Re: [PATCH v2 00/25] mm: introduce numa_memblks

[Zi Yan]

On 24 Jul 2024, at 18:44, Zi Yan wrote:

> On 23 Jul 2024, at 2:41, Mike Rapoport wrote:
>
>> From: "Mike Rapoport (Microsoft)" <rppt@xxxxxxxxxx>
>>
>> Hi,
>>
>> Following the discussion about handling of CXL fixed memory windows on
>> arm64 [1] I decided to bite the bullet and move numa_memblks from x86 to
>> the generic code so they will be available on arm64/riscv and maybe on
>> loongarch sometime later.
>>
>> While it could be possible to use memblock to describe CXL memory windows,
>> it currently lacks notion of unpopulated memory ranges and numa_memblks
>> does implement this.
>>
>> Another reason to make numa_memblks generic is that both arch_numa (arm64
>> and riscv) and loongarch use trimmed copy of x86 code although there is no
>> fundamental reason why the same code cannot be used on all these platforms.
>> Having numa_memblks in mm/ will make it's interaction with ACPI and FDT
>> more consistent and I believe will reduce maintenance burden.
>>
>> And with generic numa_memblks it is (almost) straightforward to enable NUMA
>> emulation on arm64 and riscv.
>>
>> The first 9 commits in this series are cleanups that are not strictly
>> related to numa_memblks.
>> Commits 10-16 slightly reorder code in x86 to allow extracting numa_memblks
>> and NUMA emulation to the generic code.
>> Commits 17-19 actually move the code from arch/x86/ to mm/ and commits 20-22
>> does some aftermath cleanups.
>> Commit 23 switches arch_numa to numa_memblks.
>> Commit 24 enables usage of phys_to_target_node() and
>> memory_add_physaddr_to_nid() with numa_memblks.
>> Commit 25 moves the description for numa=fake from x86 to admin-guide
>>
>> [1] https://lore.kernel.org/all/20240529171236.32002-1-Jonathan.Cameron@xxxxxxxxxx/
>>
>> v1: https://lore.kernel.org/all/20240716111346.3676969-1-rppt@xxxxxxxxxx
>> * add cleanup for arch_alloc_nodedata and HAVE_ARCH_NODEDATA_EXTENSION
>> * add patch that moves description of numa=fake kernel parameter from
>>   x86 to admin-guide
>> * reduce rounding up of node_data allocations from PAGE_SIZE to
>>   SMP_CACHE_BYTES
>> * restore single allocation attempt of numa_distance
>> * fix several comments
>> * added review tags
>>
>> Mike Rapoport (Microsoft) (25):
>>   mm: move kernel/numa.c to mm/
>>   MIPS: sgi-ip27: make NODE_DATA() the same as on all other architectures
>>   MIPS: sgi-ip27: ensure node_possible_map only contains valid nodes
>>   MIPS: sgi-ip27: drop HAVE_ARCH_NODEDATA_EXTENSION
>>   MIPS: loongson64: rename __node_data to node_data
>>   MIPS: loongson64: drop HAVE_ARCH_NODEDATA_EXTENSION
>>   mm: drop CONFIG_HAVE_ARCH_NODEDATA_EXTENSION
>>   arch, mm: move definition of node_data to generic code
>>   arch, mm: pull out allocation of NODE_DATA to generic code
>>   x86/numa: simplify numa_distance allocation
>>   x86/numa: use get_pfn_range_for_nid to verify that node spans memory
>>   x86/numa: move FAKE_NODE_* defines to numa_emu
>>   x86/numa_emu: simplify allocation of phys_dist
>>   x86/numa_emu: split __apicid_to_node update to a helper function
>>   x86/numa_emu: use a helper function to get MAX_DMA32_PFN
>>   x86/numa: numa_{add,remove}_cpu: make cpu parameter unsigned
>>   mm: introduce numa_memblks
>>   mm: move numa_distance and related code from x86 to numa_memblks
>>   mm: introduce numa_emulation
>>   mm: numa_memblks: introduce numa_memblks_init
>>   mm: numa_memblks: make several functions and variables static
>>   mm: numa_memblks: use memblock_{start,end}_of_DRAM() when sanitizing
>>     meminfo
>>   arch_numa: switch over to numa_memblks
>>   mm: make range-to-target_node lookup facility a part of numa_memblks
>>   docs: move numa=fake description to kernel-parameters.txt
>>
> Hi,
>
> I have tested this series on both x86_64 and arm64. It works fine on x86_64.
> All numa=fake= options work as they did before the series.
>
> But I am not able to boot the kernel (no printout at all) on arm64 VM
> (Mac mini M1 VMWare). By git bisecting, arch_numa: switch over to numa_memblks
> is the first patch causing the boot failure. I see the warning:
>
> WARNING: modpost: vmlinux: section mismatch in reference: numa_add_cpu+0x1c (section: .text) -> early_cpu_to_node (section: .init.text)
>
> I am not sure if it is red herring or not, since changing early_cpu_to_node
> to cpu_to_node in numa_add_cpu() from mm/numa_emulation.c did get rid of the
> warning, but the system still failed to boot.
>
> Please note that you need binutils 2.40 to build the arm64 kernel, since there
> is a bug(https://sourceware.org/bugzilla/show_bug.cgi?id=31924) in 2.42 preventing
> arm64 kernel from booting as well.
>
> My config is attached.

I get more info after adding earlycon to the boot option.
pgdat is NULL, causing issues when free_area_init_node() is dereferencing
it at first WARN_ON.

FYI, my build is this series on top of v6.10 instead of the base commit,
where the series applies cleanly on top v6.10.

[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000080000000-0x00000000ffd82fff]
[    0.000000]   node   0: [mem 0x00000000ffd83000-0x00000000fffb5fff]
[    0.000000]   node   0: [mem 0x00000000fffb6000-0x000000017befffff]
[    0.000000]   node   0: [mem 0x000000017bf00000-0x000000017bfbffff]
[    0.000000]   node   0: [mem 0x000000017bfc0000-0x000000017c02ffff]
[    0.000000]   node   0: [mem 0x000000017c030000-0x000000017c03ffff]
[    0.000000]   node   0: [mem 0x000000017c040000-0x000000017c09ffff]
[    0.000000]   node   0: [mem 0x000000017c0a0000-0x000000017c13ffff]
[    0.000000]   node   0: [mem 0x000000017c140000-0x000000017f41ffff]
[    0.000000]   node   0: [mem 0x000000017f420000-0x000000017f4affff]
[    0.000000]   node   0: [mem 0x000000017f4b0000-0x000000017f5bffff]
[    0.000000]   node   0: [mem 0x000000017f5c0000-0x000000017f5dffff]
[    0.000000]   node   0: [mem 0x000000017f5e0000-0x000000017fffffff]
[    0.000000] pgdat: 0000000000000000, nid: 0
[    0.000000] Unable to handle kernel paging request at virtual address 0000000000002220
[    0.000000] Mem abort info:
[    0.000000]   ESR = 0x0000000096000004
[    0.000000]   EC = 0x25: DABT (current EL), IL = 32 bits
[    0.000000]   SET = 0, FnV = 0
[    0.000000]   EA = 0, S1PTW = 0
[    0.000000]   FSC = 0x04: level 0 translation fault
[    0.000000] Data abort info:
[    0.000000]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[    0.000000]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[    0.000000]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[    0.000000] [0000000000002220] user address but active_mm is swapper
[    0.000000] Internal error: Oops: 0000000096000004 [#1] SMP
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.10.0+ #17
[    0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[    0.000000] pc : free_area_init+0x720/0xf90
[    0.000000] lr : free_area_init+0x714/0xf90
[    0.000000] sp : ffff800081eb3c20
[    0.000000] x29: ffff800081eb3c20 x28: 000000017b5e710c x27: ffff800082158000
[    0.000000] x26: 000000017ffff168 x25: ffff800081ecc000 x24: 0000000000000000
[    0.000000] x23: 0000000000000000 x22: 0000000000000000 x21: ffff8000821f0480
[    0.000000] x20: 0000000000000000 x19: ffff8000818863f0 x18: 0000000000000006
[    0.000000] x17: 00000000007fb000 x16: 000000017f805000 x15: ffff800081eb36b0
[    0.000000] x14: 0000000000000000 x13: 30203a64696e202c x12: ffff800081f3ef10
[    0.000000] x11: 0000000000000001 x10: 0000000000000001 x9 : 0000000000017fe8
[    0.000000] x8 : c0000000ffffefff x7 : ffff800081ee6d40 x6 : 0000000000057fa8
[    0.000000] x5 : ffff800081f3eeb8 x4 : 0000000000000000 x3 : 0000000000000000
[    0.000000] x2 : 0000000000000000 x1 : ffff800081ec8c40 x0 : 000000000000001f
[    0.000000] Call trace:
[    0.000000]  free_area_init+0x720/0xf90
[    0.000000]  bootmem_init+0x158/0x218
[    0.000000]  setup_arch+0x220/0x650
[    0.000000]  start_kernel+0x74/0x7e0
[    0.000000]  __primary_switched+0x80/0x90
[    0.000000] Code: 97a64606 b940b7f6 a90dffff f876dab4 (b9622280)
[    0.000000] ---[ end trace 0000000000000000 ]---
[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

--
Best Regards,
Yan, Zi

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