From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pankaj Gupta Subject: [PATCH v5 net-next 2/2] tuntap: Increase the number of queues in tun. Date: Mon, 12 Jan 2015 11:41:29 +0530 Message-ID: <1421043089-30103-3-git-send-email-pagupta@redhat.com> References: <1421043089-30103-1-git-send-email-pagupta@redhat.com> 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, jiri@resnulli.us, sergei.shtylyov@cogentembedded.com, Pankaj Gupta To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Return-path: In-Reply-To: <1421043089-30103-1-git-send-email-pagupta@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: 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 patch: 'net: allow large number of rx queues' 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. Size of tun_struct changes from 8512 to 10496 after this patch. This keeps pages allocated for tun_struct before and after the patch to 3. Signed-off-by: Pankaj Gupta Reviewed-by: David Gibson --- drivers/net/tun.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index e3fa65a..a3f13f7 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -113,10 +113,9 @@ 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. */ +#define MAX_TAP_QUEUES 256 #define MAX_TAP_FLOWS 4096 #define TUN_FLOW_EXPIRE (3 * HZ) -- 1.8.3.1