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Date:   Fri, 31 May 2019 19:25:24 +0300
From:   Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
To:     Jesper Dangaard Brouer <brouer@redhat.com>
Cc:     grygorii.strashko@ti.com, hawk@kernel.org, davem@davemloft.net,
        ast@kernel.org, linux-kernel@vger.kernel.org,
        linux-omap@vger.kernel.org, xdp-newbies@vger.kernel.org,
        ilias.apalodimas@linaro.org, netdev@vger.kernel.org,
        daniel@iogearbox.net, jakub.kicinski@netronome.com,
        john.fastabend@gmail.com
Subject: Re: [PATCH v2 net-next 7/7] net: ethernet: ti: cpsw: add XDP support
Message-ID: <20190531162523.GA3694@khorivan>
Mail-Followup-To: Jesper Dangaard Brouer <brouer@redhat.com>,
        grygorii.strashko@ti.com, hawk@kernel.org, davem@davemloft.net,
        ast@kernel.org, linux-kernel@vger.kernel.org,
        linux-omap@vger.kernel.org, xdp-newbies@vger.kernel.org,
        ilias.apalodimas@linaro.org, netdev@vger.kernel.org,
        daniel@iogearbox.net, jakub.kicinski@netronome.com,
        john.fastabend@gmail.com
References: <20190530182039.4945-1-ivan.khoronzhuk@linaro.org>
 <20190530182039.4945-8-ivan.khoronzhuk@linaro.org>
 <20190531174643.4be8b27f@carbon>
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On Fri, May 31, 2019 at 05:46:43PM +0200, Jesper Dangaard Brouer wrote:

Hi Jesper,

>
>Hi Ivan,
>
>From below code snippets, it looks like you only allocated 1 page_pool
>and sharing it with several RX-queues, as I don't have the full context
>and don't know this driver, I might be wrong?
>
>To be clear, a page_pool object is needed per RX-queue, as it is
>accessing a small RX page cache (which protected by NAPI/softirq).

There is one RX interrupt and one RX NAPI for all rx channels.

>
>On Thu, 30 May 2019 21:20:39 +0300
>Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:
>
>> @@ -1404,6 +1711,14 @@ static int cpsw_ndo_open(struct net_device *ndev)
>>  			enable_irq(cpsw->irqs_table[0]);
>>  		}
>>
>> +		pool_size = cpdma_get_num_rx_descs(cpsw->dma);
>> +		cpsw->page_pool = cpsw_create_page_pool(cpsw, pool_size);
>> +		if (IS_ERR(cpsw->page_pool)) {
>> +			ret = PTR_ERR(cpsw->page_pool);
>> +			cpsw->page_pool = NULL;
>> +			goto err_cleanup;
>> +		}
>
>On Thu, 30 May 2019 21:20:39 +0300
>Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:
>
>> @@ -675,10 +742,33 @@ int cpsw_set_ringparam(struct net_device *ndev,
>>  	if (cpsw->usage_count)
>>  		cpdma_chan_split_pool(cpsw->dma);
>>
>> +	for (i = 0; i < cpsw->data.slaves; i++) {
>> +		struct net_device *ndev = cpsw->slaves[i].ndev;
>> +
>> +		if (!(ndev && netif_running(ndev)))
>> +			continue;
>> +
>> +		cpsw_xdp_unreg_rxqs(netdev_priv(ndev));
>> +	}
>> +
>> +	page_pool_destroy(cpsw->page_pool);
>> +	cpsw->page_pool = pool;
>> +
>
>On Thu, 30 May 2019 21:20:39 +0300
>Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:
>
>> +void cpsw_xdp_unreg_rxqs(struct cpsw_priv *priv)
>> +{
>> +	struct cpsw_common *cpsw = priv->cpsw;
>> +	int i;
>> +
>> +	for (i = 0; i < cpsw->rx_ch_num; i++)
>> +		xdp_rxq_info_unreg(&priv->xdp_rxq[i]);
>> +}
>
>
>On Thu, 30 May 2019 21:20:39 +0300
>Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:
>
>> +int cpsw_xdp_reg_rxq(struct cpsw_priv *priv, int ch)
>> +{
>> +	struct xdp_rxq_info *xdp_rxq = &priv->xdp_rxq[ch];
>> +	struct cpsw_common *cpsw = priv->cpsw;
>> +	int ret;
>> +
>> +	ret = xdp_rxq_info_reg(xdp_rxq, priv->ndev, ch);
>> +	if (ret)
>> +		goto err_cleanup;
>> +
>> +	ret = xdp_rxq_info_reg_mem_model(xdp_rxq, MEM_TYPE_PAGE_POOL,
>> +					 cpsw->page_pool);
>> +	if (ret)
>> +		goto err_cleanup;
>> +
>> +	return 0;
>
>
>
>-- 
>Best regards,
>  Jesper Dangaard Brouer
>  MSc.CS, Principal Kernel Engineer at Red Hat
>  LinkedIn: http://www.linkedin.com/in/brouer

-- 
Regards,
Ivan Khoronzhuk