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Subject: Re: [PATCH 31/31] mm, vmstat: Remove zone and node double accounting
 by approximating retries
To: Mel Gorman <mgorman@techsingularity.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux-MM <linux-mm@kvack.org>
References: <1467403299-25786-1-git-send-email-mgorman@techsingularity.net>
 <1467403299-25786-32-git-send-email-mgorman@techsingularity.net>
Cc: Rik van Riel <riel@surriel.com>, Vlastimil Babka <vbabka@suse.cz>,
        Johannes Weiner <hannes@cmpxchg.org>,
        LKML <linux-kernel@vger.kernel.org>
From: Dave Hansen <dave.hansen@intel.com>
Message-ID: <577D4A24.1090800@intel.com>
Date: Wed, 6 Jul 2016 11:12:52 -0700
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On 07/01/2016 01:01 PM, Mel Gorman wrote:
> +#ifdef CONFIG_HIGHMEM
> +extern unsigned long highmem_file_pages;
> +
> +static inline void acct_highmem_file_pages(int zid, enum lru_list lru,
> +							int nr_pages)
> +{
> +	if (is_highmem_idx(zid) && is_file_lru(lru))
> +		highmem_file_pages += nr_pages;
> +}
> +#else

Shouldn't highmem_file_pages technically be an atomic_t (or atomic64_t)?
 We could have highmem on two nodes which take two different LRU locks.