
> > https://bugs.launchpad.net/bugs/157171
> > https://bugs.launchpad.net/bugs/157691
> >
> > Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
>
> Acked-by: Zhang Rui <rui.zhang@intel.com>

In addition to the reports above, I think it's likely this patch
will fix the problems reported below:

http://bugzilla.kernel.org/show_bug.cgi?id=13412
http://bugzilla.kernel.org/show_bug.cgi?id=11259
http://bugzilla.kernel.org/show_bug.cgi?id=12328
http://bugzilla.kernel.org/show_bug.cgi?id=12106

I think we should consider this patch for 2.6.31.

(Rafael, 13751 is on your "2.6.29 -> 2.6.30" regression list.
I actually think it's been around much longer than that, but
there seem to be many things that affect whether it manifests.)

Bjorn

> > ---
> > drivers/acpi/osl.c | 25 +++++++++++++++++++++++++
> > 1 files changed, 25 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> > index 7167071..5691f16 100644
> > --- a/drivers/acpi/osl.c
> > +++ b/drivers/acpi/osl.c
> > @@ -189,11 +189,36 @@ acpi_status __init acpi_os_initialize(void)
> > return AE_OK;
> > }
> >
> > +static void bind_to_cpu0(struct work_struct *work)
> > +{
> > + set_cpus_allowed(current, cpumask_of_cpu(0));
> > + kfree(work);
> > +}
> > +
> > +static void bind_workqueue(struct workqueue_struct *wq)
> > +{
> > + struct work_struct *work;
> > +
> > + work = kzalloc(sizeof(struct work_struct), GFP_KERNEL);
> > + INIT_WORK(work, bind_to_cpu0);
> > + queue_work(wq, work);
> > +}
> > +
> > acpi_status acpi_os_initialize1(void)
> > {
> > + /*
> > + * On some machines, a software-initiated SMI causes corruption unless
> > + * the SMI runs on CPU 0. An SMI can be initiated by any AML, but
> > + * typically it's done in GPE-related methods that are run via
> > + * workqueues, so we can avoid the known corruption cases by binding
> > + * the workqueues to CPU 0.
> > + */
> > kacpid_wq = create_singlethread_workqueue("kacpid");
> > + bind_workqueue(kacpid_wq);
> > kacpi_notify_wq = create_singlethread_workqueue("kacpi_notify");
> > + bind_workqueue(kacpi_notify_wq);
> > kacpi_hotplug_wq = create_singlethread_workqueue("kacpi_hotplug");
> > + bind_workqueue(kacpi_hotplug_wq);
> > BUG_ON(!kacpid_wq);
> > BUG_ON(!kacpi_notify_wq);
> > BUG_ON(!kacpi_hotplug_wq);
> >
> > --
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