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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Dave Hansen <dave@sr71.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>, Hugh Dickins <hughd@google.com>,
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        Andi Kleen <ak@linux.intel.com>,
        Matthew Wilcox <matthew.r.wilcox@intel.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Hillf Danton <dhillf@gmail.com>, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Subject: Re: [PATCHv4 27/39] x86-64, mm: proper alignment mappings with
 hugepages
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Message-Id: <20130625145655.68DCBE0090@blue.fi.intel.com>
Date: Tue, 25 Jun 2013 17:56:55 +0300 (EEST)
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Dave Hansen wrote:
> On 05/11/2013 06:23 PM, Kirill A. Shutemov wrote:
> > +static inline unsigned long mapping_align_mask(struct address_space *mapping)
> > +{
> > +	if (mapping_can_have_hugepages(mapping))
> > +		return PAGE_MASK & ~HPAGE_MASK;
> > +	return get_align_mask();
> > +}
> 
> get_align_mask() appears to be a bit more complicated to me than just a
> plain old mask.  Are you sure you don't need to pick up any of its
> behavior for the mapping_can_have_hugepages() case?

get_align_mask() never returns more strict mask then we do in
mapping_can_have_hugepages() case.

I can modify it this way:

        unsigned long mask = get_align_mask();

        if (mapping_can_have_hugepages(mapping))
                mask &= PAGE_MASK & ~HPAGE_MASK;
        return mask;

But it looks more confusing for me. What do you think?

-- 
 Kirill A. Shutemov