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Date:   Thu, 21 Apr 2022 14:27:07 +0800
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Subject: Re: [PATCH -next v4 1/4] mm: page_table_check: move
 pxx_user_accessible_page into x86
To:     Anshuman Khandual <anshuman.khandual@arm.com>,
        Pasha Tatashin <pasha.tatashin@soleen.com>
CC:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Catalin Marinas" <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        "Paul Walmsley" <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-mm <linux-mm@kvack.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        <linux-riscv@lists.infradead.org>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Guohanjun <guohanjun@huawei.com>
References: <20220418034444.520928-1-tongtiangen@huawei.com>
 <20220418034444.520928-2-tongtiangen@huawei.com>
 <1671baf7-046e-7c52-183f-fd654125fd67@arm.com>
 <c376877e-53a7-d471-61bc-e7f9dd400d60@huawei.com>
 <CA+CK2bCF=7mADB=rxyHtVEd3oCZ4mxtKf=28L49uQr5oxUwYZQ@mail.gmail.com>
 <eec38afc-4ecc-29f8-9d8a-722661c30314@huawei.com>
 <75f444a6-4f50-4356-9e71-f72c59bf0a52@arm.com>
From:   Tong Tiangen <tongtiangen@huawei.com>
In-Reply-To: <75f444a6-4f50-4356-9e71-f72c59bf0a52@arm.com>
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在 2022/4/21 11:44, Anshuman Khandual 写道:
> 
> 
> On 4/21/22 08:35, Tong Tiangen wrote:
>>
>>
>> 在 2022/4/21 0:44, Pasha Tatashin 写道:
>>> On Wed, Apr 20, 2022 at 2:45 AM Tong Tiangen <tongtiangen@huawei.com> wrote:
>>>>
>>>>
>>>>
>>>> 在 2022/4/19 17:29, Anshuman Khandual 写道:
>>>>>
>>>>>
>>>>> On 4/18/22 09:14, Tong Tiangen wrote:
>>>>>> --- a/mm/page_table_check.c
>>>>>> +++ b/mm/page_table_check.c
>>>>>> @@ -10,6 +10,14 @@
>>>>>>     #undef pr_fmt
>>>>>>     #define pr_fmt(fmt)        "page_table_check: " fmt
>>>>>>
>>>>>> +#ifndef PMD_PAGE_SIZE
>>>>>> +#define PMD_PAGE_SIZE       PMD_SIZE
>>>>>> +#endif
>>>>>> +
>>>>>> +#ifndef PUD_PAGE_SIZE
>>>>>> +#define PUD_PAGE_SIZE       PUD_SIZE
>>>>>> +#endif
>>>>>
>>>>> Why cannot PMD_SIZE/PUD_SIZE be used on every platform instead ? What is the
>>>>> need for using PUD_PAGE_SIZE/PMD_PAGE_SIZE ? Are they different on x86 ?
>>>>> .
>>>>
>>>> Hi, Pasha：
>>>> I checked the definitions of PMD_SIZE/PUD_SIZE and
>>>> PUD_PAGE_SIZE/PMD_PAGE_SIZE in x86 architecture and their use outside
>>>> the architecture(eg: in mm/, all used PMD_SIZE/PUD_SIZE), Would it be
>>>> better to use a unified PMD_SIZE/PUD_SIZE here?
>>>
>>> Hi Tong,
>>>
>>> Yes, it makes sense to use PMD_SIZE/PUD_SIZE instead of
>>> PUD_PAGE_SIZE/PMD_PAGE_SIZE in page_table_check to be inline with the
>>> rest of the mm/
>>>
>>> Pasha
>>>
>> Hi Pasha and Anshuman:
>>
>> OK, Functional correctness is not affected here, i plan to optimize this point after this patchset is merged.
> 
> As page table check is now being proposed to be supported on multiple platforms i.e
> arm64, riscv besides just x86, it should not have any architecture specific macros
> or functions. Hence please do generalize these PMD/PUD sizes in this series itself.
> .

OK, will resend.

Thank you.
Tong.