Re: [PATCH v2 0/4] Revert works for the mapping of cpuid <-> nodeid

Ye Xiaolong
2017-02-21T07:12:13Z

On 02/21, Ye Xiaolong wrote:
>On 02/20, Dou Liyang wrote:
>>Currently, We make the mapping of "cpuid <-> nodeid" fixed at the booting time.
>>It keeps consistent with the WorkQueue and avoids some bugs which may be caused
>>by the dynamic assignment.
>>As we know, It is implemented by the patches as follows: 2532fc318d, f7c28833c2,
>>8f54969dc8, 8ad893faf2, dc6db24d24, which depend on ACPI table. Simply speaking:
>>
>>Step 1. Make the "Logical CPU ID <-> Processor ID/UID" fixed Using MADT:
>>We generate the logical CPU IDs by the Local APIC/x2APIC IDs orderly and
>>get the mapping of Processor ID/UID <-> Local Apic ID directly in MADT.
>>So, we get the mapping of
>>*Processor ID/UID <-> Local Apic ID <-> Logical CPU ID*
>>
>>Step 2. Make the "Processor ID/UID <-> Node ID(_PXM)" fixed Using DSDT:
>>The maaping of "Processor ID/UID <-> Node ID(_PXM)" is ready-made in
>>each entities. we just use it directly.
>>
>>So, at last we get the maaping of *Node ID <-> Logical CPU ID* according to
>>step1 and step2:
>>*Node ID(_PXM) <-> Processor ID/UID <-> Local Apic ID <-> Logical CPU ID*
>>
>>But, The ACPI table is unreliable and it is very risky that we use the entity
>>which isn't related to a physical device at booting time. Here has already two
>>bugs we found.
>>1. Duplicated Processor IDs in DSDT.
>> It has been fixed by commit 8e089eaa19, fd74da217d.
>>2. The _PXM in DSDT is inconsistent with the one in MADT.
>> It may cause the bug, which is shown in:
>> https://lkml.org/lkml/2017/2/12/200
>>There may be more later. We shouldn't just only fix them everytime, we should
>>solve this problem from the source to avoid such problems happend again and
>>again.
>>
>>Now, a simple and easy way is found, we revert our patches. Do the Step 2
>>at hot-plug time, not at booting time where we did some useless work.
>>
>>It also can make the mapping of "cpuid <-> nodeid" fixed and avoid excessive
>>use of the ACPI table.
>>
>>We have tested them in our box: Fujitsu PQ2000 with 2 nodes for hot-plug.
>>To Xiaolong:
>> Please help me to test it in the special machine.
>
>Got it, I'll queue the tests on the previous machine and let you know the result
>once I get it.

Previous kernel panic and incomplete run issue (described in [1]) in 0day
system is gone with this series.

Tested-by: Xiaolong Ye <xiaolong.ye@intel.com>

Here is the comparison:

$ compare -at dc6db24d2476cd09c0ecf2b8d80313539f737a89 2e61bac54fad4c018afd23c118bce2399e504020
tests: 1
testcase/path_params/tbox_group/run: vm-scalability/300-never-never-1-1-swap-w-rand-performance/lkp-hsw-ep2

Here dc6db24d24 is previous first bad commit, 2e61bac54 is the head commit of your series
applied on top of latest tip of linus/master c945d0227d ("Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")

dc6db24d2476cd09 2e61bac54fad4c018afd23c118
---------------- --------------------------
fail:runs %reproduction fail:runs
| | |
:12 12% 1:8 last_state.OOM
:12 12% 1:8 dmesg.page_allocation_failure:order:#,mode:#(GFP_USER|GFP_DMA32|__GFP_ZERO)
:12 12% 1:8 dmesg.Mem-Info
12:12 -100% :8 dmesg.BUG:unable_to_handle_kernel
12:12 -100% :8 dmesg.Oops
12:12 -100% :8 dmesg.RIP:get_partial_node
9:12 -75% :8 dmesg.RIP:_raw_spin_lock_irqsave
3:12 -25% :8 dmesg.general_protection_fault:#[##]SMP
3:12 -25% :8 dmesg.RIP:native_queued_spin_lock_slowpath
3:12 -25% :8 dmesg.Kernel_panic-not_syncing:Hard_LOCKUP
2:12 -17% :8 dmesg.RIP:load_balance
2:12 -17% :8 dmesg.Kernel_panic-not_syncing:Fatal_exception_in_interrupt
1:12 -8% :8 dmesg.RIP:resched_curr
1:12 -8% :8 dmesg.Kernel_panic-not_syncing:Fatal_exception
5:12 -42% :8 dmesg.WARNING:at_include/linux/uaccess.h:#__probe_kernel_read
1:12 -8% :8 dmesg.WARNING:at_lib/list_debug.c:#__list_add

[1] https://lkml.org/lkml/2017/2/12/200

Thanks,
Xiaolong

>
>Thanks,
>Xiaolong
>>
>>Change log:
>> v1 -> v2: 1. fix some comments.
>> 2. add the verification of duplicate processor id.
>>
>>Dou Liyang (4):
>> Revert"x86/acpi: Set persistent cpuid <-> nodeid mapping when booting"
>> Revert"x86/acpi: Enable MADT APIs to return disabled apicids"
>> acpi: Fix the check handle in case of declaring processors using the
>> Device operator
>> acpi: Move the verification of duplicate proc_id from booting time to
>> hot-plug time
>>
>> arch/x86/kernel/acpi/boot.c | 2 +-
>> drivers/acpi/acpi_processor.c | 50 +++++++++++-----
>> drivers/acpi/bus.c | 1 -
>> drivers/acpi/processor_core.c | 133 +++++++-----------------------------------
>> include/linux/acpi.h | 5 +-
>> 5 files changed, 59 insertions(+), 132 deletions(-)
>>
>>--
>>2.5.5
>>
>>
>>