linux-kernel - Re: [PATCH v6 2/2] arm64: support batched/deferred tlb shootdown during page reclamation

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Message-ID: <91e4804d-cb99-fd22-dafd-2f418f5c7ba9@huawei.com>
Date:   Wed, 16 Nov 2022 09:50:58 +0800
From:   Yicong Yang <yangyicong@...wei.com>
To:     Nadav Amit <namit@...are.com>
CC:     <yangyicong@...ilicon.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linux-MM <linux-mm@...ck.org>,
        "linux-arm-kernel@...ts.infradead.org" 
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        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
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        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        Jonathan Corbet <corbet@....net>,
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        kernel list <linux-kernel@...r.kernel.org>,
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        Mel Gorman <mgorman@...e.de>
Subject: Re: [PATCH v6 2/2] arm64: support batched/deferred tlb shootdown
 during page reclamation

On 2022/11/16 7:38, Nadav Amit wrote:
> On Nov 14, 2022, at 7:14 PM, Yicong Yang <yangyicong@...wei.com> wrote:
> 
>> diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
>> index 8a497d902c16..5bd78ae55cd4 100644
>> --- a/arch/x86/include/asm/tlbflush.h
>> +++ b/arch/x86/include/asm/tlbflush.h
>> @@ -264,7 +264,8 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm)
>> }
>>
>> static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch,
>> -					struct mm_struct *mm)
>> +					struct mm_struct *mm,
>> +					unsigned long uaddr)
> 
> Logic-wise it looks fine. I notice the “v6", and it should not be blocking,
> but I would note that the name "arch_tlbbatch_add_mm()” does not make much
> sense once the function also takes an address.
> 

ok the add_mm should still apply to x86 since the address is not used, but not for arm64.

> It could’ve been something like arch_set_tlb_ubc_flush_pending() but that’s
> too long. I’m not very good with naming, but the current name is not great.
> 

What about arch_tlbbatch_add_pending()? Considering the x86 is pending the flush operation
while arm64 is pending the sychronization operation, arch_tlbbatch_add_pending() should
make sense to both.

Thanks.