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Commit 55400296 authored by Danny Segal's avatar Danny Segal
Browse files

usb: gadget: optimize sys2bam data path to use skb pool 



This patch implement a gradually growing skb pool to optimize sys2bam
UL data path. This is required to ensure that whenever we queue a usb
request to the USB core we will have a free skb to attach its buffer
to the usb request, otherwise we may lose time performance.

Change-Id: I558a5ee1a4fd08c8cfa5c93a2f856c46848ff598
Signed-off-by: default avatarNadine Toledano <nadinet@codeaurora.org>
Signed-off-by: default avatarIdo Shayevitz <idos@codeaurora.org>
Signed-off-by: default avatarDanny Segal <dsegal@codeaurora.org>
parent 5619f4da

drivers/usb/gadget/u_bam.c

+84 −8
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ struct bam_ch_info { 


	struct list_head        rx_idle;

	struct sk_buff_head	rx_skb_q;

	struct sk_buff_head	rx_skb_idle;



	struct gbam_port	*port;

	struct work_struct	write_tobam_w;
@@ -212,6 +213,71 @@ static int gbam_alloc_requests(struct usb_ep *ep, struct list_head *head, 
	return 0;

}



static struct sk_buff *gbam_alloc_skb_from_pool(struct gbam_port *port)

{

	struct bam_ch_info *d;

	unsigned long flags;

	struct sk_buff *skb;



	if (!port)

		return NULL;

	d = &port->data_ch;



	spin_lock_irqsave(&port->port_lock_ul, flags);



	if (d->rx_skb_idle.qlen == 0) {

		/*

		 * In case skb idle pool is empty, we allow to allocate more

		 * skbs so we dynamically enlarge the pool size when needed.

		 * Therefore, in steady state this dynamic allocation will

		 * stop when the pool will arrive to its optimal size.

		 */

		pr_debug("%s: allocate skb\n", __func__);

		skb = alloc_skb(bam_mux_rx_req_size + BAM_MUX_HDR, GFP_ATOMIC);

		if (!skb)

			pr_err("%s: alloc skb failed\n", __func__);

	} else {

		pr_debug("%s: pull skb from pool\n", __func__);

		skb = __skb_dequeue(&d->rx_skb_idle);

	}



	spin_unlock_irqrestore(&port->port_lock_ul, flags);



	return skb;

}



static void gbam_free_skb_to_pool(struct gbam_port *port, struct sk_buff *skb)

{

	struct bam_ch_info *d;

	unsigned long flags;



	if (!port)

		return;

	d = &port->data_ch;



	spin_lock_irqsave(&port->port_lock_ul, flags);

	skb->len = 0;

	skb_reset_tail_pointer(skb);

	__skb_queue_tail(&d->rx_skb_idle, skb);

	spin_unlock_irqrestore(&port->port_lock_ul, flags);

}



static void gbam_free_rx_skb_idle_list(struct gbam_port *port)

{

	struct bam_ch_info *d;

	struct sk_buff *skb;



	if (!port)

		return;

	d = &port->data_ch;



	while (d->rx_skb_idle.qlen > 0) {

		skb = __skb_dequeue(&d->rx_skb_idle);

		dev_kfree_skb_any(skb);

	}

}





/*----- sys2bam towards the IPA --------------- */

static void gbam_ipa_sys2bam_notify_cb(void *priv, enum ipa_dp_evt_type event,

		unsigned long data)
@@ -356,7 +422,7 @@ void gbam_data_write_done(void *p, struct sk_buff *skb) 
	if (!skb)

		return;



	dev_kfree_skb_any(skb);

	gbam_free_skb_to_pool(port, skb);



	spin_lock_irqsave(&port->port_lock_ul, flags);
@@ -412,7 +478,9 @@ static void gbam_data_write_tobam(struct work_struct *w) 
			d->pending_with_bam--;

			d->to_modem--;

			d->tomodem_drp_cnt++;

			dev_kfree_skb_any(skb);

			spin_unlock_irqrestore(&port->port_lock_ul, flags);

			gbam_free_skb_to_pool(port, skb);

			spin_lock_irqsave(&port->port_lock_ul, flags);

			break;

		}

		if (d->pending_with_bam > d->max_num_pkts_pending_with_bam)
@@ -486,7 +554,7 @@ gbam_epout_complete(struct usb_ep *ep, struct usb_request *req) 
	case -ECONNRESET:

	case -ESHUTDOWN:

		/* cable disconnection */

		dev_kfree_skb_any(skb);

		gbam_free_skb_to_pool(port, skb);

		req->buf = 0;

		usb_ep_free_request(ep, req);

		return;
@@ -495,7 +563,7 @@ gbam_epout_complete(struct usb_ep *ep, struct usb_request *req) 
			pr_err("%s: %s response error %d, %d/%d\n",

				__func__, ep->name, status,

				req->actual, req->length);

		dev_kfree_skb_any(skb);

		gbam_free_skb_to_pool(port, skb);

		break;

	}
@@ -520,7 +588,7 @@ gbam_epout_complete(struct usb_ep *ep, struct usb_request *req) 
	}

	spin_unlock(&port->port_lock_ul);



	skb = alloc_skb(bam_mux_rx_req_size + BAM_MUX_HDR, GFP_ATOMIC);

	skb = gbam_alloc_skb_from_pool(port);

	if (!skb) {

		spin_lock(&port->port_lock_ul);

		list_add_tail(&req->list, &d->rx_idle);
@@ -535,7 +603,7 @@ gbam_epout_complete(struct usb_ep *ep, struct usb_request *req) 


	status = usb_ep_queue(ep, req, GFP_ATOMIC);

	if (status) {

		dev_kfree_skb_any(skb);

		gbam_free_skb_to_pool(port, skb);



		if (printk_ratelimit())

			pr_err("%s: data rx enqueue err %d\n",
@@ -587,7 +655,9 @@ static void gbam_start_rx(struct gbam_port *port) 


		req = list_first_entry(&d->rx_idle, struct usb_request, list);



		skb = alloc_skb(bam_mux_rx_req_size + BAM_MUX_HDR, GFP_ATOMIC);

		spin_unlock_irqrestore(&port->port_lock_ul, flags);

		skb = gbam_alloc_skb_from_pool(port);

		spin_lock_irqsave(&port->port_lock_ul, flags);

		if (!skb)

			break;

		skb_reserve(skb, BAM_MUX_HDR);
@@ -601,7 +671,9 @@ static void gbam_start_rx(struct gbam_port *port) 
		ret = usb_ep_queue(ep, req, GFP_ATOMIC);

		spin_lock_irqsave(&port->port_lock_ul, flags);

		if (ret) {

			dev_kfree_skb_any(skb);

			spin_unlock_irqrestore(&port->port_lock_ul, flags);

			gbam_free_skb_to_pool(port, skb);

			spin_lock_irqsave(&port->port_lock_ul, flags);



			if (printk_ratelimit())

				pr_err("%s: rx queue failed %d\n",
@@ -822,6 +894,8 @@ static void gbam_free_buffers(struct gbam_port *port) 
	while ((skb = __skb_dequeue(&d->rx_skb_q)))

		dev_kfree_skb_any(skb);



	gbam_free_rx_skb_idle_list(port);



free_buf_out:

	spin_unlock(&port->port_lock_dl);

	spin_unlock_irqrestore(&port->port_lock_ul, flags);
@@ -1341,6 +1415,7 @@ static int gbam_port_alloc(int portno) 
	INIT_WORK(&d->write_tohost_w, gbam_write_data_tohost_w);

	skb_queue_head_init(&d->tx_skb_q);

	skb_queue_head_init(&d->rx_skb_q);

	skb_queue_head_init(&d->rx_skb_idle);

	d->id = bam_ch_ids[portno];



	bam_ports[portno].port = port;
@@ -1386,6 +1461,7 @@ static int gbam2bam_port_alloc(int portno) 


	/* UL workaround requirements */

	skb_queue_head_init(&d->rx_skb_q);

	skb_queue_head_init(&d->rx_skb_idle);

	INIT_LIST_HEAD(&d->rx_idle);

	INIT_WORK(&d->write_tobam_w, gbam_data_write_tobam);