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Subject: Re: [PATCH v3 0/3] arm64: support page mapping percpu first chunk
 allocator
From:   Kefeng Wang <wangkefeng.wang@huawei.com>
To:     <will@kernel.org>, <catalin.marinas@arm.com>,
        <ryabinin.a.a@gmail.com>, <andreyknvl@gmail.com>,
        <dvyukov@google.com>, <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
CC:     <kasan-dev@googlegroups.com>, <linux-mm@kvack.org>,
        <elver@google.com>
References: <20210809093750.131091-1-wangkefeng.wang@huawei.com>
 <9b75f4e5-a675-1227-0476-43fc21509086@huawei.com>
Message-ID: <7904a638-3ee2-381f-6dfb-3d011df42c40@huawei.com>
Date:   Mon, 23 Aug 2021 10:29:32 +0800
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On 2021/8/12 14:07, Kefeng Wang wrote:
> 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?

Kindly ping...

>
> 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@google.com> to patch v3
>>
>> 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 | 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(-)
>>