Re: [Qemu-devel] [PATCH 3/7] spapr: Refactor spapr_populate_memory()

[Alexey Kardashevskiy]

On 06/24/2014 03:40 AM, Nishanth Aravamudan wrote:
> On 21.06.2014 [13:06:53 +1000], Alexey Kardashevskiy wrote:
>> On 06/21/2014 08:55 AM, Nishanth Aravamudan wrote:
>>> On 16.06.2014 [17:53:49 +1000], Alexey Kardashevskiy wrote:
>>>> Current QEMU does not support memoryless NUMA nodes.
>>>> This prepares SPAPR for that.
>>>>
>>>> This moves 2 calls of spapr_populate_memory_node() into
>>>> the existing loop which handles nodes other than than
>>>> the first one.
>>>>
>>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>>> ---
>>>>  hw/ppc/spapr.c | 31 +++++++++++--------------------
>>>>  1 file changed, 11 insertions(+), 20 deletions(-)
>>>>
>>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>>>> index cb3a10a..666b676 100644
>>>> --- a/hw/ppc/spapr.c
>>>> +++ b/hw/ppc/spapr.c
>>>> @@ -689,28 +689,13 @@ static void spapr_populate_memory_node(void *fdt, 
>>>> int nodeid, hwaddr start,
>>>>
>>>>  static int spapr_populate_memory(sPAPREnvironment *spapr, void *fdt)
>>>>  {
>>>> -    hwaddr node0_size, mem_start, node_size;
>>>> +    hwaddr mem_start, node_size;
>>>>      int i;
>>>>
>>>> -    /* memory node(s) */
>>>> -    if (nb_numa_nodes > 1 && node_mem[0] < ram_size) {
>>>> -        node0_size = node_mem[0];
>>>> -    } else {
>>>> -        node0_size = ram_size;
>>>> -    }
>>>> -
>>>> -    /* RMA */
>>>> -    spapr_populate_memory_node(fdt, 0, 0, spapr->rma_size);
>>>> -
>>>> -    /* RAM: Node 0 */
>>>> -    if (node0_size > spapr->rma_size) {
>>>> -        spapr_populate_memory_node(fdt, 0, spapr->rma_size,
>>>> -                                   node0_size - spapr->rma_size);
>>>> -    }
>>>> -
>>>> -    /* RAM: Node 1 and beyond */
>>>> -    mem_start = node0_size;
>>>> -    for (i = 1; i < nb_numa_nodes; i++) {
>>>> +    for (i = 0, mem_start = 0; i < nb_numa_nodes; ++i) {
>>>> +        if (!node_mem[i]) {
>>>> +            continue;
>>>> +        }
>>>
>>> Doesn't this skip memoryless nodes? What actually puts the memoryless
>>> node in the device-tree?
>>
>> It does skip.
>>
>>> And if you were to put them in, wouldn't spapr_populate_memory_node()
>>> fail because we'd be creating two nodes with address@hidden where XXX is the
>>> same (starting address) for both?
>>
>> I cannot do this now - there is no way to tell from the command line
>> where I want NUMA node memory start from so I'll end up with multiple
>> nodes with the same name and QEMU won't start. When NUMA fixes reach
>> upstream, I'll try to work out something on top of that.
> 
> So in mst's tree, which I've rebased your patches, we have a struct
> defining each NUMA node, which has a size (and the index is the nodeid).
> I've got patches working that allow for sparse indexing, but I'm curious
> what you think we should do for the naming.


There should be no nodes for address@hidden in the device tree for memoryless
NUMA nodes so no problem with naming.


> I can send out the patches,
> with the caveat that architectures still need to fix the remaining
> issues for memoryless nodes?

? If we do not change the existing behavior and just extending it, why will
there be a problem?


-- 
Alexey