On 24 Jul 2024, at 20:35, Zi Yan wrote:

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

quoted

On 23 Jul 2024, at 2:41, Mike Rapoport wrote:

quoted

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

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@huawei.com/ (local)

v1: https://lore.kernel.org/all/20240716111346.3676969-1-rppt@kernel.org (local)
* 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.

OK, the issue comes from that my arm64 VM has no ACPI but x86_64 VM has it,
thus on arm64 VM numa_init(arch_acpi_numa_ini) failed in arch_numa_init()
and the code falls back to numa_init(dummy_numa_init). In dummy_numa_init(),
before patch 23 "arch_numa: switch over to numa_memblks", numa_add_memblk()
from drivers/base/arch_numa.c is called on arm64, which unconditionally
set 0 to numa_nodes_parsed. This is missing in the x86 version of
numa_add_memblk(), which is now used by all arch. By adding the patch
below, my arm64 kernel boots in the VM.

diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c
index 806550239d08..354f15b8d9b7 100644
--- a/drivers/base/arch_numa.c
+++ b/drivers/base/arch_numa.c

@@ -279,6 +279,7 @@ static int __init dummy_numa_init(void)
                pr_err("NUMA init failed\n");
                return ret;
        }
+       node_set(0, numa_nodes_parsed);

        numa_off = true;
        return 0;

Feel free to add

Tested-by: Zi Yan <ziy@nvidia.com> # for x86_64 and arm64

after you incorporate the fix.


--
Best Regards,
Yan, Zi