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Date: Wed, 30 Jul 2008 22:50:37 +0200
From: Jarek Poplawski <jarkao2@...il.com>
To: Patrick McHardy <kaber@...sh.net>
Cc: David Miller <davem@...emloft.net>, jussi.kivilinna@...et.fi,
netdev@...r.kernel.org
Subject: Re: [PATCH v2 2/3] net_sched: Add accessor function for packet
length for qdiscs
Patrick McHardy wrote, On 07/30/2008 01:52 PM:
> David Miller wrote:
>> From: Patrick McHardy <kaber@...sh.net>
>> Date: Wed, 30 Jul 2008 13:40:22 +0200
>>
>>> The reason why it translates it at all seems to be to not increase
>>> the drops counter. Within a single qdisc this could be avoided by
>>> other means easily, upper qdiscs would still increase the counter
>>> when we return anything besides NET_XMIT_SUCCESS though.
>>>
>>> This means we need a new NET_XMIT return value to indicate this to
>>> the upper qdiscs. So I'd suggest to introduce NET_XMIT_STOLEN,
>>> return that to upper qdiscs and translate it to NET_XMIT_SUCCESS
>>> in dev_queue_xmit, similar to NET_XMIT_BYPASS.
>> Maybe these NET_XMIT_* values being passed around should be a set of
>> bits.
>>
>> They could be composed of base meanings, combined with specific
>> attributes.
>>
>> So you could say "NET_XMIT_DROP | __NET_XMIT_NO_DROP_COUNT"
>>
>> The attributes get masked out by the top-level ->enqueue() caller,
>> such that the base meanings are the only thing that make their
>> way up into the stack.
>>
>> If it's only about communication within the qdisc tree, let's
>> simply code it that way.
>
> Thats a good suggestion. I think this should work.
I hope, I didn't misunderstood who is expected to do this, so here is
my preliminary proposal. I guess, I did misunderstood some details,
so it's not final...
BTW, htb_enqueue()/requeue() is unfinished because it will conflict
with David's patch...
Any suggestions are welcome.
Thanks,
Jarek P.
---
include/linux/netdevice.h | 1 +
include/net/sch_generic.h | 15 ++++++++++++++-
net/sched/sch_atm.c | 12 +++++++-----
net/sched/sch_cbq.c | 16 ++++++++++------
net/sched/sch_dsmark.c | 8 +++++---
net/sched/sch_hfsc.c | 8 +++++---
net/sched/sch_htb.c | 2 +-
net/sched/sch_prio.c | 8 +++++---
net/sched/sch_sfq.c | 2 +-
9 files changed, 49 insertions(+), 23 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index b4d056c..188e4e4 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -64,6 +64,7 @@ struct wireless_dev;
#define NET_XMIT_BYPASS 4 /* packet does not leave via dequeue;
(TC use only - dev_queue_xmit
returns this as NET_XMIT_SUCCESS) */
+#define NET_XMIT_MASK 0xFFFF /* qdisc flags in net/sch_generic.h */
/* Backlog congestion levels */
#define NET_RX_SUCCESS 0 /* keep 'em coming, baby */
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index b5f40d7..b79bd04 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -331,6 +331,19 @@ static inline unsigned int qdisc_pkt_len(struct sk_buff *skb)
return qdisc_skb_cb(skb)->pkt_len;
}
+#ifdef CONFIG_NET_CLS_ACT
+/* additional qdisc xmit flags */
+enum net_xmit_qdisc_t
+{
+ __NET_XMIT_STOLEN = NET_XMIT_MASK + 1,
+};
+
+#define net_xmit_drop_count(e) ((e) & __NET_XMIT_STOLEN ? 0 : 1)
+
+#else
+#define net_xmit_drop_count(e) (1)
+#endif
+
static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
#ifdef CONFIG_NET_SCHED
@@ -343,7 +356,7 @@ static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
static inline int qdisc_enqueue_root(struct sk_buff *skb, struct Qdisc *sch)
{
qdisc_skb_cb(skb)->pkt_len = skb->len;
- return qdisc_enqueue(skb, sch);
+ return qdisc_enqueue(skb, sch) & NET_XMIT_MASK;
}
static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
index 6b517b9..27dd773 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -415,7 +415,7 @@ static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
kfree_skb(skb);
- return NET_XMIT_SUCCESS;
+ return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
kfree_skb(skb);
goto drop;
@@ -432,9 +432,11 @@ static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
ret = qdisc_enqueue(skb, flow->q);
if (ret != 0) {
drop: __maybe_unused
- sch->qstats.drops++;
- if (flow)
- flow->qstats.drops++;
+ if (net_xmit_drop_count(ret)) {
+ sch->qstats.drops++;
+ if (flow)
+ flow->qstats.drops++;
+ }
return ret;
}
sch->bstats.bytes += qdisc_pkt_len(skb);
@@ -530,7 +532,7 @@ static int atm_tc_requeue(struct sk_buff *skb, struct Qdisc *sch)
if (!ret) {
sch->q.qlen++;
sch->qstats.requeues++;
- } else {
+ } else if (net_xmit_drop_count(ret)) {
sch->qstats.drops++;
p->link.qstats.drops++;
}
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 14954bf..00a0af6 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -256,7 +256,7 @@ cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
switch (result) {
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
- *qerr = NET_XMIT_SUCCESS;
+ *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return NULL;
case TC_ACT_RECLASSIFY:
@@ -397,9 +397,11 @@ cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
return ret;
}
- sch->qstats.drops++;
- cbq_mark_toplevel(q, cl);
- cl->qstats.drops++;
+ if (net_xmit_drop_count(ret)) {
+ sch->qstats.drops++;
+ cbq_mark_toplevel(q, cl);
+ cl->qstats.drops++;
+ }
return ret;
}
@@ -430,8 +432,10 @@ cbq_requeue(struct sk_buff *skb, struct Qdisc *sch)
cbq_activate_class(cl);
return 0;
}
- sch->qstats.drops++;
- cl->qstats.drops++;
+ if (net_xmit_drop_count(ret)) {
+ sch->qstats.drops++;
+ cl->qstats.drops++;
+ }
return ret;
}
diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index a935676..7170275 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -236,7 +236,7 @@ static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
kfree_skb(skb);
- return NET_XMIT_SUCCESS;
+ return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
goto drop;
@@ -254,7 +254,8 @@ static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
err = qdisc_enqueue(skb, p->q);
if (err != NET_XMIT_SUCCESS) {
- sch->qstats.drops++;
+ if (net_xmit_drop_count(err))
+ sch->qstats.drops++;
return err;
}
@@ -321,7 +322,8 @@ static int dsmark_requeue(struct sk_buff *skb, struct Qdisc *sch)
err = p->q->ops->requeue(skb, p->q);
if (err != NET_XMIT_SUCCESS) {
- sch->qstats.drops++;
+ if (net_xmit_drop_count(err))
+ sch->qstats.drops++;
return err;
}
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 0ae7d19..5cf9ae7 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1166,7 +1166,7 @@ hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
switch (result) {
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
- *qerr = NET_XMIT_SUCCESS;
+ *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return NULL;
}
@@ -1586,8 +1586,10 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
err = qdisc_enqueue(skb, cl->qdisc);
if (unlikely(err != NET_XMIT_SUCCESS)) {
- cl->qstats.drops++;
- sch->qstats.drops++;
+ if (net_xmit_drop_count(err)) {
+ cl->qstats.drops++;
+ sch->qstats.drops++;
+ }
return err;
}
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 75a4095..635e8ce 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -221,7 +221,7 @@ static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
switch (result) {
case TC_ACT_QUEUED:
case TC_ACT_STOLEN:
- *qerr = NET_XMIT_SUCCESS;
+ *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return NULL;
}
diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index f849243..adb1a52 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -45,7 +45,7 @@ prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
switch (err) {
case TC_ACT_STOLEN:
case TC_ACT_QUEUED:
- *qerr = NET_XMIT_SUCCESS;
+ *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return NULL;
}
@@ -88,7 +88,8 @@ prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
sch->q.qlen++;
return NET_XMIT_SUCCESS;
}
- sch->qstats.drops++;
+ if (net_xmit_drop_count(ret))
+ sch->qstats.drops++;
return ret;
}
@@ -114,7 +115,8 @@ prio_requeue(struct sk_buff *skb, struct Qdisc* sch)
sch->qstats.requeues++;
return 0;
}
- sch->qstats.drops++;
+ if (net_xmit_drop_count(ret))
+ sch->qstats.drops++;
return NET_XMIT_DROP;
}
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index 8589da6..3a456e1 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -178,7 +178,7 @@ static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
switch (result) {
case TC_ACT_STOLEN:
case TC_ACT_QUEUED:
- *qerr = NET_XMIT_SUCCESS;
+ *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
case TC_ACT_SHOT:
return 0;
}
--
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