netdev - Re: [PATCH v3 net-next 08/14] mlx4: use order-0 pages for RX

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Message-ID: <CANn89iLkPB_Dx1L2dFfwOoeXOmPhu_C3OO2yqZi8+Rvjr=-EtA@mail.gmail.com>
Date:   Mon, 13 Feb 2017 13:09:58 -0800
From:   Eric Dumazet <edumazet@...gle.com>
To:     Alexander Duyck <alexander.duyck@...il.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        netdev <netdev@...r.kernel.org>,
        Tariq Toukan <tariqt@...lanox.com>,
        Martin KaFai Lau <kafai@...com>,
        Saeed Mahameed <saeedm@...lanox.com>,
        Willem de Bruijn <willemb@...gle.com>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Brenden Blanco <bblanco@...mgrid.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH v3 net-next 08/14] mlx4: use order-0 pages for RX

On Mon, Feb 13, 2017 at 12:51 PM, Alexander Duyck
<alexander.duyck@...il.com> wrote:
> On Mon, Feb 13, 2017 at 11:58 AM, Eric Dumazet <edumazet@...gle.com> wrote:

>> +                              PAGE_SIZE, priv->dma_dir);
>>                 page = page_alloc->page;
>>                 /* Revert changes done by mlx4_alloc_pages */
>> -               page_ref_sub(page, page_alloc->page_size /
>> +               page_ref_sub(page, PAGE_SIZE /
>>                                    priv->frag_info[i].frag_stride - 1);
>>                 put_page(page);
>>                 page_alloc->page = NULL;
>
> You can probably simplify this by using __page_frag_cache_drain since
> that way you can just doe the sub and test for the whole set instead
> of doing N - 1 and 1.

Well, we remove this anyway in following patch ;)