On 6/26/2018 4:04 AM, Willem de Bruijn wrote:
> On Mon, Jun 25, 2018 at 7:06 PM Amritha Nambiar
> <amritha.namb...@intel.com> wrote:
>>
>> This patch adds support to pick Tx queue based on the Rx queue(s) map
>> configuration set by the admin through the sysfs attribute
>> for each Tx queue. If the user configuration for receive queue(s) map
>> does not apply, then the Tx queue selection falls back to CPU(s) map
>> based selection and finally to hashing.
>>
>> Signed-off-by: Amritha Nambiar <amritha.namb...@intel.com>
>> ---
>
>> +static int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
>> {
>> #ifdef CONFIG_XPS
>> struct xps_dev_maps *dev_maps;
>> - struct xps_map *map;
>> + struct sock *sk = skb->sk;
>> int queue_index = -1;
>>
>> if (!static_key_false(&xps_needed))
>> return -1;
>>
>> rcu_read_lock();
>> - dev_maps = rcu_dereference(dev->xps_cpus_map);
>> + if (!static_key_false(&xps_rxqs_needed))
>> + goto get_cpus_map;
>> +
>> + dev_maps = rcu_dereference(dev->xps_rxqs_map);
>> if (dev_maps) {
>> - unsigned int tci = skb->sender_cpu - 1;
>> + int tci = sk_rx_queue_get(sk);
>
> What if the rx device differs from the tx device?
>
I think I have 3 options here:
1. Cache the ifindex in sock_common which will introduce a new
additional field in sock_common.
2. Use dev_get_by_napi_id to get the device id. This could be expensive,
if the rxqs_map is set, this will be done on every packet and involves
walking through the hashlist for napi_id lookup.
3. Remove validating device id, similar to how it is in skb_tx_hash
where rx_queue recorded is used and if not, fall through to flow hash
calculation.
What do you think is suitable here?
