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f_phonet: use page-sized rather than MTU-sized RX buffers

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Instead of a large (physically) linear buffer, we generate a set of
paged sk_buff, so no extra memory copy is involved. This removes
high-order allocations and saves quite a bit of memory. Phonet MTU is
65541 bytes, so the two buffers were padded to 128 kilo-bytes each.
Now, we create 17 page buffers, almost a 75% memory use reduction.

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Rémi Denis-Courmont 2009-08-06 21:56:44 +00:00 committed by David S. Miller
parent 5da63cc4b2
commit b91cd14408
1 changed files with 51 additions and 26 deletions
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77
drivers/usb/gadget/f_phonet.c
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@ -35,6 +35,10 @@
#include "u_phonet.h"
#define PN_MEDIA_USB 0x1B
#define MAXPACKET 512
#if (PAGE_SIZE % MAXPACKET)
#error MAXPACKET must divide PAGE_SIZE!
#endif
/*-------------------------------------------------------------------------*/
@ -45,6 +49,10 @@ struct phonet_port {
struct f_phonet {
struct usb_function function;
struct {
struct sk_buff *skb;
spinlock_t lock;
} rx;
struct net_device *dev;
struct usb_ep *in_ep, *out_ep;
@ -52,7 +60,7 @@ struct f_phonet {
struct usb_request *out_reqv[0];
};
static int phonet_rxq_size = 2;
static int phonet_rxq_size = 17;
static inline struct f_phonet *func_to_pn(struct usb_function *f)
{
@ -138,7 +146,7 @@ pn_hs_sink_desc = {
.bEndpointAddress = USB_DIR_OUT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
.wMaxPacketSize = cpu_to_le16(MAXPACKET),
};
static struct usb_endpoint_descriptor
@ -298,21 +306,21 @@ static void pn_net_setup(struct net_device *dev)
static int
pn_rx_submit(struct f_phonet *fp, struct usb_request *req, gfp_t gfp_flags)
{
struct sk_buff *skb;
const size_t size = fp->dev->mtu;
struct net_device *dev = fp->dev;
struct page *page;
int err;
skb = alloc_skb(size, gfp_flags);
if (!skb)
page = __netdev_alloc_page(dev, gfp_flags);
if (!page)
return -ENOMEM;
req->buf = skb->data;
req->length = size;
req->context = skb;
req->buf = page_address(page);
req->length = PAGE_SIZE;
req->context = page;
err = usb_ep_queue(fp->out_ep, req, gfp_flags);
if (unlikely(err))
dev_kfree_skb_any(skb);
netdev_free_page(dev, page);
return err;
}
@ -320,25 +328,37 @@ static void pn_rx_complete(struct usb_ep *ep, struct usb_request *req)
{
struct f_phonet *fp = ep->driver_data;
struct net_device *dev = fp->dev;
struct sk_buff *skb = req->context;
struct page *page = req->context;
struct sk_buff *skb;
unsigned long flags;
int status = req->status;
switch (status) {
case 0:
if (unlikely(!netif_running(dev)))
break;
if (unlikely(req->actual < 1))
break;
skb_put(skb, req->actual);
skb->protocol = htons(ETH_P_PHONET);
skb_reset_mac_header(skb);
__skb_pull(skb, 1);
skb->dev = dev;
dev->stats.rx_packets++;
dev->stats.rx_bytes += skb->len;
spin_lock_irqsave(&fp->rx.lock, flags);
skb = fp->rx.skb;
if (!skb)
skb = fp->rx.skb = netdev_alloc_skb(dev, 12);
if (req->actual < req->length) /* Last fragment */
fp->rx.skb = NULL;
spin_unlock_irqrestore(&fp->rx.lock, flags);
netif_rx(skb);
skb = NULL;
if (unlikely(!skb))
break;
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, 0,
req->actual);
page = NULL;
if (req->actual < req->length) { /* Last fragment */
skb->protocol = htons(ETH_P_PHONET);
skb_reset_mac_header(skb);
pskb_pull(skb, 1);
skb->dev = dev;
dev->stats.rx_packets++;
dev->stats.rx_bytes += skb->len;
netif_rx(skb);
}
break;
/* Do not resubmit in these cases: */
@ -356,8 +376,8 @@ static void pn_rx_complete(struct usb_ep *ep, struct usb_request *req)
break;
}
if (skb)
dev_kfree_skb_any(skb);
if (page)
netdev_free_page(dev, page);
if (req)
pn_rx_submit(fp, req, GFP_ATOMIC);
}
@ -375,6 +395,10 @@ static void __pn_reset(struct usb_function *f)
usb_ep_disable(fp->out_ep);
usb_ep_disable(fp->in_ep);
if (fp->rx.skb) {
dev_kfree_skb_irq(fp->rx.skb);
fp->rx.skb = NULL;
}
}
static int pn_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
@ -573,6 +597,7 @@ int __init phonet_bind_config(struct usb_configuration *c)
fp->function.set_alt = pn_set_alt;
fp->function.get_alt = pn_get_alt;
fp->function.disable = pn_disconnect;
spin_lock_init(&fp->rx.lock);
err = usb_add_function(c, &fp->function);
if (err)