| Message ID | 20211208140702.642741-5-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 4/9] ice: 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, ice_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: 2d4238f55697 ("ice: Add support for AF_XDP") > Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com> > Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com> > --- > drivers/net/ethernet/intel/ice/ice_xsk.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > Tested-by: Kiran Bhandare <kiranx.bhandare@intel.com> A Contingent Worker at Intel
diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c index f8ea6b0633eb..f0bd8e1953bf 100644 --- a/drivers/net/ethernet/intel/ice/ice_xsk.c +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c @@ -430,15 +430,13 @@ ice_construct_skb_zc(struct ice_rx_ring *rx_ring, struct xdp_buff **xdp_arr) struct xdp_buff *xdp = *xdp_arr; unsigned int metasize = xdp->data - xdp->data_meta; unsigned int datasize = xdp->data_end - xdp->data; - unsigned int datasize_hard = xdp->data_end - xdp->data_hard_start; struct sk_buff *skb; - skb = __napi_alloc_skb(&rx_ring->q_vector->napi, datasize_hard, + 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, ice_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: 2d4238f55697 ("ice: Add support for AF_XDP") Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com> Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com> --- drivers/net/ethernet/intel/ice/ice_xsk.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)