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Date:   Mon, 12 Jun 2023 12:53:53 +0200
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Subject: Re: [PATCH v5 3/3] mm,page_owner: Filter out stacks by a threshold
 counter
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To:     Alexander Potapenko <glider@google.com>,
        Oscar Salvador <osalvador@suse.de>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Michal Hocko <mhocko@suse.com>,
        Waiman Long <longman@redhat.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Marco Elver <elver@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Eric Dumazet <edumazet@google.com>
References: <20230516182537.3139-1-osalvador@suse.de>
 <20230516182537.3139-4-osalvador@suse.de>
 <CAG_fn=UJgnLFGgpkXbMeD6axZN_ifEPHvWpy2_oiPyG1a6PXng@mail.gmail.com>
From:   Vlastimil Babka <vbabka@suse.cz>
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On 5/22/23 10:40, Alexander Potapenko wrote:
> On Tue, May 16, 2023 at 8:25 PM Oscar Salvador <osalvador@suse.de> wrote:
>> We want to be able to filter out the output on a threshold basis,
>> in this way we can get rid of a lot of noise and focus only on those
>> stacks which have an allegedly high counter.
>>
>> We can control the threshold value by a new file called
>> 'page_owner_threshold', which is 0 by default.
>>
>> Signed-off-by: Oscar Salvador <osalvador@suse.de>
> Nack.
> We must decouple stackdepot from page_owner as much as possible, not
> add extra dependencies by sharing variables between the two.
> 
> What you need here is a pair of xxx_iter_start()/xxx_iter_next()
> functions in stackdepot.c that will hold the iteration state in a
> struct and return the next stack trace.
> The threshold value can also be part of that struct.

Agreed, that should be a much cleaner approach.