Re: [PATCH x86/mm UPDATED] x86-64, NUMA: Fix distance table handling

[Yinghai Lu]

On Fri, Mar 11, 2011 at 10:19 AM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Hello,
>
> On Fri, Mar 11, 2011 at 10:02:41AM -0800, Yinghai Lu wrote:
>> > No, NUMA implementation can skip numa_set_distance() entirely if the
>> > distance is LOCAL_DISTANCE if nids are equal, REMOTE_DISTANCE
>> > otherwise.  In fact, any amdtopology configuraiton would behave this
>> > way, so it's incorrect to fill the table with LOCAL_DISTANCE.  You
>> > have to check the physnid mapping and build new table whether physical
>> > table exists or not.  Lack of physical distance table doesn't mean all
>> > nodes are LOCAL_DISTANCE.
>>
>> too bad. We should call numa_alloc_distance in amdtopology to set
>> default value in that array.
>
> I'm not following.  If there's no distance table, the distance is
> assumed to be LOCAL between the same node and REMOTE if the nodes are
> different, which is exactly the way it should be for those machines.
> Why is this bad and why would you allocate distance table for such
> configurations?

now even emulation have that distance array.

why keep it simple to make all path have that array?

Yinghai
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/