Hi Lorenzo, On 4/12/2017 1:04 PM, Lorenzo Pieralisi wrote: > On Sat, Apr 08, 2017 at 01:17:32PM -0400, Sinan Kaya wrote: >> On 12/31/1969 7:00 PM, linux-arm-kernel [mailto:linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Sergey Temerkhanov wrote: >>> int pcibus_to_node(struct pci_bus *bus) { >>> - return dev_to_node(&bus->dev); >>> + struct pci_config_window *cfg = bus->sysdata; >>> + struct acpi_device *adev = NULL; >>> + struct device *dev; >>> + >>> + if (!acpi_disabled) >>> + adev = to_acpi_device(cfg->parent); >>> + >> >> I see a problem here that NUMA node information is read from the >> parent device. PCI bus can have multiple levels of switches and >> bridges. The NUMA information is only present on the host bridge. >> >> This code only works if the endpoint is directly connected to the root >> port. > > That's not what this code does. This code retrieves the struct device > backing the ACPI device representing the PNP0A08 host bridge and its > dev->numa_node value (that was set in pci_acpi_scan_root()). pcibus_to_node() gets called from two places. The first place is pci_register_host_bridge() like you mentioned. The second place is pci_device_add(). pci_device_add() gets called for every single device that is getting added to the system. > > I am not a big fan of this. I wonder if we could not make it DT/ACPI > agnostic by simply setting the numa_node in the pci_bus->dev field, > and propagate it downstream a PCI hierarcy (as we do with sysdata) > in pci_alloc_child_bus(). Yeah, that's what I was going to ask next about how other arches solve this. Common solution to DT/ACPI is preferable as the issue exists in both places unless DT has some other mechanism hidden behind the scenes. > > This way pcibus_to_node() would become straightforward (ie as it > is now - provided the above is doable): > > dev_to_node(&bus->dev); > > This is suspiciously similar to the domain number song and dance > except that the NUMA node now is in the struct pci_bus->dev->numa_node > instead of struct pci_bus->domain_nr. I think this looks like the _CCA dance we are doing. > > Lorenzo > Sinan -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
