| Message ID | 20211208140702.642741-9-alexandr.lobakin@intel.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: intel: napi_alloc_skb() vs metadata | expand |
>-----Original Message----- >From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of >Alexander Lobakin >Sent: Wednesday, December 8, 2021 7:37 PM >To: intel-wired-lan@lists.osuosl.org >Cc: Song Liu <songliubraving@fb.com>; Jesper Dangaard Brouer ><hawk@kernel.org>; Daniel Borkmann <daniel@iogearbox.net>; Yonghong >Song <yhs@fb.com>; Martin KaFai Lau <kafai@fb.com>; John Fastabend ><john.fastabend@gmail.com>; Alexei Starovoitov <ast@kernel.org>; Andrii >Nakryiko <andrii@kernel.org>; Björn Töpel <bjorn@kernel.org>; >netdev@vger.kernel.org; Jakub Kicinski <kuba@kernel.org>; KP Singh ><kpsingh@kernel.org>; bpf@vger.kernel.org; David S. Miller ><davem@davemloft.net>; linux-kernel@vger.kernel.org >Subject: [Intel-wired-lan] [PATCH v4 net-next 8/9] ixgbe: don't reserve >excessive XDP_PACKET_HEADROOM on XSK Rx to skb > >{__,}napi_alloc_skb() allocates and reserves additional NET_SKB_PAD >+ NET_IP_ALIGN for any skb. >OTOH, ixgbe_construct_skb_zc() currently allocates and reserves additional >`xdp->data - xdp->data_hard_start`, which is XDP_PACKET_HEADROOM for >XSK frames. >There's no need for that at all as the frame is post-XDP and will go only to the >networking stack core. >Pass the size of the actual data only to __napi_alloc_skb() and don't reserve >anything. This will give enough headroom for stack processing. > >Fixes: d0bcacd0a130 ("ixgbe: add AF_XDP zero-copy Rx support") >Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com> >Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com> >--- > drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > Tested-by: Sandeep Penigalapati <sandeep.penigalapati@intel.com>
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c index 1d74a7980d81..db20dc4c2488 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c @@ -214,13 +214,11 @@ static struct sk_buff *ixgbe_construct_skb_zc(struct ixgbe_ring *rx_ring, struct sk_buff *skb; /* allocate a skb to store the frags */ - skb = __napi_alloc_skb(&rx_ring->q_vector->napi, - xdp->data_end - xdp->data_hard_start, + skb = __napi_alloc_skb(&rx_ring->q_vector->napi, datasize, GFP_ATOMIC | __GFP_NOWARN); if (unlikely(!skb)) return NULL; - skb_reserve(skb, xdp->data - xdp->data_hard_start); memcpy(__skb_put(skb, datasize), xdp->data, datasize); if (metasize) skb_metadata_set(skb, metasize);
{__,}napi_alloc_skb() allocates and reserves additional NET_SKB_PAD + NET_IP_ALIGN for any skb. OTOH, ixgbe_construct_skb_zc() currently allocates and reserves additional `xdp->data - xdp->data_hard_start`, which is XDP_PACKET_HEADROOM for XSK frames. There's no need for that at all as the frame is post-XDP and will go only to the networking stack core. Pass the size of the actual data only to __napi_alloc_skb() and don't reserve anything. This will give enough headroom for stack processing. Fixes: d0bcacd0a130 ("ixgbe: add AF_XDP zero-copy Rx support") Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com> Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com> --- drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)