Re: [PATCH 2/2] crypto: qat - Enforce valid numa configuration.

[Tadeusz Struk <tadeusz.struk@intel.com>]

On 10/09/2014 04:23 AM, Prarit Bhargava wrote:
>>   int numa_node; /* NUMA node this device is close to */
>> > ...
> That's just bad english.  The numa node value (for pci devices) is
> read from the ACPI tables on the system and represents the node that
> the pci_dev is connected to.
> 
>> > };
>> >
>> > In case when there are two nodes and only node 0 has memory,
>> > dev->numa_node will be 0 even though the device will be connected to the
>> > pci root port of node 1.
> Your calculation completely falls apart and returns incorrect values when
> cpu hotplug is used or if there are multi-socket nodes (as was the case
> on the system that panicked), or if one uses the new cluster-on-die mode.

This calculation is sole for multi-socket configuration. This is why is
was introduced and what it was tested for.
There is no point discussing NUMA for single-socket configuration.
Single socket configurations are not NUMA. In this case dev->numa_node
is usually equal to NUMA_NO_NODE (-1) and adf_get_dev_node_id(pdev) will
always return 0;
Please confirm that, but I think the system it panicked on was a two
sockets system with only node 0 populated with memory and accelerator
plugged it to node 1 (phys_proc_id == 1).
In this case adf_get_dev_node_id(pdev) returned 1 and this was passed to
kzalloc_node(size, GFP_KERNEL, 1) and because there was no memory on
node 1 kzalloc_node() panicked.
This patch will make sure that this will not happen and that the
configuration will be optimal.