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Date: Mon, 16 Jan 2012 12:18:43 -0500
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Organization: NEC Corporation
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To: Andrea Arcangeli <aarcange@redhat.com>
CC: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        David Rientjes <rientjes@google.com>, Andi Kleen <andi@firstfloor.org>,
        Wu Fengguang <fengguang.wu@intel.com>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/6] pagemap: avoid splitting thp when reading /proc/pid/pagemap
References: <1326396898-5579-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1326396898-5579-2-git-send-email-n-horiguchi@ah.jp.nec.com> <20120114170026.GF3236@redhat.com> <20120115120605.GI3236@redhat.com>
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On Sun, Jan 15, 2012 at 01:06:05PM +0100, Andrea Arcangeli wrote:
> On Sat, Jan 14, 2012 at 06:00:26PM +0100, Andrea Arcangeli wrote:
> > Why don't you pass the pmd and then do "if (pmd_present(pmd))
> > page_to_pfn(pmd_page(pmd)) ? What's the argument for the cast. I'm
> 
> Of course I meant pmd_pfn above... in short as a replacement of the
> pte_pfn in your patch.
> 
> About the _stable function, I was now thinking maybe _lock suffix is
> more appropriate than _stable, because that function effectively has
> the objective of taking the page_table_lock in the most efficient way,
> and not much else other than taking the lock. Adding a comment that
> it's only safe to call with the mmap_sem held in the inline version in
> the .h file (the one that then would call the __ version in the .c
> file).

OK, I will use _lock suffix and add the comment in the next post.