From: Pankaj Gupta <pagupta@redhat•com>
To: linux-kernel@vger•kernel.org, netdev@vger•kernel.org
Cc: davem@davemloft•net, jasowang@redhat•com, dgibson@redhat•com,
vfalico@gmail•com, edumazet@google•com, vyasevic@redhat•com,
hkchu@google•com, xemul@parallels•com, therbert@google•com,
bhutchings@solarflare•com, xii@google•com,
stephen@networkplumber•org, jiri@resnulli•us,
sergei shtylyov <sergei.shtylyov@cogentembedded•com>,
"Michael S. Tsirkin" <mst@redhat•com>
Subject: Re: [PATCH v2 net-next 3/3] tuntap: Increase the number of queues in tun.
Date: Mon, 24 Nov 2014 13:46:50 -0500 (EST) [thread overview]
Message-ID: <820095131.3326406.1416854810207.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <1416854050-10165-1-git-send-email-pagupta@redhat.com>
Adding Michael to CC.
>
> 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
>
> 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>
> ---
> 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.
> + */
> +#define MAX_TAP_QUEUES 256
> #define MAX_TAP_FLOWS 4096
>
> #define TUN_FLOW_EXPIRE (3 * HZ)
> --
> 1.8.3.1
>
>
prev parent reply other threads:[~2014-11-24 18:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-24 18:34 [PATCH v2 net-next 3/3] tuntap: Increase the number of queues in tun Pankaj Gupta
2014-11-24 18:46 ` Pankaj Gupta [this message]
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