Re: Possible regression with cgroups in 3.11

From: Bjorn Helgaas
Date: Mon Nov 18 2013 - 15:39:37 EST


On Mon, Nov 18, 2013 at 11:29:32AM -0800, Yinghai Lu wrote:
> On Mon, Nov 18, 2013 at 10:14 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
> >> A bit of comment here would be nice but yeah I think this should work.
> >> Can you please also queue the revert of c2fda509667b ("workqueue:
> >> allow work_on_cpu() to be called recursively") after this patch?
> >> Please feel free to add my acked-by.
> >
> > OK, below are the two patches (Alex's fix + the revert) I propose to
> > merge. Unless there are objections, I'll ask Linus to pull these
> > before v3.13-rc1.
> >
> >
> >
> > commit 84f23f99b507c2c9247f47d3db0f71a3fd65e3a3
> > Author: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
> > Date: Mon Nov 18 10:59:59 2013 -0700
> >
> > PCI: Avoid unnecessary CPU switch when calling driver .probe() method
> >
> > If we are already on a CPU local to the device, call the driver .probe()
> > method directly without using work_on_cpu().
> >
> > This is a workaround for a lockdep warning in the following scenario:
> >
> > pci_call_probe
> > work_on_cpu(cpu, local_pci_probe, ...)
> > driver .probe
> > pci_enable_sriov
> > ...
> > pci_bus_add_device
> > ...
> > pci_call_probe
> > work_on_cpu(cpu, local_pci_probe, ...)
> >
> > It would be better to fix PCI so we don't call VF driver .probe() methods
> > from inside a PF driver .probe() method, but that's a bigger project.
> >
> > [bhelgaas: disable preemption, open bugzilla, rework comments & changelog]
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=65071
> > Link: http://lkml.kernel.org/r/CAE9FiQXYQEAZ=0sG6+2OdffBqfLS9MpoN1xviRR9aDbxPxcKxQ@xxxxxxxxxxxxxx
> > Link: http://lkml.kernel.org/r/20130624195942.40795.27292.stgit@xxxxxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
> > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Acked-by: Tejun Heo <tj@xxxxxxxxxx>
>
> Tested-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx>

Thanks, I added these and pushed my for-linus branch for -next to
pick up before I ask Linus to pull them.

Bjorn
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