From: Eric Dumazet edumazet@google.com
commit 8dc1c444df193701910f5e80b5d4caaf705a8fb0 upstream.
Commit c80794323e82 ("net: Fix packet reordering caused by GRO and listified RX cooperation") had the unfortunate effect of adding latencies in common workloads.
Before the patch, GRO packets were immediately passed to upper stacks.
After the patch, we can accumulate quite a lot of GRO packets (depdending on NAPI budget).
My fix is counting in napi->rx_count number of segments instead of number of logical packets.
Fixes: c80794323e82 ("net: Fix packet reordering caused by GRO and listified RX cooperation") Signed-off-by: Eric Dumazet edumazet@google.com Bisected-by: John Sperbeck jsperbeck@google.com Tested-by: Jian Yang jianyang@google.com Cc: Maxim Mikityanskiy maximmi@mellanox.com Reviewed-by: Saeed Mahameed saeedm@nvidia.com Reviewed-by: Edward Cree ecree.xilinx@gmail.com Reviewed-by: Alexander Lobakin alobakin@pm.me Link: https://lore.kernel.org/r/20210204213146.4192368-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/dev.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
--- a/net/core/dev.c +++ b/net/core/dev.c @@ -5723,10 +5723,11 @@ static void gro_normal_list(struct napi_ /* Queue one GRO_NORMAL SKB up for list processing. If batch size exceeded, * pass the whole batch up to the stack. */ -static void gro_normal_one(struct napi_struct *napi, struct sk_buff *skb) +static void gro_normal_one(struct napi_struct *napi, struct sk_buff *skb, int segs) { list_add_tail(&skb->list, &napi->rx_list); - if (++napi->rx_count >= gro_normal_batch) + napi->rx_count += segs; + if (napi->rx_count >= gro_normal_batch) gro_normal_list(napi); }
@@ -5765,7 +5766,7 @@ static int napi_gro_complete(struct napi }
out: - gro_normal_one(napi, skb); + gro_normal_one(napi, skb, NAPI_GRO_CB(skb)->count); return NET_RX_SUCCESS; }
@@ -6055,7 +6056,7 @@ static gro_result_t napi_skb_finish(stru { switch (ret) { case GRO_NORMAL: - gro_normal_one(napi, skb); + gro_normal_one(napi, skb, 1); break;
case GRO_DROP: @@ -6143,7 +6144,7 @@ static gro_result_t napi_frags_finish(st __skb_push(skb, ETH_HLEN); skb->protocol = eth_type_trans(skb, skb->dev); if (ret == GRO_NORMAL) - gro_normal_one(napi, skb); + gro_normal_one(napi, skb, 1); break;
case GRO_DROP: