linux-kernel - Re: [PATCH v3] mm/damon: Add access checking for hugetlb pages

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Message-ID: <bc873789-e025-8366-88a8-f3dadcdd9db9@linux.alibaba.com>
Date:   Tue, 4 Jan 2022 10:36:00 +0800
From:   Baolin Wang <baolin.wang@...ux.alibaba.com>
To:     SeongJae Park <sj@...nel.org>
Cc:     akpm@...ux-foundation.org, mike.kravetz@...cle.com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] mm/damon: Add access checking for hugetlb pages

Hi SeongJae,

On 12/31/2021 2:19 AM, SeongJae Park wrote:
> On Thu, 30 Dec 2021 16:20:28 +0800 Baolin Wang <baolin.wang@...ux.alibaba.com> wrote:
> 
>> The process's VMAs can be mapped by hugetlb page, but now the DAMON
>> did not implement the access checking for hugetlb pte, so we can not
>> get the actual access count like below if a process VMAs were mapped
>> by hugetlb.
>>
>> damon_aggregated: target_id=18446614368406014464 nr_regions=12 4194304-5476352: 0 545
>> damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662370467840-140662372970496: 0 545
>> damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662372970496-140662375460864: 0 545
>> damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662375460864-140662377951232: 0 545
>> damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662377951232-140662380449792: 0 545
>> damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662380449792-140662382944256: 0 545
>> ......
>>
>> Thus this patch adds hugetlb access checking support, with this patch
>> we can see below VMA mapped by hugetlb access count.
>>
>> damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296486649856-140296489914368: 1 3
>> damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296489914368-140296492978176: 1 3
>> damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296492978176-140296495439872: 1 3
>> damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296495439872-140296498311168: 1 3
>> damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296498311168-140296501198848: 1 3
>> damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296501198848-140296504320000: 1 3
>> damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296504320000-140296507568128: 1 2
>> ......
>>
>> Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
> 
> In addition to unwrapping program outputs in commit message, I personally
> prefer indenting those with 4 spaces[1], but I wouldn't bother you for such a
> trivial thing.  Thank you for this patch!

I noticed your comments before, but I still think the message line is 
too long to unreadable. Anyway thanks for your reviewing.

> 
> Reviewed-by: SeongJae Park <sj@...nel.org>
> 
> [1] https://lore.kernel.org/linux-mm/17421c73-2124-63c2-1925-dcea5c976711@linux.alibaba.co