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Subject: Re: [PATCH v21 05/19] mm/vmscan: remove unnecessary lruvec adding
To:     Alex Shi <alex.shi@linux.alibaba.com>, akpm@linux-foundation.org,
        mgorman@techsingularity.net, tj@kernel.org, hughd@google.com,
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        kirill@shutemov.name, alexander.duyck@gmail.com,
        rong.a.chen@intel.com, mhocko@suse.com, vdavydov.dev@gmail.com,
        shy828301@gmail.com
References: <1604566549-62481-1-git-send-email-alex.shi@linux.alibaba.com>
 <1604566549-62481-6-git-send-email-alex.shi@linux.alibaba.com>
From:   Vlastimil Babka <vbabka@suse.cz>
Message-ID: <c07810ed-31b7-7b9b-9638-cfc7574f4a2d@suse.cz>
Date:   Wed, 11 Nov 2020 13:36:43 +0100
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On 11/5/20 9:55 AM, Alex Shi wrote:
> We don't have to add a freeable page into lru and then remove from it.
> This change saves a couple of actions and makes the moving more clear.
> 
> The SetPageLRU needs to be kept before put_page_testzero for list
> integrity, otherwise:
> 
>    #0 move_pages_to_lru             #1 release_pages
>    if !put_page_testzero
>       			           if (put_page_testzero())
>       			              !PageLRU //skip lru_lock
>       SetPageLRU()
>       list_add(&page->lru,)
>                                           list_add(&page->lru,)
> 
> [akpm@linux-foundation.org: coding style fixes]
> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> Acked-by: Hugh Dickins <hughd@google.com>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org

Acked-by: Vlastimil Babka <vbabka@suse.cz>

Nice cleanup!