[PATCH v2 net-next] Revert "net: group sk_backlog and sk_receive_queue"

[PATCH v2 net-next] Revert "net: group sk_backlog and sk_receive_queue"

[Eric Dumazet]

This reverts commit 4effb335b5dab08cb6e2c38d038910f8b527cfc9.

This was a benefit for UDP flood case, which was later greatly improved
with commits 6471658dc66c ("udp: use skb_attempt_defer_free()")
and b650bf0977d3 ("udp: remove busylock and add per NUMA queues").

Apparently blamed commit added a regression for RAW sockets, possibly
because they do not use the dual RX queue strategy that UDP has.

sock_queue_rcv_skb_reason() and RAW recvmsg() compete for sk_receive_buf
and sk_rmem_alloc changes, and them being in the same
cache line reduce performance.

Fixes: 4effb335b5da ("net: group sk_backlog and sk_receive_queue")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202509281326.f605b4eb-lkp@intel.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: David Ahern <dsahern@kernel.org>
Cc: Kuniyuki Iwashima <kuniyu@google.com>
---
v2: added missing SOB (Simon feedback)

 include/net/sock.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 8c5b64f41ab72d2a28c066c2a5698eaff7973918..60bcb13f045c3144609908a36960528b33e4f71c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -395,6 +395,7 @@ struct sock {
 
 	atomic_t		sk_drops;
 	__s32			sk_peek_off;
+	struct sk_buff_head	sk_error_queue;
 	struct sk_buff_head	sk_receive_queue;
 	/*
 	 * The backlog queue is special, it is always used with
@@ -412,7 +413,6 @@ struct sock {
 	} sk_backlog;
 #define sk_rmem_alloc sk_backlog.rmem_alloc
 
-	struct sk_buff_head	sk_error_queue;
 	__cacheline_group_end(sock_write_rx);
 
 	__cacheline_group_begin(sock_read_rx);
-- 
2.51.0.570.gb178f27e6d-goog

Re: [PATCH v2 net-next] Revert "net: group sk_backlog and sk_receive_queue"

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 29 Sep 2025 18:21:12 +0000 you wrote:
> This reverts commit 4effb335b5dab08cb6e2c38d038910f8b527cfc9.
> 
> This was a benefit for UDP flood case, which was later greatly improved
> with commits 6471658dc66c ("udp: use skb_attempt_defer_free()")
> and b650bf0977d3 ("udp: remove busylock and add per NUMA queues").
> 
> Apparently blamed commit added a regression for RAW sockets, possibly
> because they do not use the dual RX queue strategy that UDP has.
> 
> [...]

Here is the summary with links:
  - [v2,net-next] Revert "net: group sk_backlog and sk_receive_queue"
    https://git.kernel.org/netdev/net-next/c/7d452516b67a

You are awesome, thank you!
-- 
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