| Message ID | 1386682782-7052-3-git-send-email-paul.durrant@citrix.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Tue, 2013-12-10 at 13:39 +0000, Paul Durrant wrote: > This patch changes the RING_FINAL_CHECK_FOR_REQUESTS in > xenvif_build_tx_gops to a check for RING_HAS_UNCONSUMED_REQUESTS as the > former call has the side effect of advancing the ring event pointer and > therefore inviting another interrupt from the frontend before the napi > poll has actually finished, thereby defeating the point of napi. Like I said last time: Can you add a reminder of when/where the ring event pointer is eventually advanced now please. > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > Cc: Wei Liu <wei.liu2@citrix.com> > Cc: Ian Campbell <ian.campbell@citrix.com> > Cc: David Vrabel <david.vrabel@citrix.com> > --- > drivers/net/xen-netback/netback.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c > index 83b4e5b..fb512a9 100644 > --- a/drivers/net/xen-netback/netback.c > +++ b/drivers/net/xen-netback/netback.c > @@ -1381,7 +1381,7 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget) > continue; > } > > - RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do); > + work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&vif->tx); > if (!work_to_do) > break; > -- 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 83b4e5b..fb512a9 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1381,7 +1381,7 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget) continue; } - RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do); + work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&vif->tx); if (!work_to_do) break;
This patch changes the RING_FINAL_CHECK_FOR_REQUESTS in xenvif_build_tx_gops to a check for RING_HAS_UNCONSUMED_REQUESTS as the former call has the side effect of advancing the ring event pointer and therefore inviting another interrupt from the frontend before the napi poll has actually finished, thereby defeating the point of napi. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> --- drivers/net/xen-netback/netback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)