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Re: [Qemu-ppc] [Qemu-devel] [PATCH for 2.13 v3 1/2] spapr: Add ibm, max-
From: |
Serhii Popovych |
Subject: |
Re: [Qemu-ppc] [Qemu-devel] [PATCH for 2.13 v3 1/2] spapr: Add ibm, max-associativity-domains property |
Date: |
Tue, 17 Apr 2018 19:26:22 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:51.0) Gecko/20100101 Firefox/51.0 |
David Gibson wrote:
> On Tue, Apr 17, 2018 at 09:28:42AM +0530, Bharata B Rao wrote:
>> On Mon, Apr 16, 2018 at 07:47:29PM +0300, Serhii Popovych wrote:
>>> Bharata B Rao wrote:
>>>> On Wed, Apr 11, 2018 at 02:41:59PM -0400, Serhii Popovych wrote:
>>>>> Now recent kernels (i.e. since linux-stable commit a346137e9142
>>>>> ("powerpc/numa: Use ibm,max-associativity-domains to discover possible
>>>>> nodes")
>>>>> support this property to mark initially memory-less NUMA nodes as
>>>>> "possible"
>>>>> to allow further memory hot-add to them.
>>>>>
>>>>> Advertise this property for pSeries machines to let guest kernels detect
>>>>> maximum supported node configuration and benefit from kernel side change
>>>>> when hot-add memory to specific, possibly empty before, NUMA node.
>>>>>
>>>>> Signed-off-by: Serhii Popovych <address@hidden>
>>>>> ---
>>>>> hw/ppc/spapr.c | 10 ++++++++++
>>>>> 1 file changed, 10 insertions(+)
>>>>>
>>>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>>>>> index a81570e..c05bbad 100644
>>>>> --- a/hw/ppc/spapr.c
>>>>> +++ b/hw/ppc/spapr.c
>>>>> @@ -910,6 +910,13 @@ static void spapr_dt_rtas(sPAPRMachineState *spapr,
>>>>> void *fdt)
>>>>> 0, cpu_to_be32(SPAPR_MEMORY_BLOCK_SIZE),
>>>>> cpu_to_be32(max_cpus / smp_threads),
>>>>> };
>>>>> + uint32_t maxdomains[] = {
>>>>> + cpu_to_be32(4),
>>>>> + cpu_to_be32(0),
>>>>> + cpu_to_be32(0),
>>>>> + cpu_to_be32(0),
>>>>> + cpu_to_be32(nb_numa_nodes - 1),
>>>>> + };
>>>>>
>>>>> _FDT(rtas = fdt_add_subnode(fdt, 0, "rtas"));
>>>>>
>>>>> @@ -946,6 +953,9 @@ static void spapr_dt_rtas(sPAPRMachineState *spapr,
>>>>> void *fdt)
>>>>> _FDT(fdt_setprop(fdt, rtas, "ibm,associativity-reference-points",
>>>>> refpoints, sizeof(refpoints)));
>>>>>
>>>>> + _FDT(fdt_setprop(fdt, rtas, "ibm,max-associativity-domains",
>>>>> + maxdomains, sizeof(maxdomains)));
>>>>> +
>>>>> _FDT(fdt_setprop_cell(fdt, rtas, "rtas-error-log-max",
>>>>> RTAS_ERROR_LOG_MAX));
>>>>> _FDT(fdt_setprop_cell(fdt, rtas, "rtas-event-scan-rate",
>>>>
>>>> This commit causes hash guest with latest guest kernel to hang at early
>>>> boot.
>>>
>>> I use v4.16 tag from stable and can't reproduce on P8 machine reported
>>> issue.
>>>
>>> Could you please share more details about your setup, kernel commit id
>>> you spot problem?
>>
>> I am on 4.16.0-rc7 (commit id: 0b412605ef5f)
>>
>> BTW this happens only for non-NUMA guest.
>
> Ah, that might explain it. With no NUMA nodes specified, I think this
> code will put a -1 into the max-associativity-domains property, which
> is probably causing the mess. If we don't have NUMA (nb_numa_nodes ==
> 0) we probably want to either omit the property entirely, or clamp
> that 5th cell to 0.
>
Ok, proposed fix already posted to qemu-devel. Sorry forgot to CC.
Mail subject contains (w/o quotas):
"spapr: Correct max associativity domains value for non-NUMA configs"
Tested with v4.16 tag:
o Before : non-NUMA configs: able to reproduce, stall during boot
o After : non-NUMA configs: not reproducible, boot is ok
--
Thanks,
Serhii
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- [Qemu-ppc] [PATCH for 2.13 v3 0/2] target/ppc: Support adding memory to initially memory-less NUMA nodes, Serhii Popovych, 2018/04/11
- [Qemu-ppc] [PATCH for 2.13 v3 1/2] spapr: Add ibm, max-associativity-domains property, Serhii Popovych, 2018/04/11
- Re: [Qemu-ppc] [PATCH for 2.13 v3 1/2] spapr: Add ibm, max-associativity-domains property, Bharata B Rao, 2018/04/13
- Re: [Qemu-ppc] [Qemu-devel] [PATCH for 2.13 v3 1/2] spapr: Add ibm, max-associativity-domains property, Serhii Popovych, 2018/04/16
- Re: [Qemu-ppc] [Qemu-devel] [PATCH for 2.13 v3 1/2] spapr: Add ibm, max-associativity-domains property, Bharata B Rao, 2018/04/16
- Re: [Qemu-ppc] [Qemu-devel] [PATCH for 2.13 v3 1/2] spapr: Add ibm, max-associativity-domains property, David Gibson, 2018/04/17
- Re: [Qemu-ppc] [Qemu-devel] [PATCH for 2.13 v3 1/2] spapr: Add ibm, max-associativity-domains property,
Serhii Popovych <=
[Qemu-ppc] [PATCH for 2.13 v3 2/2] Revert "spapr: Don't allow memory hotplug to memory less nodes", Serhii Popovych, 2018/04/11
Re: [Qemu-ppc] [PATCH for 2.13 v3 0/2] target/ppc: Support adding memory to initially memory-less NUMA nodes, David Gibson, 2018/04/11