Tue, Jun 18, 2024 at 08:18:12PM CEST, mst@xxxxxxxxxx wrote:
>This looks like a sensible way to do this.
>Yet something to improve:
>
>
>On Tue, Jun 18, 2024 at 04:44:56PM +0200, Jiri Pirko wrote:
>> From: Jiri Pirko <jiri@xxxxxxxxxx>
>>
[...]
>> +static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
>> + bool in_napi, struct virtnet_sq_free_stats *stats)
>> {
>> unsigned int len;
>> void *ptr;
>>
>> while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
>> - ++stats->packets;
>> -
>> if (!is_xdp_frame(ptr)) {
>> - struct sk_buff *skb = ptr;
>> + struct sk_buff *skb = ptr_to_skb(ptr);
>>
>> pr_debug("Sent skb %p\n", skb);
>>
>> - stats->bytes += skb->len;
>> + if (is_orphan_skb(ptr)) {
>> + stats->packets++;
>> + stats->bytes += skb->len;
>> + } else {
>> + stats->napi_packets++;
>> + stats->napi_bytes += skb->len;
>> + }
>> napi_consume_skb(skb, in_napi);
>> } else {
>> struct xdp_frame *frame = ptr_to_xdp(ptr);
>>
>> + stats->packets++;
>> stats->bytes += xdp_get_frame_len(frame);
>> xdp_return_frame(frame);
>> }
>> }
>> + netdev_tx_completed_queue(txq, stats->napi_packets, stats->napi_bytes);
>
>Are you sure it's right? You are completing larger and larger
>number of bytes and packets each time.
Not sure I get you. __free_old_xmit() is always called with stats
zeroed. So this is just sum-up of one queue completion run.
I don't see how this could become "larger and larger number" as you
describe.
>
>For example as won't this eventually trigger this inside dql_completed:
>
> BUG_ON(count > num_queued - dql->num_completed);
Nope, I don't see how we can hit it. Do not complete anything else
in addition to what was started in xmit(). Am I missing something?
>
>?
>
>
>If I am right the perf testing has to be redone with this fixed ...
>
>
>> }
>>
[...]
