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gve: pull network headers into skb linear part

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Currently, in DQO mode with hw-gro enabled, entire received packet is
placed into skb fragments when header-split is disabled. This leaves
the skb linear part empty, forcing the networking stack to do multiple
small memory copies to access eth, IP and TCP headers.

This patch adds a single memcpy to put all headers into linear portion
before packet reaches the SW GRO stack; thus eliminating multiple
smaller memcpy calls.

Additionally, the criteria for calling napi_gro_frags() was updated.
Since skb->head is now populated, we instead check if the SKB is the
cached NAPI scratchpad to ensure we continue using the zero-allocation
path.

Signed-off-by: Ankit Garg <nktgrg@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Signed-off-by: Joshua Washington <joshwash@google.com>
Link: https://patch.msgid.link/20260303195549.2679070-4-joshwash@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Ankit Garg 2026-03-03 11:55:48 -08:00 committed by Paolo Abeni
parent ea4c117687
commit 0c7025fd24
1 changed files with 16 additions and 4 deletions
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20
drivers/net/ethernet/google/gve/gve_rx_dqo.c
View File

@ -943,6 +943,8 @@ static int gve_rx_complete_rsc(struct sk_buff *skb,
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
int rsc_segments, rsc_seg_len, hdr_len;
skb_frag_t *frag;
void *va;
/* HW-GRO only coalesces TCP. */
if (ptype.l4_type != GVE_L4_TYPE_TCP)
@ -970,10 +972,20 @@ static int gve_rx_complete_rsc(struct sk_buff *skb,
/* HW-GRO packets are guaranteed to have complete TCP/IP
* headers in frag[0] when header-split is not enabled.
*/
hdr_len = eth_get_headlen(skb->dev,
skb_frag_address(&shinfo->frags[0]),
skb_frag_size(&shinfo->frags[0]));
frag = &skb_shinfo(skb)->frags[0];
va = skb_frag_address(frag);
hdr_len =
eth_get_headlen(skb->dev, va, skb_frag_size(frag));
rsc_segments = DIV_ROUND_UP(skb->len - hdr_len, rsc_seg_len);
skb_copy_to_linear_data(skb, va, hdr_len);
skb_frag_size_sub(frag, hdr_len);
/* Verify we didn't empty the fragment completely as that could
* otherwise lead to page leaks.
*/
DEBUG_NET_WARN_ON_ONCE(!skb_frag_size(frag));
skb_frag_off_add(frag, hdr_len);
skb->data_len -= hdr_len;
skb->tail += hdr_len;
}
shinfo->gso_size = rsc_seg_len;
shinfo->gso_segs = rsc_segments;
@ -1010,7 +1022,7 @@ static int gve_rx_complete_skb(struct gve_rx_ring *rx, struct napi_struct *napi,
return err;
}
if (skb_headlen(rx->ctx.skb_head) == 0)
if (rx->ctx.skb_head == napi->skb)
napi_gro_frags(napi);
else
napi_gro_receive(napi, rx->ctx.skb_head);