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Date:   Sat, 4 Jul 2020 12:39:44 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Alex Shi <alex.shi@linux.alibaba.com>
Cc:     Konstantin Khlebnikov <koct9i@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
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Subject: Re: [PATCH v14 15/20] mm/swap: serialize memcg changes during
 pagevec_lru_move_fn
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On Sat, Jul 04, 2020 at 07:34:59PM +0800, Alex Shi wrote:
> That's a great idea! Guess what the new struct we need would be like this?
> I like to try this. :)
> 
> 
> diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
> index 081d934eda64..d62778c8c184 100644
> --- a/include/linux/pagevec.h
> +++ b/include/linux/pagevec.h
> @@ -20,7 +20,7 @@
>  struct pagevec {
>         unsigned char nr;
>         bool percpu_pvec_drained;
> -       struct page *pages[PAGEVEC_SIZE];
> +       struct list_head veclist;
>  };

pagevecs are used not just for LRU.  If you want to use a list_head for
LRU then define a new structure.