From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [RFC 1/4] net: allow large number of rx queues Date: Mon, 18 Aug 2014 21:43:40 +0400 Message-ID: <53F23B4C.2000507@cogentembedded.com> References: <1408369040-1216-1-git-send-email-pagupta@redhat.com> <1408369040-1216-2-git-send-email-pagupta@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit 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 To: Pankaj Gupta , linux-kernel@vger.kernel.org, netdev@vger.kernel.org Return-path: In-Reply-To: <1408369040-1216-2-git-send-email-pagupta@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hello. On 08/18/2014 05:37 PM, 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 | 20 +++++++++++++------- > 1 file changed, 13 insertions(+), 7 deletions(-) > diff --git a/net/core/dev.c b/net/core/dev.c > index 1c15b18..a455a02 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -5942,17 +5942,24 @@ 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); > +} > + > 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); Please keep an empty line after declarations. > BUG_ON(count < 1); > WBR, Sergei