| Message ID | 1422896271-26551-1-git-send-email-david.vrabel@citrix.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mon, Feb 02, 2015 at 04:57:51PM +0000, David Vrabel wrote: > After commit e9d8b2c2968499c1f96563e6522c56958d5a1d0d (xen-netback: > disable rogue vif in kthread context), a fatal (protocol) error would > leave the guest Rx thread spinning, wasting CPU time. Commit > ecf08d2dbb96d5a4b4bcc53a39e8d29cc8fef02e (xen-netback: reintroduce > guest Rx stall detection) made this even worse by removing a > cond_resched() from this path. > > Since a fatal error is non-recoverable, just allow the guest Rx thread > to exit. This requires taking additional refs to the task so the > thread exiting early is handled safely. > > Signed-off-by: David Vrabel <david.vrabel@citrix.com> > Reported-by: Julien Grall <julien.grall@linaro.org> > Tested-by: Julien Grall <julien.grall@linaro.org> Acked-by: Wei Liu <wei.liu2@citrix.com> > --- > drivers/net/xen-netback/interface.c | 2 ++ > drivers/net/xen-netback/netback.c | 3 +-- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c > index 9259a73..037f74f 100644 > --- a/drivers/net/xen-netback/interface.c > +++ b/drivers/net/xen-netback/interface.c > @@ -578,6 +578,7 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref, > goto err_rx_unbind; > } > queue->task = task; > + get_task_struct(task); > > task = kthread_create(xenvif_dealloc_kthread, > (void *)queue, "%s-dealloc", queue->name); > @@ -634,6 +635,7 @@ void xenvif_disconnect(struct xenvif *vif) > > if (queue->task) { > kthread_stop(queue->task); > + put_task_struct(queue->task); > queue->task = NULL; > } > > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c > index 908e65e..c8ce701 100644 > --- a/drivers/net/xen-netback/netback.c > +++ b/drivers/net/xen-netback/netback.c > @@ -2109,8 +2109,7 @@ int xenvif_kthread_guest_rx(void *data) > */ > if (unlikely(vif->disabled && queue->id == 0)) { > xenvif_carrier_off(vif); > - xenvif_rx_queue_purge(queue); > - continue; > + break; > } > > if (!skb_queue_empty(&queue->rx_queue)) > -- > 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: David Vrabel <david.vrabel@citrix.com> Date: Mon, 2 Feb 2015 16:57:51 +0000 > After commit e9d8b2c2968499c1f96563e6522c56958d5a1d0d (xen-netback: > disable rogue vif in kthread context), a fatal (protocol) error would > leave the guest Rx thread spinning, wasting CPU time. Commit > ecf08d2dbb96d5a4b4bcc53a39e8d29cc8fef02e (xen-netback: reintroduce > guest Rx stall detection) made this even worse by removing a > cond_resched() from this path. > > Since a fatal error is non-recoverable, just allow the guest Rx thread > to exit. This requires taking additional refs to the task so the > thread exiting early is handled safely. > > Signed-off-by: David Vrabel <david.vrabel@citrix.com> > Reported-by: Julien Grall <julien.grall@linaro.org> > Tested-by: Julien Grall <julien.grall@linaro.org> Applied, thank you. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 9259a73..037f74f 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -578,6 +578,7 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref, goto err_rx_unbind; } queue->task = task; + get_task_struct(task); task = kthread_create(xenvif_dealloc_kthread, (void *)queue, "%s-dealloc", queue->name); @@ -634,6 +635,7 @@ void xenvif_disconnect(struct xenvif *vif) if (queue->task) { kthread_stop(queue->task); + put_task_struct(queue->task); queue->task = NULL; } diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 908e65e..c8ce701 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -2109,8 +2109,7 @@ int xenvif_kthread_guest_rx(void *data) */ if (unlikely(vif->disabled && queue->id == 0)) { xenvif_carrier_off(vif); - xenvif_rx_queue_purge(queue); - continue; + break; } if (!skb_queue_empty(&queue->rx_queue))