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. 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 > > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
