From patchwork Mon Aug 18 13:37:20 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pankaj Gupta X-Patchwork-Id: 381011 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 287F71400D2 for ; Mon, 18 Aug 2014 23:39:21 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751912AbaHRNi7 (ORCPT ); Mon, 18 Aug 2014 09:38:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:8485 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751743AbaHRNi6 (ORCPT ); Mon, 18 Aug 2014 09:38:58 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s7IDcjBe031983 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 18 Aug 2014 09:38:46 -0400 Received: from dhcp223-82.pnq.redhat.com ([10.65.223.17]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s7IDbNmA011293 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 18 Aug 2014 09:38:38 -0400 From: Pankaj Gupta To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: davem@davemloft.net, jasowang@redhat.com, mst@redhat.com, dgibson@redhat.com, vfalico@gmail.com, edumazet@google.com, vyasevic@redhat.com, hkchu@google.com, wuzhy@linux.vnet.ibm.com, xemul@parallels.com, therbert@google.com, bhutchings@solarflare.com, xii@google.com, stephen@networkplumber.org, Pankaj Gupta Subject: [RFC 4/4] tuntap: Increase the number of queues in tun Date: Mon, 18 Aug 2014 19:07:20 +0530 Message-Id: <1408369040-1216-5-git-send-email-pagupta@redhat.com> In-Reply-To: <1408369040-1216-1-git-send-email-pagupta@redhat.com> References: <1408369040-1216-1-git-send-email-pagupta@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Networking under kvm works best if we allocate a per-vCPU RX and TX queue in a virtual NIC. This requires a per-vCPU queue on the host side. It is now safe to increase the maximum number of queues. Preceding patches: net: allow large number of rx queues tuntap: Reduce the size of tun_struct by using flex array tuntap: Publish tuntap max queue length as module_param made sure this won't cause failures due to high order memory allocations. Increase it to 256: this is the max number of vCPUs KVM supports. Signed-off-by: Pankaj Gupta Reviewed-by: David Gibson --- drivers/net/tun.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 98bad1f..893eba8 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -111,10 +111,11 @@ struct tap_filter { unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; }; -/* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for - * the netdevice to be fit in one page. So we can make sure the success of - * memory allocation. TODO: increase the limit. */ -#define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES +/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal + * to max number of vCPUS in guest. Also, we are making sure here + * queue memory allocation do not fail. + */ +#define MAX_TAP_QUEUES 256 #define MAX_TAP_FLOWS 4096 #define TUN_FLOW_EXPIRE (3 * HZ)