Date: Thu, 12 Feb 2015 00:21:40 +0200
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>, linux-mm@kvack.org,
        akpm@linux-foundation.org, mhocko@suse.cz, mgorman@suse.de,
        rientjes@google.com, sasha.levin@oracle.com, hughd@google.com,
        hannes@cmpxchg.org, vbabka@suse.cz, linux-kernel@vger.kernel.org,
        riel@redhat.com
Subject: Re: [PATCH v2] mm: incorporate zero pages into transparent huge pages
Message-ID: <20150211222140.GA12928@node.dhcp.inet.fi>
References: <1423688635-4306-1-git-send-email-ebru.akagunduz@gmail.com>
 <20150211221600.GN11755@redhat.com>
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On Wed, Feb 11, 2015 at 11:16:00PM +0100, Andrea Arcangeli wrote:
> On Wed, Feb 11, 2015 at 11:03:55PM +0200, Ebru Akagunduz wrote:
> > Changes in v2:
> >  - Check zero pfn in release_pte_pages() (Andrea Arcangeli)
> 
> .. and in:
> 
> > @@ -2237,7 +2237,7 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
> >  		pte_t pteval = *_pte;
> >  		struct page *src_page;
> >  
> > -		if (pte_none(pteval)) {
> > +		if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) {
> >  			clear_user_highpage(page, address);
> >  			add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1);
> >  		} else {
> 
> __collapse_huge_page_copy, both were needed as far as I can tell.

There was is_zero_pfn(pte_pfn(pteval)) in __collapse_huge_page_copy() in
original patch.

> I haven't tested it but it's looking good.
> 
> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

-- 
 Kirill A. Shutemov
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