| Message ID | 1408369040-1216-5-git-send-email-pagupta@redhat.com |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mon, 18 Aug 2014 19:07:20 +0530 Pankaj Gupta <pagupta@redhat.com> wrote: > 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 <pagupta@redhat.com> Reviewed-by: David Gibson <dgibson@redhat.com>
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)
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 <pagupta@redhat.com> --- drivers/net/tun.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)