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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Wed, 12 Sep 2018 09:50:34 -0700
Message-ID: <CAPcyv4gEDwp8Xh4_E8RNBC_OqstwhqxkZOpvYjWd_siB4C=BEQ@mail.gmail.com>
Subject: Re: [PATCH 3/4] mm: Defer ZONE_DEVICE page initialization to the
 point where we init pgmap
To:     Alexander Duyck <alexander.duyck@gmail.com>
Cc:     Pavel.Tatashin@microsoft.com, linux-mm <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-nvdimm <linux-nvdimm@lists.01.org>,
        Michal Hocko <mhocko@suse.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Ingo Molnar <mingo@kernel.org>,
        Dave Hansen <dave.hansen@intel.com>,
        =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Logan Gunthorpe <logang@deltatee.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
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On Wed, Sep 12, 2018 at 8:48 AM, Alexander Duyck
<alexander.duyck@gmail.com> wrote:
> On Wed, Sep 12, 2018 at 6:59 AM Pasha Tatashin
> <Pavel.Tatashin@microsoft.com> wrote:
>>
>> Hi Alex,
>
> Hi Pavel,
>
>> Please re-base on linux-next,  memmap_init_zone() has been updated there
>> compared to mainline. You might even find a way to unify some parts of
>> memmap_init_zone and memmap_init_zone_device as memmap_init_zone() is a
>> lot simpler now.
>
> This patch applied to the linux-next tree with only a little bit of
> fuzz. It looks like it is mostly due to some code you had added above
> the function as well. I have updated this patch so that it will apply
> to both linux and linux-next by just moving the new function to
> underneath memmap_init_zone instead of above it.
>
>> I think __init_single_page() should stay local to page_alloc.c to keep
>> the inlining optimization.
>
> I agree. In addition it will make pulling common init together into
> one space easier. I would rather not have us create an opportunity for
> things to further diverge by making it available for anybody to use.

I'll buy the inline argument for keeping the new routine in
page_alloc.c, but I otherwise do not see the divergence danger or
"making __init_single_page() available for anybody" given the the
declaration is limited in scope to a mm/ local header file.