Date: Thu, 18 Nov 2010 12:40:30 +0000
From: Mel Gorman <mel@csn.ul.ie>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: linux-mm@kvack.org, Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>,
        Adam Litke <agl@us.ibm.com>, Avi Kivity <avi@redhat.com>,
        Hugh Dickins <hugh.dickins@tiscali.co.uk>,
        Rik van Riel <riel@redhat.com>, Dave Hansen <dave@linux.vnet.ibm.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Ingo Molnar <mingo@elte.hu>, Mike Travis <travis@sgi.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        Christoph Lameter <cl@linux-foundation.org>,
        Chris Wright <chrisw@sous-sol.org>, bpicco@redhat.com,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Balbir Singh <balbir@linux.vnet.ibm.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
        Chris Mason <chris.mason@oracle.com>, Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH 08 of 66] fix bad_page to show the real reason the page
	is bad
Message-ID: <20101118124030.GL8135@csn.ul.ie>
References: <patchbomb.1288798055@v2.random> <412c4bbbe7738978ce73.1288798063@v2.random>
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On Wed, Nov 03, 2010 at 04:27:43PM +0100, Andrea Arcangeli wrote:
> From: Andrea Arcangeli <aarcange@redhat.com>
> 
> page_count shows the count of the head page, but the actual check is done on
> the tail page, so show what is really being checked.
> 
> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
> Acked-by: Rik van Riel <riel@redhat.com>
> Acked-by: Mel Gorman <mel@csn.ul.ie>

This can be sent on its own as it's not really related to THP.

> ---
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5564,7 +5564,7 @@ void dump_page(struct page *page)
>  {
>  	printk(KERN_ALERT
>  	       "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
> -		page, page_count(page), page_mapcount(page),
> +		page, atomic_read(&page->_count), page_mapcount(page),
>  		page->mapping, page->index);
>  	dump_page_flags(page->flags);
>  }
> 

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab
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