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Date:   Mon, 5 Sep 2022 15:00:24 +0200
From:   Marco Elver <elver@google.com>
To:     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>,
        Vlastimil Babka <vbabka@suse.cz>,
        Eric Dumazet <edumazet@google.com>,
        Waiman Long <longman@redhat.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Alexander Potapenko <glider@google.com>
Subject: Re: [PATCH v2 2/3] mm, page_owner: Add page_owner_stacks file to
 print out only stacks and their counter
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References: <20220905031012.4450-1-osalvador@suse.de>
 <20220905031012.4450-3-osalvador@suse.de>
 <YxXyThZanSl3wboo@elver.google.com>
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On Mon, Sep 05, 2022 at 02:57PM +0200, Marco Elver wrote:
[...]
> > +{
> > +	int i = *pos, ret = 0;
> > +	struct stack_record **stacks, *stack;
> > +	static struct stack_record *last = NULL;
> > +	unsigned long stack_table_entries = stack_hash_mask + 1;
> > +
> > +	/* Continue from the last stack if we have one */
> > +	if (last) {
> > +		stack = last->next;
> 
> This is dead code?

Oof, I just noticed that 'last' is static. Please avoid that, because
it'll make this interface really tricky to use safely. I still don't
quite understand why it needs to do this, and a kernel-doc comment would
make this clearer.