From 8dc1c444df193701910f5e80b5d4caaf705a8fb0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 4 Feb 2021 13:31:46 -0800 Subject: [PATCH] net: gro: do not keep too many GRO packets in napi->rx_list 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 Bisected-by: John Sperbeck Tested-by: Jian Yang Cc: Maxim Mikityanskiy Reviewed-by: Saeed Mahameed Reviewed-by: Edward Cree Reviewed-by: Alexander Lobakin Link: https://lore.kernel.org/r/20210204213146.4192368-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski --- net/core/dev.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index a979b86dbacd..449b45b843d4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5735,10 +5735,11 @@ static void gro_normal_list(struct napi_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); } @@ -5777,7 +5778,7 @@ static int napi_gro_complete(struct napi_struct *napi, struct sk_buff *skb) } out: - gro_normal_one(napi, skb); + gro_normal_one(napi, skb, NAPI_GRO_CB(skb)->count); return NET_RX_SUCCESS; } @@ -6067,7 +6068,7 @@ static gro_result_t napi_skb_finish(struct napi_struct *napi, { switch (ret) { case GRO_NORMAL: - gro_normal_one(napi, skb); + gro_normal_one(napi, skb, 1); break; case GRO_DROP: @@ -6155,7 +6156,7 @@ static gro_result_t napi_frags_finish(struct napi_struct *napi, __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: -- 2.20.1