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Subject: Re: [PATCH v2 0/3] arm64: support page mapping percpu first chunk
 allocator
To:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>
CC:     <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <kasan-dev@googlegroups.com>,
        <linux-mm@kvack.org>
References: <20210720025105.103680-1-wangkefeng.wang@huawei.com>
From:   Kefeng Wang <wangkefeng.wang@huawei.com>
Message-ID: <2c1254a7-561c-9b99-444b-c2d9aefa7b55@huawei.com>
Date:   Mon, 26 Jul 2021 09:19:11 +0800
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Hi Will and Catalin，any comments，kindly ping, thanks.

On 2021/7/20 10:51, 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-rc2.
>
> V2:
> - fix build error when CONFIG_KASAN disabled, found by lkp@intel.com
> - drop wrong __weak comment from kasan_populate_early_vm_area_shadow(),
>    found by Marco Elver <elver@google.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 | 17 ++++++++
>   drivers/base/arch_numa.c   | 82 +++++++++++++++++++++++++++++++++-----
>   include/linux/kasan.h      |  6 +++
>   mm/kasan/init.c            |  5 +++
>   mm/vmalloc.c               |  9 +++--
>   6 files changed, 110 insertions(+), 13 deletions(-)
>