linux-kernel - Re: [PATCH] mm: fix misuse of update_mmu_cache() in do_anonymous

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Message-ID: <babdbd1f-9629-c23a-f29f-7520ced3854b@bytedance.com>
Date:   Mon, 26 Sep 2022 16:47:28 +0800
From:   Qi Zheng <zhengqi.arch@...edance.com>
To:     David Hildenbrand <david@...hat.com>,
        Muchun Song <muchun.song@...ux.dev>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Linux MM <linux-mm@...ck.org>, linux-kernel@...r.kernel.org,
        chris@...kel.net, jcmvbkbc@...il.com, maobibo@...ngson.cn
Subject: Re: [PATCH] mm: fix misuse of update_mmu_cache() in
 do_anonymous_page()



On 2022/9/26 16:42, David Hildenbrand wrote:
> On 26.09.22 10:41, Qi Zheng wrote:
>>
>>
>> On 2022/9/26 16:32, David Hildenbrand wrote:
>>> On 25.09.22 03:43, Muchun Song wrote:
>>>>
>>>>
>>>>> On Sep 24, 2022, at 13:32, Qi Zheng <zhengqi.arch@...edance.com> 
>>>>> 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 fix the misuse of update_mmu_cache() by using
>>>>> update_mmu_tlb() in the do_anonymous_page().
>>>>>
>>>>> Signed-off-by: Qi Zheng <zhengqi.arch@...edance.com>
>>>>
>>>> The change looks good to me. However, I am not sure what is the
>>>> user-visible
>>>> effect to xtensa users. So Cc xtensa’s maintainer and the author of
>>>> 7df676974359
>>>> to double check this.
>>>
>>> And if there is one, do we have a fixes tag?
>>
>> IIUC, there's only a performance difference here, so maybe there's no
>> need to add the fixes tag?
> 
> Maybe be careful with the usage of "fix" in subject/description then and 
> point that out in the description :)

Ah, will change subject/description in the v2, thanks. :)

> 

-- 
Thanks,
Qi