* Re: [Xen-devel] [PATCH net-next] xen-netfront: always set num queues if possible
2015-09-15 10:59 ` [Xen-devel] " David Vrabel
@ 2015-09-15 14:37 ` Charles (Chas) Williams
2015-09-15 14:37 ` Charles (Chas) Williams
` (2 subsequent siblings)
3 siblings, 0 replies; 9+ messages in thread
From: Charles (Chas) Williams @ 2015-09-15 14:37 UTC (permalink / raw)
To: David Vrabel; +Cc: netdev, xen-devel
On Tue, 2015-09-15 at 11:59 +0100, David Vrabel wrote:
> On 14/09/15 22:28, Charles (Chas) Williams wrote:
> > The xen store preserves this information across module invocations.
> > If you insmod netfront with two queues and later insmod again with one
> > queue, the backend will still believe you asked for two queues.
>
> Can you rewrite the commit message to be clearer?
>
> "If netfront connects with 2 (or more) queues and then reconnects with
> only 1 queue it fails to delete or rewrite the multi-queue-num-queues
> key and netback will try to use the wrong number of queues.
>
> Always write the num-queues field if the backend has multi-queue support."
Yes I can do that.
>
> > --- a/drivers/net/xen-netfront.c
> > +++ b/drivers/net/xen-netfront.c
> > @@ -1819,11 +1819,7 @@ again:
> > goto destroy_ring;
> > }
> >
> > - if (num_queues == 1) {
> > - err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
> > - if (err)
> > - goto abort_transaction_no_dev_fatal;
> > - } else {
> > + if (xenbus_exists(xbt, dev->nodename, "multi-queue-num-queues")) {
> > /* Write the number of queues */
> > err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues",
> > "%u", num_queues);
>
> Isn't this broken? It looks like it won't write the
> multi-queue-num-queues key the first time around.
>
> It think this should be conditional on multi-queue-max-queues existing
> (which is written by the backend if multi-queue is supported).
You are right. I am testing against the wrong key here. I should have
tested for multi-queue-max-queues.
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH net-next] xen-netfront: always set num queues if possible
2015-09-15 10:59 ` [Xen-devel] " David Vrabel
2015-09-15 14:37 ` Charles (Chas) Williams
@ 2015-09-15 14:37 ` Charles (Chas) Williams
2015-09-16 20:28 ` [PATCH net-next v2] " Charles (Chas) Williams
2015-09-16 20:28 ` Charles (Chas) Williams
3 siblings, 0 replies; 9+ messages in thread
From: Charles (Chas) Williams @ 2015-09-15 14:37 UTC (permalink / raw)
To: David Vrabel; +Cc: netdev, xen-devel
On Tue, 2015-09-15 at 11:59 +0100, David Vrabel wrote:
> On 14/09/15 22:28, Charles (Chas) Williams wrote:
> > The xen store preserves this information across module invocations.
> > If you insmod netfront with two queues and later insmod again with one
> > queue, the backend will still believe you asked for two queues.
>
> Can you rewrite the commit message to be clearer?
>
> "If netfront connects with 2 (or more) queues and then reconnects with
> only 1 queue it fails to delete or rewrite the multi-queue-num-queues
> key and netback will try to use the wrong number of queues.
>
> Always write the num-queues field if the backend has multi-queue support."
Yes I can do that.
>
> > --- a/drivers/net/xen-netfront.c
> > +++ b/drivers/net/xen-netfront.c
> > @@ -1819,11 +1819,7 @@ again:
> > goto destroy_ring;
> > }
> >
> > - if (num_queues == 1) {
> > - err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
> > - if (err)
> > - goto abort_transaction_no_dev_fatal;
> > - } else {
> > + if (xenbus_exists(xbt, dev->nodename, "multi-queue-num-queues")) {
> > /* Write the number of queues */
> > err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues",
> > "%u", num_queues);
>
> Isn't this broken? It looks like it won't write the
> multi-queue-num-queues key the first time around.
>
> It think this should be conditional on multi-queue-max-queues existing
> (which is written by the backend if multi-queue is supported).
You are right. I am testing against the wrong key here. I should have
tested for multi-queue-max-queues.
^ permalink raw reply [flat|nested] 9+ messages in thread* [PATCH net-next v2] xen-netfront: always set num queues if possible
2015-09-15 10:59 ` [Xen-devel] " David Vrabel
2015-09-15 14:37 ` Charles (Chas) Williams
2015-09-15 14:37 ` Charles (Chas) Williams
@ 2015-09-16 20:28 ` Charles (Chas) Williams
2015-09-16 20:28 ` Charles (Chas) Williams
3 siblings, 0 replies; 9+ messages in thread
From: Charles (Chas) Williams @ 2015-09-16 20:28 UTC (permalink / raw)
To: David Vrabel; +Cc: netdev, xen-devel
If netfront connects with two (or more) queues and then reconnects with
only one queue it fails to delete or rewrite the multi-queue-num-queues
key and netback will try to use the wrong number of queues.
Always write the num-queues field if the backend has multi-queue support.
Signed-off-by: Chas Williams <3chas3@gmail.com>
---
drivers/net/xen-netfront.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index f821a97..9bf63c2 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1819,19 +1819,22 @@ again:
goto destroy_ring;
}
- if (num_queues == 1) {
- err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
- if (err)
- goto abort_transaction_no_dev_fatal;
- } else {
+ if (xenbus_exists(XBT_NIL,
+ info->xbdev->otherend, "multi-queue-max-queues")) {
/* Write the number of queues */
- err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues",
- "%u", num_queues);
+ err = xenbus_printf(xbt, dev->nodename,
+ "multi-queue-num-queues", "%u", num_queues);
if (err) {
message = "writing multi-queue-num-queues";
goto abort_transaction_no_dev_fatal;
}
+ }
+ if (num_queues == 1) {
+ err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
+ if (err)
+ goto abort_transaction_no_dev_fatal;
+ } else {
/* Write the keys for each queue */
for (i = 0; i < num_queues; ++i) {
queue = &info->queues[i];
--
2.1.0
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH net-next v2] xen-netfront: always set num queues if possible
2015-09-15 10:59 ` [Xen-devel] " David Vrabel
` (2 preceding siblings ...)
2015-09-16 20:28 ` [PATCH net-next v2] " Charles (Chas) Williams
@ 2015-09-16 20:28 ` Charles (Chas) Williams
2015-09-21 4:39 ` David Miller
2015-09-21 4:39 ` David Miller
3 siblings, 2 replies; 9+ messages in thread
From: Charles (Chas) Williams @ 2015-09-16 20:28 UTC (permalink / raw)
To: David Vrabel; +Cc: netdev, xen-devel
If netfront connects with two (or more) queues and then reconnects with
only one queue it fails to delete or rewrite the multi-queue-num-queues
key and netback will try to use the wrong number of queues.
Always write the num-queues field if the backend has multi-queue support.
Signed-off-by: Chas Williams <3chas3@gmail.com>
---
drivers/net/xen-netfront.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index f821a97..9bf63c2 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1819,19 +1819,22 @@ again:
goto destroy_ring;
}
- if (num_queues == 1) {
- err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
- if (err)
- goto abort_transaction_no_dev_fatal;
- } else {
+ if (xenbus_exists(XBT_NIL,
+ info->xbdev->otherend, "multi-queue-max-queues")) {
/* Write the number of queues */
- err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues",
- "%u", num_queues);
+ err = xenbus_printf(xbt, dev->nodename,
+ "multi-queue-num-queues", "%u", num_queues);
if (err) {
message = "writing multi-queue-num-queues";
goto abort_transaction_no_dev_fatal;
}
+ }
+ if (num_queues == 1) {
+ err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
+ if (err)
+ goto abort_transaction_no_dev_fatal;
+ } else {
/* Write the keys for each queue */
for (i = 0; i < num_queues; ++i) {
queue = &info->queues[i];
--
2.1.0
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH net-next v2] xen-netfront: always set num queues if possible
2015-09-16 20:28 ` Charles (Chas) Williams
@ 2015-09-21 4:39 ` David Miller
2015-09-21 4:39 ` David Miller
1 sibling, 0 replies; 9+ messages in thread
From: David Miller @ 2015-09-21 4:39 UTC (permalink / raw)
To: 3chas3; +Cc: netdev, david.vrabel, xen-devel
From: "Charles (Chas) Williams" <3chas3@gmail.com>
Date: Wed, 16 Sep 2015 16:28:25 -0400
> If netfront connects with two (or more) queues and then reconnects with
> only one queue it fails to delete or rewrite the multi-queue-num-queues
> key and netback will try to use the wrong number of queues.
>
> Always write the num-queues field if the backend has multi-queue support.
>
> Signed-off-by: Chas Williams <3chas3@gmail.com>
Applied, thanks Chas.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH net-next v2] xen-netfront: always set num queues if possible
2015-09-16 20:28 ` Charles (Chas) Williams
2015-09-21 4:39 ` David Miller
@ 2015-09-21 4:39 ` David Miller
1 sibling, 0 replies; 9+ messages in thread
From: David Miller @ 2015-09-21 4:39 UTC (permalink / raw)
To: 3chas3; +Cc: david.vrabel, netdev, xen-devel
From: "Charles (Chas) Williams" <3chas3@gmail.com>
Date: Wed, 16 Sep 2015 16:28:25 -0400
> If netfront connects with two (or more) queues and then reconnects with
> only one queue it fails to delete or rewrite the multi-queue-num-queues
> key and netback will try to use the wrong number of queues.
>
> Always write the num-queues field if the backend has multi-queue support.
>
> Signed-off-by: Chas Williams <3chas3@gmail.com>
Applied, thanks Chas.
^ permalink raw reply [flat|nested] 9+ messages in thread