linux-kernel - Re: [PATCH 13/15] mm/hmm: factor out pte and pmd handling to simplify hmm_vma_walk

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Message-ID: <6ded8a12-1522-3270-602c-bafc7e823758@nvidia.com>
Date:   Wed, 21 Mar 2018 15:36:01 -0700
From:   John Hubbard <jhubbard@...dia.com>
To:     Jerome Glisse <jglisse@...hat.com>
CC:     <linux-mm@...ck.org>, Andrew Morton <akpm@...ux-foundation.org>,
        <linux-kernel@...r.kernel.org>,
        Evgeny Baskakov <ebaskakov@...dia.com>,
        Ralph Campbell <rcampbell@...dia.com>,
        Mark Hairgrove <mhairgrove@...dia.com>
Subject: Re: [PATCH 13/15] mm/hmm: factor out pte and pmd handling to simplify
 hmm_vma_walk_pmd()

On 03/21/2018 08:08 AM, Jerome Glisse wrote:
> On Tue, Mar 20, 2018 at 10:07:29PM -0700, John Hubbard wrote:
>> On 03/19/2018 07:00 PM, jglisse@...hat.com wrote:
>>> From: Jérôme Glisse <jglisse@...hat.com>

<snip>
 
>>> +static int hmm_vma_handle_pmd(struct mm_walk *walk,
>>> +			      unsigned long addr,
>>> +			      unsigned long end,
>>> +			      uint64_t *pfns,
>>
>> Hi Jerome,
>>
>> Nice cleanup, it makes it much easier to follow the code now.
>>
>> Let's please rename the pfns argument above to "pfn", because in this
>> helper (and the _pte helper too), there is only one pfn involved, rather
>> than an array of them.
> 
> This is only true to handle_pte, for handle_pmd it will go over several
> pfn entries. But they will all get fill with same value modulo pfn which
> will increase monotically (ie same flag as pmd permissions apply to all
> entries).

oops, yes you are right about handle_pmd.

> 
> Note sure s/pfns/pfn for hmm_vma_handle_pte() warrant a respin.

Probably not, unless there is some other reason to respin. Anyway, this patch
looks good either way, I think, so you can still add:

Reviewed-by: John Hubbard <jhubbard@...dia.com>

thanks,
-- 
John Hubbard
NVIDIA