[PATCH 3/3][STABLE] KVM: add schedule check to napi_enable call

[PATCH 3/3][STABLE] KVM: add schedule check to napi_enable call

[Bruce Rogers]

    virtio_net: Add schedule check to napi_enable call
    Under harsh testing conditions, including low memory, the guest would
    stop receiving packets. With this patch applied we no longer see any
    problems in the driver while performing these tests for extended periods
    of time.

    Make sure napi is scheduled subsequent to each napi_enable.

    Signed-off-by: Bruce Rogers <brogers@novell.com>
    Signed-off-by: Olaf Kirch <okir@suse.de>

--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -388,6 +388,20 @@ static void skb_recv_done(struct virtque
        }
 }

+static void virtnet_napi_enable(struct virtnet_info *vi)
+{
+       napi_enable(&vi->napi);
+
+       /* If all buffers were filled by other side before we napi_enabled, we
+        * won't get another interrupt, so process any outstanding packets
+        * now.  virtnet_poll wants re-enable the queue, so we disable here.
+        * We synchronize against interrupts via NAPI_STATE_SCHED */
+       if (napi_schedule_prep(&vi->napi)) {
+               vi->rvq->vq_ops->disable_cb(vi->rvq);
+               __napi_schedule(&vi->napi);
+       }
+}
+
 static void refill_work(struct work_struct *work)
 {
        struct virtnet_info *vi;
@@ -397,7 +411,7 @@ static void refill_work(struct work_stru
        napi_disable(&vi->napi);
        try_fill_recv(vi, GFP_KERNEL);
        still_empty = (vi->num == 0);
-       napi_enable(&vi->napi);
+       virtnet_napi_enable(vi);

        /* In theory, this can happen: if we don't get any buffers in
         * we will *never* try to fill again. */
@@ -589,16 +603,7 @@ static int virtnet_open(struct net_devic
 {
        struct virtnet_info *vi = netdev_priv(dev);

-       napi_enable(&vi->napi);
-
-       /* If all buffers were filled by other side before we napi_enabled, we
-        * won't get another interrupt, so process any outstanding packets
-        * now.  virtnet_poll wants re-enable the queue, so we disable here.
-        * We synchronize against interrupts via NAPI_STATE_SCHED */
-       if (napi_schedule_prep(&vi->napi)) {
-               vi->rvq->vq_ops->disable_cb(vi->rvq);
-               __napi_schedule(&vi->napi);
-       }
+       virtnet_napi_enable(vi);
        return 0;
 }

Re: [stable] [PATCH 3/3][STABLE] KVM: add schedule check to napi_enable call

[Greg KH]

On Thu, Jun 03, 2010 at 01:38:31PM -0600, Bruce Rogers wrote:
>     virtio_net: Add schedule check to napi_enable call
>     Under harsh testing conditions, including low memory, the guest would
>     stop receiving packets. With this patch applied we no longer see any
>     problems in the driver while performing these tests for extended periods
>     of time.
> 
>     Make sure napi is scheduled subsequent to each napi_enable.
> 
>     Signed-off-by: Bruce Rogers <brogers@novell.com>
>     Signed-off-by: Olaf Kirch <okir@suse.de>

I need a git commit id for this one as well.

thanks,

greg k-h

Re: [stable] [PATCH 3/3][STABLE] KVM: add schedule check to napi_enable call

[Bruce Rogers]

 >>> On 6/3/2010 at 03:03 PM, Greg KH <greg@kroah.com> wrote: 
> On Thu, Jun 03, 2010 at 01:38:31PM -0600, Bruce Rogers wrote:
>>     virtio_net: Add schedule check to napi_enable call
>>     Under harsh testing conditions, including low memory, the guest would
>>     stop receiving packets. With this patch applied we no longer see any
>>     problems in the driver while performing these tests for extended periods
>>     of time.
>> 
>>     Make sure napi is scheduled subsequent to each napi_enable.
>> 
>>     Signed-off-by: Bruce Rogers <brogers@novell.com>
>>     Signed-off-by: Olaf Kirch <okir@suse.de>
> 
> I need a git commit id for this one as well.
> 

This one is not upstream.

Bruce

Re: [stable] [PATCH 3/3][STABLE] KVM: add schedule check to napi_enable call

[Greg KH]

On Thu, Jun 03, 2010 at 04:17:34PM -0600, Bruce Rogers wrote:
>  >>> On 6/3/2010 at 03:03 PM, Greg KH <greg@kroah.com> wrote: 
> > On Thu, Jun 03, 2010 at 01:38:31PM -0600, Bruce Rogers wrote:
> >>     virtio_net: Add schedule check to napi_enable call
> >>     Under harsh testing conditions, including low memory, the guest would
> >>     stop receiving packets. With this patch applied we no longer see any
> >>     problems in the driver while performing these tests for extended periods
> >>     of time.
> >> 
> >>     Make sure napi is scheduled subsequent to each napi_enable.
> >> 
> >>     Signed-off-by: Bruce Rogers <brogers@novell.com>
> >>     Signed-off-by: Olaf Kirch <okir@suse.de>
> > 
> > I need a git commit id for this one as well.
> > 
> 
> This one is not upstream.

Then I can't include it in the -stable tree, so why are you sending it
to me?  :)

thanks,

greg k-h

Re: [stable] [PATCH 3/3][STABLE] KVM: add schedule check to napi_enable call

[Bruce Rogers]

 >>> On 6/3/2010 at 04:51 PM, Greg KH <greg@kroah.com> wrote: 
> On Thu, Jun 03, 2010 at 04:17:34PM -0600, Bruce Rogers wrote:
>>  >>> On 6/3/2010 at 03:03 PM, Greg KH <greg@kroah.com> wrote: 
>> > On Thu, Jun 03, 2010 at 01:38:31PM -0600, Bruce Rogers wrote:
>> >>     virtio_net: Add schedule check to napi_enable call
>> >>     Under harsh testing conditions, including low memory, the guest would
>> >>     stop receiving packets. With this patch applied we no longer see any
>> >>     problems in the driver while performing these tests for extended 
> periods
>> >>     of time.
>> >> 
>> >>     Make sure napi is scheduled subsequent to each napi_enable.
>> >> 
>> >>     Signed-off-by: Bruce Rogers <brogers@novell.com>
>> >>     Signed-off-by: Olaf Kirch <okir@suse.de>
>> > 
>> > I need a git commit id for this one as well.
>> > 
>> 
>> This one is not upstream.
> 
> Then I can't include it in the -stable tree, so why are you sending it
> to me?  :)
> 
> thanks,
> 
> greg k-h

Good point!
Sorry about the confusion.
Bruce

Re: [stable] [PATCH 3/3][STABLE] KVM: add schedule check to napi_enable call

[Bruce Rogers]

 >>> On 6/3/2010 at 04:51 PM, Greg KH <greg@kroah.com> wrote: 
> On Thu, Jun 03, 2010 at 04:17:34PM -0600, Bruce Rogers wrote:
>>  >>> On 6/3/2010 at 03:03 PM, Greg KH <greg@kroah.com> wrote: 
>> > On Thu, Jun 03, 2010 at 01:38:31PM -0600, Bruce Rogers wrote:
>> >>     virtio_net: Add schedule check to napi_enable call
>> >>     Under harsh testing conditions, including low memory, the guest would
>> >>     stop receiving packets. With this patch applied we no longer see any
>> >>     problems in the driver while performing these tests for extended 
> periods
>> >>     of time.
>> >> 
>> >>     Make sure napi is scheduled subsequent to each napi_enable.
>> >> 
>> >>     Signed-off-by: Bruce Rogers <brogers@novell.com>
>> >>     Signed-off-by: Olaf Kirch <okir@suse.de>
>> > 
>> > I need a git commit id for this one as well.
>> > 
>> 
>> This one is not upstream.
> 
> Then I can't include it in the -stable tree, so why are you sending it
> to me?  :)
> 
> thanks,
> 
> greg k-h

Good point!
Sorry about the confusion.
Bruce

Re: [stable] [PATCH 3/3][STABLE] KVM: add schedule check to napi_enable call

[Peter Lieven]

Am 04.06.2010 um 02:02 schrieb Bruce Rogers:

>>>> On 6/3/2010 at 04:51 PM, Greg KH <greg@kroah.com> wrote: 
>> On Thu, Jun 03, 2010 at 04:17:34PM -0600, Bruce Rogers wrote:
>>>>>> On 6/3/2010 at 03:03 PM, Greg KH <greg@kroah.com> wrote: 
>>>> On Thu, Jun 03, 2010 at 01:38:31PM -0600, Bruce Rogers wrote:
>>>>>    virtio_net: Add schedule check to napi_enable call
>>>>>    Under harsh testing conditions, including low memory, the guest would
>>>>>    stop receiving packets. With this patch applied we no longer see any
>>>>>    problems in the driver while performing these tests for extended 
>> periods
>>>>>    of time.
>>>>> 
>>>>>    Make sure napi is scheduled subsequent to each napi_enable.
>>>>> 
>>>>>    Signed-off-by: Bruce Rogers <brogers@novell.com>
>>>>>    Signed-off-by: Olaf Kirch <okir@suse.de>
>>>> 
>>>> I need a git commit id for this one as well.
>>>> 
>>> 
>>> This one is not upstream.
>> 
>> Then I can't include it in the -stable tree, so why are you sending it
>> to me?  :)
>> 
>> thanks,
>> 
>> greg k-h
> 
> Good point!
> Sorry about the confusion.
> Bruce

Is there any reason why this patch is not yet in the stable kernel?
virtio_net is still crashing under heavy load in current vanilla kernel.
This patch *might be* the solution.


> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [stable] [PATCH 3/3][STABLE] KVM: add schedule check to napi_enable call

[Avi Kivity]

On 12/03/2010 05:44 PM, Peter Lieven wrote:
> Is there any reason why this patch is not yet in the stable kernel?
> virtio_net is still crashing under heavy load in current vanilla kernel.
> This patch *might be* the solution.

Perhaps some confusion.  I've asked Greg to take kvm patches from 
Marcelo and myself (after they've been autotested), however virtio is 
not kvm, so the normal stable@ free-for-all applies.

-- 
error compiling committee.c: too many arguments to function