From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Durrant Subject: [PATCH net v3 2/2] xen-netback: napi: don't prematurely request a tx event Date: Tue, 10 Dec 2013 13:39:42 +0000 Message-ID: <1386682782-7052-3-git-send-email-paul.durrant@citrix.com> References: <1386682782-7052-1-git-send-email-paul.durrant@citrix.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Paul Durrant , Wei Liu , Ian Campbell , David Vrabel To: , Return-path: Received: from smtp02.citrix.com ([66.165.176.63]:27072 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753242Ab3LJNjt (ORCPT ); Tue, 10 Dec 2013 08:39:49 -0500 In-Reply-To: <1386682782-7052-1-git-send-email-paul.durrant@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: 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 Cc: Wei Liu Cc: Ian Campbell Cc: David Vrabel --- 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; -- 1.7.10.4