Re: [PATCH 1/1] pci: Pick up the acpi numa node value if it is specified at the device level.

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On Wed, 14 Nov 2018 10:31:37 +0100
Martin Hundebøll <martin@xxxxxxxxxx> wrote:

> On 14/11/2018 09.57, Jonathan Cameron wrote:
> > On Tue, 13 Nov 2018 16:50:50 +0100
> > Martin Hundebøll <martin@xxxxxxxxxx> wrote:
> >   
> >> On 13/11/2018 15.49, Jonathan Cameron wrote:  
> >>> On Tue, 13 Nov 2018 11:26:54 +0100
> >>> Martin Hundebøll <martin@xxxxxxxxxx> wrote:
> >>>      
> >>>> On 13/11/2018 11.23, Jonathan Cameron wrote:  
> >>>>> On Tue, 13 Nov 2018 10:35:29 +0100
> >>>>> Martin Hundebøll <martin@xxxxxxxxxx> wrote:
> >>>>>         
> >>>>>> Hi Jonathan,
> >>>>>>
> >>>>>> On 13/11/2018 10.24, Jonathan Cameron wrote:  
> >>>>>>> On Mon, 12 Nov 2018 20:40:35 +0100
> >>>>>>> Martin Hundebøll <martin@xxxxxxxxxx> wrote:
> >>>>>>>            
> >>>>>>>> Hi Jonathan,
> >>>>>>>>
> >>>>>>>> I'm afraid this change made my system unbootable :(  
> >>>>>>> Hi Martin,
> >>>>>>>
> >>>>>>> Thanks for the report!  
> >>>>>>>>
> >>>>>>>> Testing both v4.20-rc1 and v4.20-rc2 resulting in nothing but a black
> >>>>>>>> screen, with no sign of life from either the keyboard or the network.
> >>>>>>>>
> >>>>>>>> Bisecting changes from v4.19 led me to this commit, and the system boots
> >>>>>>>> again with the change reverted.
> >>>>>>>>
> >>>>>>>> I know little about ACPI and PCI, so please tell the kind of debug/log
> >>>>>>>> you need.  
> >>>>>>> The ACPI DSDT would be where I would start.  Please send the output of
> >>>>>>> $cat /sys/firmware/acpi/tables/DSDT > DSDT.asl
> >>>>>>> (under whatever boots for you)
> >>>>>>>
> >>>>>>> If you want to look further yourself, you'll need to disassemble this using
> >>>>>>> the iASL compiler.  That is usually in a package called something like
> >>>>>>> acpica-tools or can be built from source from
> >>>>>>>
> >>>>>>> https://github.com/acpica/acpica
> >>>>>>>
> >>>>>>> iasl -d DSDT.asl
> >>>>>>>
> >>>>>>> This should generate a plain text file called DSDL.dsl.
> >>>>>>>
> >>>>>>> Send us that and hopefully it'll be obvious what is wrong!
> >>>>>>> Given we haven't had lots of reports, I'm going to guess there is something
> >>>>>>> unusual in the table, but we'll see.  
> >>>>>>
> >>>>>> Judging from the stderr output of the iasl command, additional ACPI
> >>>>>> tables were needed to do a full disassembly, so I ended up with:
> >>>>>>
> >>>>>> iasl -e SSDT1.asl SSDT2.asl SSDT3.asl SSDT4.asl SSDT5.asl SSDT6.asl
> >>>>>> SSDT7.asl  -d DSDT.asl
> >>>>>>
> >>>>>> I've attached the output.  
> >>>>>
> >>>>> So a couple of possibilities come to mind.
> >>>>>
> >>>>> 1) There are _PXM entries for
> >>>>> _SB.PCI0 - Looks like a root port. Bus number of 0
> >>>>> _SB.S0D1 - Looks like a root port. Bus number of 1
> >>>>> _SB.S0D2 - Looks like a root port. Bus number of 2
> >>>>> _SB.S0D3 - Looks like a root port. Bus number of 3
> >>>>>
> >>>>> covering nodes 0 - 3 which seems reasonable but the kernel log is recording that
> >>>>> no NUMA information was found - and you didn't attach an SRAT table along with the
> >>>>> others earlier so I'm going to guess there wasn't one?  
> >>>>
> >>>> No SRAT file in /sys/firmware/acpi/tables/, so I guess not.
> >>>>     
> >>>>> I suspect that will cause us all sorts of fun issues as I don't think the code
> >>>>> verifies the node exists - or at the very least there is one path that isn't.
> >>>>>
> >>>>> I'll fake up some equivalents on a machine here and see whether a few well placed
> >>>>> sanity checks will fix it.  
> >>>>
> >>>> I'll be happy to test patches, once we get there.  
> >>> Unfortunately I've not managed to replicate this yet.
> >>>
> >>> The code that this particular patch enabled shouldn't be effected by PXM entries
> >>> for the root ports (and doesn't seem to be on my system).
> >>>
> >>> Your log clearly states that PCI bus 40 is on numa node 1.
> >>> Could you check if that was logged prior to this patch?  
> >>
> >> Booting v4.18.16 shows the same in the kernel log (somewhat later in the
> >> boot process: 1.149584 vs 1.394208):
> >>
> >> [    1.149584] pci_bus 0000:40: on NUMA node 1  
> > 
> > Hi Martin,
> > 
> > Finally tracked down why I can't replicate.  A small difference between the arm64
> > paths and the x86 ones.  When arm64 doesn't find an SRAT it uses a dummy
> > numa table and one of the things that does is set the numa_off flag.
> > 
> > After that any call to acpi_get_node will pass the retrieved PXM (which may be
> > from a parent node in ACPI or anywhere above it in the tree) to acpi_map_pxm_to_node.
> > This is where things differ.
> > 
> > On X86 the numa_off flag isn't set so we get a potentially new numa node (with none
> > of the appropriate infrastructure being set up).  On arm64 we fail the first check
> > and drop out as numa_off is set. This results in a NUMA_NO_NODE being returned and
> > everything being fine.
> > 
> > So this is a question for the x86 people.  Is there reason to not set numa_off
> > at the end of the dummy_numa_init call?  Or is different handling needed?
> > 
> > Martin perhaps you can smoke test such a change by adding
> > numa_off = 1;
> > 
> > to the end of dummy_numa_init in arch/x86/mm/numa.c ?  
> 
> Hi Jonathan,
> 
> It seems like your on to something here: My workstation boots again with 
> 'numa_off = 1;' added to dummy_numa_init().
Cool. I'll send out a patch with your reported-by, feel free to add a tested-by
if you want to.

Right now this is buried in the thread, so won't get the visibility of a
fix patch.

I don't suppose you would mind sharing details of what the motherboard / system
is so that we can list it explicitly in the patch description.   It's probably
optimistic to think this is the only board out there with a bios broken like
this, but actual part numbers might save someone some time!

Jonathan

> 
> // Martin
> 
> > 
> > Thanks,
> > 
> > Jonathan  
> >>
> >> // Martin
> >>  
> >>> Thanks,
> >>>
> >>> Jonathan
> >>>      
> >>>>
> >>>> // Martin
> >>>>     
> >>>>> 2) We are successfully associating a lot of other stuff a little earlier
> >>>>> in the process for ACPI than previously so we 'might' cause a side effect where
> >>>>> data (that is presumably wrong) is now visible.
> >>>>>
> >>>>> This one looks less likely to me...
> >>>>>
> >>>>> 3) Something that someone who knows more about ACPI than me will spot!
> >>>>>
> >>>>> Thanks,
> >>>>>
> >>>>> Jonathan
> >>>>>
> >>>>> p.s. Rule one of ACPI. If it is possible to break it and still have common OSes
> >>>>> booting then people will manage to do so...
> >>>>>         
> >>>>>>
> >>>>>> Thanks,
> >>>>>> Martin
> >>>>>>        
> >>>>>>>
> >>>>>>> Thanks,
> >>>>>>>
> >>>>>>> Jonathan
> >>>>>>>            
> >>>>>>>>
> >>>>>>>> Thanks,
> >>>>>>>> Martin
> >>>>>>>>
> >>>>>>>> On 12/09/2018 17.21, Jonathan Cameron wrote:  
> >>>>>>>>> The ACPI specification allows you to provide _PXM entries for devices based
> >>>>>>>>> on their location on a particular bus.  Let us use that if it is provided
> >>>>>>>>> rather than just assuming it makes sense to put the device into the proximity
> >>>>>>>>> domain of the root.
> >>>>>>>>>
> >>>>>>>>> An example DSDT entry that will supply this is:
> >>>>>>>>>
> >>>>>>>>>        Device (PCI2)
> >>>>>>>>>        {
> >>>>>>>>>          Name (_HID, "PNP0A08") // PCI Express Root Bridge
> >>>>>>>>>          Name (_CID, "PNP0A03") // Compatible PCI Root Bridge
> >>>>>>>>>          Name(_SEG, 2) // Segment of this Root complex
> >>>>>>>>>          Name(_BBN, 0xF8) // Base Bus Number
> >>>>>>>>>          Name(_CCA, 1)
> >>>>>>>>>          Method (_PXM, 0, NotSerialized) {
> >>>>>>>>>            Return(0x00)
> >>>>>>>>>          }
> >>>>>>>>>
> >>>>>>>>> ...
> >>>>>>>>>          Device (BRI0) {
> >>>>>>>>>            Name (_HID, "19E51610")
> >>>>>>>>>            Name (_ADR, 0)
> >>>>>>>>>            Name (_BBN, 0xF9)
> >>>>>>>>>            Device (CAR0) {
> >>>>>>>>>              Name (_HID, "97109912")
> >>>>>>>>>              Name (_ADR, 0)
> >>>>>>>>>              Method (_PXM, 0, NotSerialized) {
> >>>>>>>>>                Return(0x02)
> >>>>>>>>>              }
> >>>>>>>>>            }
> >>>>>>>>>          }
> >>>>>>>>>        }
> >>>>>>>>>
> >>>>>>>>> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> >>>>>>>>> ---
> >>>>>>>>>       drivers/pci/pci-acpi.c | 5 +++++
> >>>>>>>>>       1 file changed, 5 insertions(+)
> >>>>>>>>>
> >>>>>>>>> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> >>>>>>>>> index 738e3546abb1..f2f5f0ddd60e 100644
> >>>>>>>>> --- a/drivers/pci/pci-acpi.c
> >>>>>>>>> +++ b/drivers/pci/pci-acpi.c
> >>>>>>>>> @@ -753,10 +753,15 @@ static void pci_acpi_setup(struct device *dev)
> >>>>>>>>>       {
> >>>>>>>>>       	struct pci_dev *pci_dev = to_pci_dev(dev);
> >>>>>>>>>       	struct acpi_device *adev = ACPI_COMPANION(dev);
> >>>>>>>>> +	int node;
> >>>>>>>>>       
> >>>>>>>>>       	if (!adev)
> >>>>>>>>>       		return;
> >>>>>>>>>       
> >>>>>>>>> +	node = acpi_get_node(adev->handle);
> >>>>>>>>> +	if (node != NUMA_NO_NODE)
> >>>>>>>>> +		set_dev_node(dev, node);
> >>>>>>>>> +	
> >>>>>>>>>       	pci_acpi_optimize_delay(pci_dev, adev->handle);
> >>>>>>>>>       
> >>>>>>>>>       	pci_acpi_add_pm_notifier(adev, pci_dev);
> >>>>>>>>>              
> >>>>>>>>           
> >>>>>>>
> >>>>>>>            
> >>>>>>        
> >>>>>
> >>>>>         
> >>>>     
> >>>
> >>>      
> >>  
> > 
> >   
> 





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