[libvirt] [PATCH] Make nodeGetInfo report the correct number of NUMA nodes.
Chris Lalancette
clalance at redhat.com
Fri Mar 12 13:45:23 UTC 2010
On 03/12/2010 06:32 AM, Daniel Veillard wrote:
> On Thu, Mar 11, 2010 at 06:00:56PM -0500, Chris Lalancette wrote:
>> The nodeGetInfo code was always assuming that machine had a
>> single NUMA node, which is not correct. The good news is that
>> libnuma gives us this information pretty easily, so let's
>> properly report it.
>
> okay
>
>> NOTE: With recent hardware starting to support CPU hot-add
>> and hot-remove, both this code and the nodeCapsInitNUMA()
>> code are quickly going to become obsolete. We'll have to
>> think of a more dynamic solution for dealing with NUMA
>> nodes and CPUs that can come and go at will.
>
> well it makes little sense to refresh all the time,
> I would expect some kind of signal we can hook on to detect
> change in topology or capacities, though I don't see anything
> on signal.h for this
Well, it's actually not horrible to refresh all of the time. The
way we get this information is all in memory (from /proc or /sys),
so it's a very fast operation. That being said, if we can get
a signal when things change, and just react to that, that's probably
the best way to go. This stuff is all very new, so things are
still being put into place; we'll just have to figure out how to
be more dynamic in the future.
>
>> Signed-off-by: Chris Lalancette <clalance at redhat.com>
>> ---
>> src/nodeinfo.c | 6 +++++-
>> 1 files changed, 5 insertions(+), 1 deletions(-)
>>
>> diff --git a/src/nodeinfo.c b/src/nodeinfo.c
>> index 0748602..8d7e055 100644
>> --- a/src/nodeinfo.c
>> +++ b/src/nodeinfo.c
>> @@ -159,7 +159,11 @@ int linuxNodeInfoCPUPopulate(virConnectPtr conn, FILE *cpuinfo,
>>
>> nodeinfo->cpus = 0;
>> nodeinfo->mhz = 0;
>> - nodeinfo->nodes = nodeinfo->cores = 1;
>> + nodeinfo->cores = 1;
>> + if (numa_available() < 0)
>> + nodeinfo->nodes = 1;
>> + else
>> + nodeinfo->nodes = numa_max_node() + 1;
>>
>> /* NB: It is impossible to fill our nodes, since cpuinfo
>> * has no knowledge of NUMA nodes */
>
> ACK,
Thanks, I've pushed this now.
--
Chris Lalancette
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