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Message-ID: <a2373558-920a-49b1-91ac-9b0a6a1468b2@vivo.com>
Date:   Thu, 19 Oct 2023 10:17:43 +0800
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH 2/2] mm: multi-gen lru: fix stat count
To:     Yu Zhao <yuzhao@google.com>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Suren Baghdasaryan <surenb@google.com>,
        Vlastimil Babka <vbabka@suse.cz>, linux-kernel@vger.kernel.org,
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        bpf@vger.kernel.org, opensource.kernel@vivo.com
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From:   Huan Yang <link@vivo.com>
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Hi Yu Zhao,

Thanks for your reply.

在 2023/10/19 0:21, Yu Zhao 写道:
> On Wed, Oct 18, 2023 at 2:22 AM Huan Yang <link@vivo.com> wrote:
>> For multi-gen lru reclaim in evict_folios, like shrink_inactive_list,
>> gather folios which isolate to reclaim, and invoke shirnk_folio_list.
>>
>> But, when complete shrink, it not gather shrink reclaim stat into sc,
>> we can't get info like nr_dirty\congested in reclaim, and then
>> control writeback, dirty number and mark as LRUVEC_CONGESTED, or
>> just bpf trace shrink and get correct sc stat.
>>
>> This patch fix this by simple copy code from shrink_inactive_list when
>> end of shrink list.
> MGLRU doesn't try to write back dirt file pages in the reclaim path --
> it filters them out in sort_folio() and leaves them to the page
Nice to know this,  sort_folio() filters some folio indeed.
But, I want to know, if we touch some folio in shrink_folio_list(), may some
folio become dirty or writeback even if sort_folio() filter then?
> writeback. (The page writeback is a dedicated component for this
> purpose). So there is nothing to fix.