From: David Vrabel <david.vra...@citrix.com> Date: Fri, 15 Jan 2016 10:31:57 +0000
> On 14/01/16 21:54, David Miller wrote: >> From: David Vrabel <david.vra...@citrix.com> >> Date: Thu, 14 Jan 2016 15:18:30 +0000 >> >>> - needed = xenvif_rx_ring_slots_needed(queue->vif); >>> + skb = skb_peek(&queue->rx_queue); >>> + if (!skb) >>> + return false; >>> + >>> + needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE); >>> + if (skb_is_gso(skb)) >>> + needed++; >> >> If I am not mistaken, we moved away from this kind of test exactly because >> it is inaccurate and may under-estimate the needs. >> >> It is possible for an N byte SKB to require N segments. Therefore, the: >> >> DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE); >> >> calculation doesn't cut it. > > After 1650d5455bd2dc6b5ee134bd6fc1a3236c266b5b (xen-netback: always > fully coalesce guest Rx packets) we always fully pack a packet into its > guest Rx slots. Each slot has space for XEN_PAGE_SIZE bytes so this > calculation for the number of slots is correct. > > Shall I resend with a more description changelog? Yeah that would help a lot. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
