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Date: Thu, 27 Sep 2012 09:20:57 +0800
From: Fengguang Wu <fengguang.wu@intel.com>
To: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        David Rientjes <rientjes@google.com>,
        Andi Kleen <andi.kleen@intel.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] kpageflags: fix wrong KPF_THP on non-huge compound
 pages
Message-ID: <20120927012057.GE7205@localhost>
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> -	else if (PageTransCompound(page))
> +	/*
> +	 * PageTransCompound can be true for non-huge compound pages (slab
> +	 * pages or pages allocated by drivers with __GFP_COMP) because it
> +	 * just checks PG_head/PG_tail, so we need to check PageLRU to make
> +	 * sure a given page is a thp, not a non-huge compound page.
> +	 */
> +	else if (PageTransCompound(page) && PageLRU(compound_trans_head(page)))
>  		u |= 1 << KPF_THP;

Reviewed-by: Fengguang Wu <fengguang.wu@intel.com>

Thanks!