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

From: Kefeng Wang
Date: Tue Sep 28 2021 - 03:49:16 EST

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.

- add ACK/RB
- address comments about patch1 from Catalin
- add Greg and Andrew into list suggested by Catalin

- 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

- 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(-)