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

From: Dou Liyang
Date: Tue Feb 21 2017 - 20:57:22 EST

Hi, Xiaolong

At 02/21/2017 03:10 PM, Ye Xiaolong wrote:
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:
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

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.

Thanks very much, I am glad to hear that!

Tested-by: Xiaolong Ye <>

I will add it in my next version.


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://")

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




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(-)