On Wed, Dec 03, 2014 at 12:49:37PM +0530, Pankaj Gupta 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 patche: 'net: allow large number of rx queues'
s/patche/patch/
> 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 <pagu...@redhat.com>
> Reviewed-by: David Gibson <dgib...@redhat.com>
Hmm it's kind of nasty that each tun device is now using x16 memory.
Maybe we should look at using a flex array instead, and removing the
limitation altogether (e.g. make it INT_MAX)?
> ---
> 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 e3fa65a..a19dc5f8 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -113,10 +113,11 @@ 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.
It's not queue memory allocation anymore, is it?
I would say "
This also helps the tfiles field fit in 4K, so the whole tun
device only needs an order-1 allocation.
"
> + */
> +#define MAX_TAP_QUEUES 256
> #define MAX_TAP_FLOWS 4096
>
> #define TUN_FLOW_EXPIRE (3 * HZ)
> --
> 1.8.3.1
>
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