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