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 15/11/2018 11.24, Jonathan Cameron wrote:
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!

Ingo Molnar had the same issue on another Threadripper system (Motherboard: MSI X399 SLI PLUS), so it is definitely not the only one.

Anyways:
  CPU: AMD Ryzen Threadripper 2950X
  Motherboard: ASRock X399 TAICHI

// Martin

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);








--
Kind regards,
Martin Hundebøll
Embedded Linux Consultant

+45 61 65 54 61
martin@xxxxxxxxxx

Geanix IVS
https://geanix.com
DK39600706



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