linux-kernel - Re: [PATCH v3 0/3] arm64: support page mapping percpu first chunk allocator

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Message-ID: <9b75f4e5-a675-1227-0476-43fc21509086@huawei.com>
Date:   Thu, 12 Aug 2021 14:07:36 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     <will@...nel.org>, <catalin.marinas@....com>,
        <ryabinin.a.a@...il.com>, <andreyknvl@...il.com>,
        <dvyukov@...gle.com>, <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
CC:     <kasan-dev@...glegroups.com>, <linux-mm@...ck.org>,
        <elver@...gle.com>
Subject: Re: [PATCH v3 0/3] arm64: support page mapping percpu first chunk
 allocator

Hi Catalin and Will，

The drivers/base/arch_numa.c is only shared by riscv and arm64,

and the change from patch2 won't broke riscv.

Could all patches be merged by arm64 tree? or any new comments?

Many thanks.

On 2021/8/9 17:37, 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-rc5.
>
> 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@...gle.com> to patch v3
>
> V2:
> - fix build error when CONFIG_KASAN disabled, found by lkp@...el.com
> - drop wrong __weak comment from kasan_populate_early_vm_area_shadow(),
>    found by Marco Elver <elver@...gle.com>
>
> 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               | 17 +++++---
>   6 files changed, 115 insertions(+), 15 deletions(-)
>