linux-kernel - Re: sched: CPU #1's llc-sibling CPU #0 is not on the same node!

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Date:	Tue, 26 Feb 2013 13:36:30 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Don Morris <don.morris@...com>, "H. Peter Anvin" <hpa@...or.com>,
	Tejun Heo <tj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Tony Luck <tony.luck@...el.com>,
	Thomas Renninger <trenn@...e.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Tim Gardner <tim.gardner@...onical.com>,
	linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
	x86@...nel.org, a.p.zijlstra@...llo.nl, jarkko.sakkinen@...el.com,
	tangchen@...fujitsu.com
Subject: Re: sched: CPU #1's llc-sibling CPU #0 is not on the same node!

On Mon, Feb 25, 2013 at 2:50 PM, Yinghai Lu <yinghai@...nel.org> wrote:
> On Mon, Feb 25, 2013 at 1:27 PM, Don Morris <don.morris@...com> wrote:
>> On 02/25/2013 10:32 AM, Tim Gardner wrote:
>>> On 02/25/2013 08:02 AM, Tim Gardner wrote:
>>>> Is this an expected warning ? I'll boot a vanilla kernel just to be sure.
>>>>
>>>> rebased against ab7826595e9ec51a51f622c5fc91e2f59440481a in Linus' repo:
>>>>
>>>
>>> Same with a vanilla kernel, so it doesn't appear that any Ubuntu cruft
>>> is having an impact:
>>
>> Reproduced on a HP z620 workstation (E5-2620 instead of E5-2680, but
>> still Sandy Bridge, though I don't think that matters).
>>
>> Bisection leads to:
>> # bad: [e8d1955258091e4c92d5a975ebd7fd8a98f5d30f] acpi, memory-hotplug:
>> parse SRAT before memblock is ready
>>
>> Nothing terribly obvious leaps out as to *why* that reshuffling messes
>> up the cpu<-->node bindings, but I wanted to put this out there while
>> I poke around further. [Note that the SRAT: PXM -> APIC -> Node print
>> outs during boot are the same either way -- if you look at the APIC
>> numbers of the processors (from /proc/cpuinfo), the processors should
>> be assigned to the correct node, but they aren't.] cc'ing Tang Chen
>> in case this is obvious to him or he's already fixed it somewhere not
>> on Linus's tree yet.
>>
>> Don Morris
>>
>>>
>>> [    0.170435] ------------[ cut here ]------------
>>> [    0.170450] WARNING: at arch/x86/kernel/smpboot.c:324
>>> topology_sane.isra.2+0x71/0x84()
>>> [    0.170452] Hardware name: S2600CP
>>> [    0.170454] sched: CPU #1's llc-sibling CPU #0 is not on the same
>>> node! [node: 1 != 0]. Ignoring dependency.
>>> [    0.156000] smpboot: Booting Node   1, Processors  #1
>>> [    0.170455] Modules linked in:
>>> [    0.170460] Pid: 0, comm: swapper/1 Not tainted 3.8.0+ #1
>>> [    0.170461] Call Trace:
>>> [    0.170466]  [<ffffffff810597bf>] warn_slowpath_common+0x7f/0xc0
>>> [    0.170473]  [<ffffffff810598b6>] warn_slowpath_fmt+0x46/0x50
>>> [    0.170477]  [<ffffffff816cc752>] topology_sane.isra.2+0x71/0x84
>>> [    0.170482]  [<ffffffff816cc9de>] set_cpu_sibling_map+0x23f/0x436
>>> [    0.170487]  [<ffffffff816ccd0c>] start_secondary+0x137/0x201
>>> [    0.170502] ---[ end trace 09222f596307ca1d ]---
>
> that commit is totally broken, and it should be reverted.
>
> 1. numa_init is called several times, NOT just for srat. so those
>    nodes_clear(numa_nodes_parsed)
>    memset(&numa_meminfo, 0, sizeof(numa_meminfo))
> can not be just removed.
> please consider sequence is: numaq, srat, amd, dummy.
> You need to make fall back path working!
>
> 2. simply split acpi_numa_init to early_parse_srat.
> a. that early_parse_srat is NOT called for ia64, so you break ia64.
> b.  for (i = 0; i < MAX_LOCAL_APIC; i++)
>      set_apicid_to_node(i, NUMA_NO_NODE)
> still left in numa_init. So it will just clear result from early_parse_srat.
> it should be moved before that....

   c.  it breaks ACPI_TABLE_OVERIDE...as the acpi table scan is moved
early before override from INITRD is settled.

>
> 3. that patch TITLE is total misleading, there is NO x86 in the title,
> but it changes
> to x86 code.
>
> 4, it does not CC to TJ and other numa guys...
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