Commit f07d1501 authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

multiq: Further multiqueue cleanup



This patch resolves a few issues found with multiq including wording
suggestions and a problem seen in the allocation of queues.
Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 67333bb5
......@@ -29,15 +29,15 @@ Section 2: Qdisc support for multiqueue devices
-----------------------------------------------
Currently two qdiscs support multiqueue devices. The first is the default
pfifo_fast qdisc. This qdisc supports one qdisc per hardware queue. A new
round-robin qdisc, sch_multiq also supports multiple hardware queues. The
Currently two qdiscs are optimized for multiqueue devices. The first is the
default pfifo_fast qdisc. This qdisc supports one qdisc per hardware queue.
A new round-robin qdisc, sch_multiq also supports multiple hardware queues. The
qdisc is responsible for classifying the skb's and then directing the skb's to
bands and queues based on the value in skb->queue_mapping. Use this field in
the base driver to determine which queue to send the skb to.
sch_multiq has been added for hardware that wishes to avoid unnecessary
requeuing. It will cycle though the bands and verify that the hardware queue
sch_multiq has been added for hardware that wishes to avoid head-of-line
blocking. It will cycle though the bands and verify that the hardware queue
associated with the band is not stopped prior to dequeuing a packet.
On qdisc load, the number of bands is based on the number of queues on the
......@@ -63,8 +63,8 @@ band 1 => queue 1
band 2 => queue 2
band 3 => queue 3
Traffic will begin flowing through each queue if your base device has either
the default simple_tx_hash or a custom netdev->select_queue() defined.
Traffic will begin flowing through each queue based on either the simple_tx_hash
function or based on netdev->select_queue() if you have it defined.
The behavior of tc filters remains the same. However a new tc action,
skbedit, has been added. Assuming you wanted to route all traffic to a
......
......@@ -214,8 +214,8 @@ static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
sch_tree_lock(sch);
q->bands = qopt->bands;
for (i = q->bands; i < q->max_bands; i++) {
struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
if (child != &noop_qdisc) {
if (q->queues[i] != &noop_qdisc) {
struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
qdisc_tree_decrease_qlen(child, child->q.qlen);
qdisc_destroy(child);
}
......@@ -250,7 +250,7 @@ static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
{
struct multiq_sched_data *q = qdisc_priv(sch);
int i;
int i, err;
q->queues = NULL;
......@@ -265,7 +265,12 @@ static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
for (i = 0; i < q->max_bands; i++)
q->queues[i] = &noop_qdisc;
return multiq_tune(sch, opt);
err = multiq_tune(sch,opt);
if (err)
kfree(q->queues);
return err;
}
static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
......
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