Re: [PATCH v4 0/3] arm64: support page mapping percpu first chunk allocator

[Kefeng Wang]

Hi Catalin and Andrew, kindly ping again, any comments, thanks.

On 2021/9/10 13:33, Kefeng Wang wrote:
> Percpu embedded first chunk allocator is the firstly option, but it
> could fails on ARM64, eg,
>    "percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 0x781fefff0000"
>    "percpu: max_distance=0x600000540000 too large for vmalloc space 0x7dffb7ff0000"
>    "percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 0x5dffb7ff0000"
>
> then we could meet "WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 pcpu_get_vm_areas+0x488/0x838",
> even the system could not boot successfully.
>
> Let's implement page mapping percpu first chunk allocator as a fallback
> to the embedding allocator to increase the robustness of the system.
>
> Also fix a crash when both NEED_PER_CPU_PAGE_FIRST_CHUNK and KASAN_VMALLOC enabled.
>
> Tested on ARM64 qemu with cmdline "percpu_alloc=page" based on v5.14.
>
> V4:
> - add ACK/RB
> - address comments about patch1 from Catalin
> - add Greg and Andrew into list suggested by Catalin
>
> v3:
> - search for a range that fits instead of always picking the end from
>    vmalloc area suggested by Catalin.
> - use NUMA_NO_NODE to avoid "virt_to_phys used for non-linear address:"
>    issue in arm64 kasan_populate_early_vm_area_shadow().
> - add Acked-by: Marco Elver <elver@xxxxxxxxxx> to patch v3
>
> V2:
> - fix build error when CONFIG_KASAN disabled, found by lkp@xxxxxxxxx
> - drop wrong __weak comment from kasan_populate_early_vm_area_shadow(),
>    found by Marco Elver <elver@xxxxxxxxxx>
>
> Kefeng Wang (3):
>    vmalloc: Choose a better start address in vm_area_register_early()
>    arm64: Support page mapping percpu first chunk allocator
>    kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC
>
>   arch/arm64/Kconfig         |  4 ++
>   arch/arm64/mm/kasan_init.c | 16 ++++++++
>   drivers/base/arch_numa.c   | 82 +++++++++++++++++++++++++++++++++-----
>   include/linux/kasan.h      |  6 +++
>   mm/kasan/init.c            |  5 +++
>   mm/vmalloc.c               | 19 ++++++---
>   6 files changed, 116 insertions(+), 16 deletions(-)