From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751193AbdFBOyg (ORCPT ); Fri, 2 Jun 2017 10:54:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49064 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751141AbdFBOyf (ORCPT ); Fri, 2 Jun 2017 10:54:35 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com EBD3120B19 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=mst@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com EBD3120B19 Date: Fri, 2 Jun 2017 17:54:33 +0300 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org, David Miller Cc: Mikulas Patocka , "J. Bruce Fields" , Jason Wang , virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Subject: [PATCH v2] virtio_net: lower limit on buffer size Message-ID: <1496415192-17031-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mutt-Fcc: =sent X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Fri, 02 Jun 2017 14:54:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit d85b758f72b0 ("virtio_net: fix support for small rings") was supposed to increase the buffer size for small rings but had an unintentional side effect of decreasing it for large rings. This seems to break some setups - it's not yet clear why, but increasing buffer size back to what it was before helps. Fixes: d85b758f72b0 ("virtio_net: fix support for small rings") Reported-by: Mikulas Patocka Reported-by: "J. Bruce Fields" Tested-by: Mikulas Patocka Tested-by: "J. Bruce Fields" Signed-off-by: Michael S. Tsirkin --- Patch tested, pls merge. changes from v2: commit log tweaks to address comments by Sergei Shtylyov drivers/net/virtio_net.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 87b5c20..60abb5d 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -842,7 +842,7 @@ static unsigned int get_mergeable_buf_len(struct receive_queue *rq, unsigned int len; len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len), - rq->min_buf_len - hdr_len, PAGE_SIZE - hdr_len); + rq->min_buf_len, PAGE_SIZE - hdr_len); return ALIGN(len, L1_CACHE_BYTES); } @@ -2039,7 +2039,8 @@ static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct virtqu unsigned int buf_len = hdr_len + ETH_HLEN + VLAN_HLEN + packet_len; unsigned int min_buf_len = DIV_ROUND_UP(buf_len, rq_size); - return max(min_buf_len, hdr_len); + return max(max(min_buf_len, hdr_len) - hdr_len, + (unsigned int)GOOD_PACKET_LEN); } static int virtnet_find_vqs(struct virtnet_info *vi) -- MST