Message ID | 1426087679-13927-1-git-send-email-david.vrabel@citrix.com |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
On 11/03/15 15:27, David Vrabel wrote: > This fixes a performance regression introduced by > 7fbb9d8415d4a51cf542e87cf3a717a9f7e6aedc (xen-netback: release pending > index before pushing Tx responses) > > Moving the notify outside of the spin locks means it can be delayed a > long time (if the dealloc thread is descheduled or there is an > interrupt or softirq). > > Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Zoltan Kiss <zoltan.kiss@linaro.org> > --- > drivers/net/xen-netback/netback.c | 23 ++++++++++++----------- > 1 file changed, 12 insertions(+), 11 deletions(-) > > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c > index c4d68d7..7f8a466 100644 > --- a/drivers/net/xen-netback/netback.c > +++ b/drivers/net/xen-netback/netback.c > @@ -96,6 +96,7 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, > static void make_tx_response(struct xenvif_queue *queue, > struct xen_netif_tx_request *txp, > s8 st); > +static void push_tx_responses(struct xenvif_queue *queue); > > static inline int tx_work_todo(struct xenvif_queue *queue); > > @@ -655,15 +656,10 @@ static void xenvif_tx_err(struct xenvif_queue *queue, > unsigned long flags; > > do { > - int notify; > - > spin_lock_irqsave(&queue->response_lock, flags); > make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR); > - RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); > + push_tx_responses(queue); > spin_unlock_irqrestore(&queue->response_lock, flags); > - if (notify) > - notify_remote_via_irq(queue->tx_irq); > - > if (cons == end) > break; > txp = RING_GET_REQUEST(&queue->tx, cons++); > @@ -1655,7 +1651,6 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, > { > struct pending_tx_info *pending_tx_info; > pending_ring_idx_t index; > - int notify; > unsigned long flags; > > pending_tx_info = &queue->pending_tx_info[pending_idx]; > @@ -1671,12 +1666,9 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, > index = pending_index(queue->pending_prod++); > queue->pending_ring[index] = pending_idx; > > - RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); > + push_tx_responses(queue); > > spin_unlock_irqrestore(&queue->response_lock, flags); > - > - if (notify) > - notify_remote_via_irq(queue->tx_irq); > } > > > @@ -1697,6 +1689,15 @@ static void make_tx_response(struct xenvif_queue *queue, > queue->tx.rsp_prod_pvt = ++i; > } > > +static void push_tx_responses(struct xenvif_queue *queue) > +{ > + int notify; > + > + RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); > + if (notify) > + notify_remote_via_irq(queue->tx_irq); > +} > + > static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue, > u16 id, > s8 st, > -- 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
On Wed, Mar 11, 2015 at 03:27:59PM +0000, David Vrabel wrote: > This fixes a performance regression introduced by > 7fbb9d8415d4a51cf542e87cf3a717a9f7e6aedc (xen-netback: release pending > index before pushing Tx responses) > > Moving the notify outside of the spin locks means it can be delayed a > long time (if the dealloc thread is descheduled or there is an > interrupt or softirq). > > Signed-off-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> -- 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: Wed, 11 Mar 2015 15:27:59 +0000 > This fixes a performance regression introduced by > 7fbb9d8415d4a51cf542e87cf3a717a9f7e6aedc (xen-netback: release pending > index before pushing Tx responses) > > Moving the notify outside of the spin locks means it can be delayed a > long time (if the dealloc thread is descheduled or there is an > interrupt or softirq). > > Signed-off-by: David Vrabel <david.vrabel@citrix.com> Applied, thanks David. -- 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/netback.c b/drivers/net/xen-netback/netback.c index c4d68d7..7f8a466 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -96,6 +96,7 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, static void make_tx_response(struct xenvif_queue *queue, struct xen_netif_tx_request *txp, s8 st); +static void push_tx_responses(struct xenvif_queue *queue); static inline int tx_work_todo(struct xenvif_queue *queue); @@ -655,15 +656,10 @@ static void xenvif_tx_err(struct xenvif_queue *queue, unsigned long flags; do { - int notify; - spin_lock_irqsave(&queue->response_lock, flags); make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR); - RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); + push_tx_responses(queue); spin_unlock_irqrestore(&queue->response_lock, flags); - if (notify) - notify_remote_via_irq(queue->tx_irq); - if (cons == end) break; txp = RING_GET_REQUEST(&queue->tx, cons++); @@ -1655,7 +1651,6 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, { struct pending_tx_info *pending_tx_info; pending_ring_idx_t index; - int notify; unsigned long flags; pending_tx_info = &queue->pending_tx_info[pending_idx]; @@ -1671,12 +1666,9 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, index = pending_index(queue->pending_prod++); queue->pending_ring[index] = pending_idx; - RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); + push_tx_responses(queue); spin_unlock_irqrestore(&queue->response_lock, flags); - - if (notify) - notify_remote_via_irq(queue->tx_irq); } @@ -1697,6 +1689,15 @@ static void make_tx_response(struct xenvif_queue *queue, queue->tx.rsp_prod_pvt = ++i; } +static void push_tx_responses(struct xenvif_queue *queue) +{ + int notify; + + RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); + if (notify) + notify_remote_via_irq(queue->tx_irq); +} + static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue, u16 id, s8 st,
This fixes a performance regression introduced by 7fbb9d8415d4a51cf542e87cf3a717a9f7e6aedc (xen-netback: release pending index before pushing Tx responses) Moving the notify outside of the spin locks means it can be delayed a long time (if the dealloc thread is descheduled or there is an interrupt or softirq). Signed-off-by: David Vrabel <david.vrabel@citrix.com> --- drivers/net/xen-netback/netback.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)