Re: [PATCH 1/4] try parent numa_node at first before using default

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On 7/9/07, Greg KH <greg@kroah.com> wrote:
> On Mon, Jul 09, 2007 at 05:52:34PM -0700, Christoph Lameter wrote:
> > It means that the node for the device is the same as the parent device.
> > F.e. if the parent device is a bus that is connected to node 4 then all
> > the devices hooked up to the bus are allocated on that node.
>
> Yes, but is someone setting the parent device node information properly?

> And this really needs some more changelog information please.  Why is
> this needed from how things are done today?

please check if you are happy with the changlog

----------------------------------------------------begin---------------------
For pci_device, pcibios_scan_root and pci_scan_root will call pci_device_add.
pci_device_add will call device_initialize and set_dev_node(&dev->dev,
pcibus_to_node(bus)).
other device such as netdev, and usb_device, set_dev_node is never be
used. So that field numa_node always is -1.

So for netdev, it will need to use dev->parent to get pci_device to
use it's numa_node. esp in netdev_alloc_skb()
not sure how other device such as infiniband do that.

Actually before patch
[PATCH 1/2] x86_64: get mp_bus_to_node as early
there is a bug about squence of bus->sysdata and using pcibus_to_node.
the numa_node of pci_dev->dev is never set correctly...always 0.

So some device have to use pcibus_to_node(to_pci_dev(dev)->bus) directly
such as dma_alloc_pages in arch/x86_64/kernel/pci-dma.c.
or hwif_to_node in include/linux/ide.h

with this patch, we could use device->numa_node direclty for all device.
-------------------------------------------------end-----------



YH