On 10/23/12 18:52, Jeff Moyer wrote:
Bart Van Assche <bvanassche@xxxxxxx> writes:
Please keep in mind that a
single PCIe bus may have a minimal distance to more than one NUMA
node. See e.g. the diagram at the top of page 8 in
http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c03261871/c03261871.pdf
for a system diagram of a NUMA system where each PCIe bus has a
minimal distance to two different NUMA nodes.
That's an interesting configuration. I wonder what the numa_node sysfs
file contains for such systems--do you know? I'm not sure how we could
allow this to be user-controlled at probe time. Did you have a specific
mechanism in mind? Module parameters? Something else?
As far as I can see in drivers/pci/pci-sysfs.c the numa_node sysfs
attribute contains a single number, even for a topology like the one
described above.
With regard to user control of the numa node: I'm not sure how to solve
this in general. But for the ib_srp driver this should be easy to do:
SCSI host creation is triggered by sending a login string to a sysfs
attribute ("add_target"). It wouldn't take much time to add a parameter
to that login string that specifies the NUMA node.
Bart.
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