Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932147AbaLDKpO (ORCPT ); Thu, 4 Dec 2014 05:45:14 -0500 Received: from mx5-phx2.redhat.com ([209.132.183.37]:33198 "EHLO mx5-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753302AbaLDKpN (ORCPT ); Thu, 4 Dec 2014 05:45:13 -0500 Date: Thu, 4 Dec 2014 05:45:01 -0500 (EST) From: Pankaj Gupta To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net, jasowang@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, jiri@resnulli.us, sergei shtylyov Message-ID: <1038347703.8637611.1417689901567.JavaMail.zimbra@redhat.com> In-Reply-To: <20141203094224.GB9487@redhat.com> References: <1417591177-7985-1-git-send-email-pagupta@redhat.com> <1417591177-7985-2-git-send-email-pagupta@redhat.com> <20141203094224.GB9487@redhat.com> Subject: Re: [PATCH v3 net-next 1/2] net: allow large number of rx queues MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.5.82.11] X-Mailer: Zimbra 8.0.6_GA_5922 (ZimbraWebClient - FF23 (Linux)/8.0.6_GA_5922) Thread-Topic: allow large number of rx queues Thread-Index: gpK0eqyMU6Yh1dMAgOlqtRoQkuOFBA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > On Wed, Dec 03, 2014 at 12:49:36PM +0530, Pankaj Gupta wrote: > > netif_alloc_rx_queues() uses kcalloc() to allocate memory > > for "struct netdev_queue *_rx" array. > > If we are doing large rx queue allocation kcalloc() might > > fail, so this patch does a fallback to vzalloc(). > > Similar implementation is done for tx queue allocation in > > netif_alloc_netdev_queues(). > > > > We avoid failure of high order memory allocation > > with the help of vzalloc(), this allows us to do large > > rx and tx queue allocation which in turn helps us to > > increase the number of queues in tun. > > > > As vmalloc() adds overhead on a critical network path, > > __GFP_REPEAT flag is used with kzalloc() to do this fallback > > only when really needed. > > > > Signed-off-by: Pankaj Gupta > > Reviewed-by: Michael S. Tsirkin > > Reviewed-by: David Gibson > > --- > > net/core/dev.c | 19 +++++++++++++------ > > 1 file changed, 13 insertions(+), 6 deletions(-) > > > > diff --git a/net/core/dev.c b/net/core/dev.c > > index e916ba8..abe9560 100644 > > --- a/net/core/dev.c > > +++ b/net/core/dev.c > > @@ -6059,17 +6059,25 @@ void netif_stacked_transfer_operstate(const struct > > net_device *rootdev, > > EXPORT_SYMBOL(netif_stacked_transfer_operstate); > > > > #ifdef CONFIG_SYSFS > > +static void netif_free_rx_queues(struct net_device *dev) > > +{ > > + kvfree(dev->_rx); > > +} > > + > > I would just open-code this. I will make the changes with the next version. Thanks, Pankaj > > > static int netif_alloc_rx_queues(struct net_device *dev) > > { > > unsigned int i, count = dev->num_rx_queues; > > struct netdev_rx_queue *rx; > > + size_t sz = count * sizeof(*rx); > > > > BUG_ON(count < 1); > > > > - rx = kcalloc(count, sizeof(struct netdev_rx_queue), GFP_KERNEL); > > - if (!rx) > > - return -ENOMEM; > > - > > + rx = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); > > + if (!rx) { > > + rx = vzalloc(sz); > > + if (!rx) > > + return -ENOMEM; > > + } > > dev->_rx = rx; > > > > for (i = 0; i < count; i++) > > @@ -6698,9 +6706,8 @@ void free_netdev(struct net_device *dev) > > > > netif_free_tx_queues(dev); > > #ifdef CONFIG_SYSFS > > - kfree(dev->_rx); > > + netif_free_rx_queues(dev); > > #endif > > - > > and I think it's nicer with the empty line. > > > kfree(rcu_dereference_protected(dev->ingress_queue, 1)); > > > > /* Flush device addresses */ > > -- > > 1.8.3.1 > > > > -- > > 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 > -- > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/