linux-kernel - Re: [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to optimize signaling the host

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Message-ID: <1431323894.2884.4.camel@perches.com>
Date:	Sun, 10 May 2015 22:58:14 -0700
From:	Joe Perches <joe@...ches.com>
To:	"K. Y. Srinivasan" <kys@...rosoft.com>
Cc:	davem@...emloft.net, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, devel@...uxdriverproject.org,
	olaf@...fle.de, apw@...onical.com, jasowang@...hat.com
Subject: Re: [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to
 optimize signaling the host

On Sun, 2015-05-10 at 21:08 -0700, K. Y. Srinivasan wrote:
> Based on the information given to this driver (via the xmit_more skb flag),
> we can defer signaling the host if more packets are on the way. This will help
> make the host more efficient since it can potentially process a larger batch of
> packets. Implement this optimization.

trivia:

I think that indirecting VMBUS_DATA_PACKET_FLAG_COMPLETTION_REQUESTED
into a non-const temporary isn't very useful.

Whenever overly long identifiers like VMBUS_<FOO> is used,
I think that it'd be better to use it directly and ignore
80 column warnings.

Same with the "sizeof(struct nvsp_message)" on two lines.

> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
[]
> @@ -743,6 +743,8 @@ static inline int netvsc_send_pkt(
>  	u64 req_id;
>  	int ret;
>  	struct hv_page_buffer *pgbuf;
> +	u32 vmbus_flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
> +	u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);
[]
> @@ -769,30 +771,41 @@ static inline int netvsc_send_pkt(
[]
> +		ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
> +						      pgbuf,
> +						      packet->page_buf_cnt,
> +						      &nvmsg,
> +						      sizeof(struct
> +							     nvsp_message),
> +						      req_id,
> +						      vmbus_flags,
> +						      !packet->xmit_more);

[]

>  			netif_tx_stop_queue(netdev_get_tx_queue(
>  					    ndev, q_idx));

This could be on one line too.


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