linux-toradex.git/include/net/sch_generic.h, branch v2.6.37.2

net_sched: always clone skbs

2010-12-20T18:27:19+00:00

Pawel reported a panic related to handling shared skbs in ixgbe
incorrectly. So we need to revert my previous patch to work around
this bug. Instead of reverting the patch completely, I just revert
the essential lines, so we can add the previous optimization
back more easily in future.

    commit 3511c9132f8b1e1b5634e41a3331c44b0c13be70
    Author: Changli Gao 
    Date:   Sat Oct 16 13:04:08 2010 +0000

        net_sched: remove the unused parameter of qdisc_create_dflt()

Reported-by: Pawel Staszewski 
Signed-off-by: Changli Gao 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

net_sched: remove the unused parameter of qdisc_create_dflt()

2010-10-21T10:09:47+00:00

The first parameter dev isn't in use in qdisc_create_dflt().

Signed-off-by: Changli Gao 
Acked-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller

net: return operator cleanup

2010-09-23T21:33:39+00:00

Change "return (EXPR);" to "return EXPR;"

return is not a function, parentheses are not required.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6

2010-07-07T22:59:38+00:00

net: decreasing real_num_tx_queues needs to flush qdisc

2010-07-03T04:59:07+00:00

Reducing real_num_queues needs to flush the qdisc otherwise
skbs with queue_mappings greater then real_num_tx_queues can
be sent to the underlying driver.

The flow for this is,

dev_queue_xmit()
	dev_pick_tx()
		skb_tx_hash()  => hash using real_num_tx_queues
		skb_set_queue_mapping()
	...
	qdisc_enqueue_root() => enqueue skb on txq from hash
...
dev->real_num_tx_queues -= n
...
sch_direct_xmit()
	dev_hard_start_xmit()
		ndo_start_xmit(skb,dev) => skb queue set with old hash

skbs are enqueued on the qdisc with skb->queue_mapping set
0 < queue_mappings < real_num_tx_queues.  When the driver
decreases real_num_tx_queues skb's may be dequeued from the
qdisc with a queue_mapping greater then real_num_tx_queues.

This fixes a case in ixgbe where this was occurring with DCB
and FCoE. Because the driver is using queue_mapping to map
skbs to tx descriptor rings we can potentially map skbs to
rings that no longer exist.

Signed-off-by: John Fastabend 
Tested-by: Ross Brattain 
Signed-off-by: Jeff Kirsher 
Signed-off-by: David S. Miller

sched: qdisc_reset_all_tx is calling qdisc_reset without qdisc_lock

2010-07-03T04:59:07+00:00

When calling qdisc_reset() the qdisc lock needs to be held.  In
this case there is at least one driver i4l which is using this
without holding the lock.  Add the locking here.

Signed-off-by: John Fastabend 
Signed-off-by: Jeff Kirsher 
Signed-off-by: David S. Miller

act_mirred: don't clone skb when skb isn't shared

2010-06-29T06:24:32+00:00

don't clone skb when skb isn't shared

When the tcf_action is TC_ACT_STOLEN, and the skb isn't shared, we don't need
to clone a new skb. As the skb will be freed after this function returns, we
can use it freely once we get a reference to it.

Signed-off-by: Changli Gao 
----
 include/net/sch_generic.h |   11 +++++++++--
 net/sched/act_mirred.c    |    6 +++---
 2 files changed, 12 insertions(+), 5 deletions(-)
Signed-off-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller

net: add additional lock to qdisc to increase throughput

2010-06-02T12:09:29+00:00

When many cpus compete for sending frames on a given qdisc, the qdisc
spinlock suffers from very high contention.

The cpu owning __QDISC_STATE_RUNNING bit has same priority to acquire
the lock, and cannot dequeue packets fast enough, since it must wait for
this lock for each dequeued packet.

One solution to this problem is to force all cpus spinning on a second
lock before trying to get the main lock, when/if they see
__QDISC_STATE_RUNNING already set.

The owning cpu then compete with at most one other cpu for the main
lock, allowing for higher dequeueing rate.

Based on a previous patch from Alexander Duyck. I added the heuristic to
avoid the atomic in fast path, and put the new lock far away from the
cache line used by the dequeue worker. Also try to release the busylock
lock as late as possible.

Tests with following script gave a boost from ~50.000 pps to ~600.000
pps on a dual quad core machine (E5450 @3.00GHz), tg3 driver.
(A single netperf flow can reach ~800.000 pps on this platform)

for j in `seq 0 3`; do
  for i in `seq 0 7`; do
    netperf -H 192.168.0.1 -t UDP_STREAM -l 60 -N -T $i -- -m 6 &
  done
done

Signed-off-by: Eric Dumazet 
Acked-by: Alexander Duyck 
Signed-off-by: David S. Miller

net: QDISC_STATE_RUNNING dont need atomic bit ops

2010-06-02T10:24:13+00:00

__QDISC_STATE_RUNNING is always changed while qdisc lock is held.

We can avoid two atomic operations in xmit path, if we move this bit in
a new __state container.

Location of this __state container is carefully chosen so that fast path
only dirties one qdisc cache line.

THROTTLED bit could later be moved into this __state location too, to
avoid dirtying first qdisc cache line.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: Define accessors to manipulate QDISC_STATE_RUNNING

2010-06-02T10:23:51+00:00

Define three helpers to manipulate QDISC_STATE_RUNNIG flag, that a
second patch will move on another location.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller