mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-11-19 19:37:30 +02:00
f21c103e5a
Also remove a duplicate patch from lantiq (already in generic). git-svn-id: svn://svn.openwrt.org/openwrt/trunk@31158 3c298f89-4303-0410-b956-a3cf2f4a3e73
76 lines
2.7 KiB
Diff
76 lines
2.7 KiB
Diff
For every transmitted packet, ppp_start_xmit() will stop the netdev
|
|
queue and then, if appropriate, restart it. This causes the TX softirq
|
|
to run, entirely gratuitously.
|
|
|
|
This is "only" a waste of CPU time in the normal case, but it's actively
|
|
harmful when the PPP device is a TEQL slave — the wakeup will cause the
|
|
offending device to receive the next TX packet from the TEQL queue, when
|
|
it *should* have gone to the next slave in the list. We end up seeing
|
|
large bursts of packets on just *one* slave device, rather than using
|
|
the full available bandwidth over all slaves.
|
|
|
|
This patch fixes the problem by *not* unconditionally stopping the queue
|
|
in ppp_start_xmit(). It adds a return value from ppp_xmit_process()
|
|
which indicates whether the queue should be stopped or not.
|
|
|
|
It *doesn't* remove the call to netif_wake_queue() from
|
|
ppp_xmit_process(), because other code paths (especially from
|
|
ppp_output_wakeup()) need it there and it's messy to push it out to the
|
|
other callers to do it based on the return value. So we leave it in
|
|
place — it's a no-op in the case where the queue wasn't stopped, so it's
|
|
harmless in the TX path.
|
|
|
|
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
|
|
|
|
--- a/drivers/net/ppp/ppp_generic.c
|
|
+++ b/drivers/net/ppp/ppp_generic.c
|
|
@@ -235,7 +235,7 @@ struct ppp_net {
|
|
/* Prototypes. */
|
|
static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
|
|
struct file *file, unsigned int cmd, unsigned long arg);
|
|
-static void ppp_xmit_process(struct ppp *ppp);
|
|
+static int ppp_xmit_process(struct ppp *ppp);
|
|
static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
|
|
static void ppp_push(struct ppp *ppp);
|
|
static void ppp_channel_push(struct channel *pch);
|
|
@@ -968,9 +968,9 @@ ppp_start_xmit(struct sk_buff *skb, stru
|
|
proto = npindex_to_proto[npi];
|
|
put_unaligned_be16(proto, pp);
|
|
|
|
- netif_stop_queue(dev);
|
|
skb_queue_tail(&ppp->file.xq, skb);
|
|
- ppp_xmit_process(ppp);
|
|
+ if (!ppp_xmit_process(ppp))
|
|
+ netif_stop_queue(dev);
|
|
return NETDEV_TX_OK;
|
|
|
|
outf:
|
|
@@ -1048,10 +1048,11 @@ static void ppp_setup(struct net_device
|
|
* Called to do any work queued up on the transmit side
|
|
* that can now be done.
|
|
*/
|
|
-static void
|
|
+static int
|
|
ppp_xmit_process(struct ppp *ppp)
|
|
{
|
|
struct sk_buff *skb;
|
|
+ int ret = 0;
|
|
|
|
ppp_xmit_lock(ppp);
|
|
if (!ppp->closing) {
|
|
@@ -1061,10 +1062,13 @@ ppp_xmit_process(struct ppp *ppp)
|
|
ppp_send_frame(ppp, skb);
|
|
/* If there's no work left to do, tell the core net
|
|
code that we can accept some more. */
|
|
- if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
|
|
+ if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq)) {
|
|
netif_wake_queue(ppp->dev);
|
|
+ ret = 1;
|
|
+ }
|
|
}
|
|
ppp_xmit_unlock(ppp);
|
|
+ return ret;
|
|
}
|
|
|
|
static inline struct sk_buff *
|