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Message-ID: <32a53a8f-f6f8-6efc-a5f6-a004ffab8c99@bytedance.com>
Date:   Fri, 30 Sep 2022 16:43:07 +0800
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Subject: Re: [PATCH v3 1/2] mm: use update_mmu_tlb() on the second thread
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To:     David Hildenbrand <david@redhat.com>, akpm@linux-foundation.org,
        maobibo@loongson.cn, chenhuacai@loongson.cn,
        songmuchun@bytedance.com
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        loongarch@lists.linux.dev, chris@zankel.net, jcmvbkbc@gmail.com
References: <20220929112318.32393-1-zhengqi.arch@bytedance.com>
 <20220929112318.32393-2-zhengqi.arch@bytedance.com>
 <0fecbcdc-7324-2d76-8452-b60b4638d074@redhat.com>
From:   Qi Zheng <zhengqi.arch@bytedance.com>
In-Reply-To: <0fecbcdc-7324-2d76-8452-b60b4638d074@redhat.com>
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On 2022/9/30 16:30, David Hildenbrand wrote:
> On 29.09.22 13:23, Qi Zheng wrote:
>> As message in commit 7df676974359 ("mm/memory.c: Update local TLB
>> if PTE entry exists") said, we should update local TLB only on the
>> second thread. So in the do_anonymous_page() here, we should use
>> update_mmu_tlb() instead of update_mmu_cache() on the second thread.
>>
> 
> Maybe mention here "This only affects performance, but not correctness."

Oh, this is better. Hi Andrew, do I need to resend the v4?

> 
> Acked-by: David Hildenbrand <david@redhat.com>

Thanks.

> 
>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>> Reviewed-by: Muchun Song <songmuchun@bytedance.com>
>> ---
>>   mm/memory.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/memory.c b/mm/memory.c
>> index 118e5f023597..9e11c783ba0e 100644
>> --- a/mm/memory.c
>> +++ b/mm/memory.c
>> @@ -4122,7 +4122,7 @@ static vm_fault_t do_anonymous_page(struct 
>> vm_fault *vmf)
>>       vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address,
>>               &vmf->ptl);
>>       if (!pte_none(*vmf->pte)) {
>> -        update_mmu_cache(vma, vmf->address, vmf->pte);
>> +        update_mmu_tlb(vma, vmf->address, vmf->pte);
>>           goto release;
>>       }
> 

-- 
Thanks,
Qi