Re: [PATCH v5 net-next 2/5] net: implement support for low latency socket polling

On 28/05/2013 03:26, Eric Dumazet wrote:

On Mon, 2013-05-27 at 10:44 +0300, Eliezer Tamir wrote:

quoted

diff --git a/include/net/sock.h b/include/net/sock.h
index 66772cf..c7c3ea6 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h

@@ -281,6 +281,7 @@ struct cg_proto;
    *	@sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
    *	@sk_backlog_rcv: callback to process the backlog
    *	@sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
+  *	@sk_napi_id: id of the last napi context to receive data for sk
   */
  struct sock {
  	/*

@@ -399,6 +400,9 @@ struct sock {
  	int			(*sk_backlog_rcv)(struct sock *sk,
  						  struct sk_buff *skb);
  	void                    (*sk_destruct)(struct sock *sk);
+#ifdef CONFIG_NET_LL_RX_POLL
+	unsigned int		sk_napi_id;
+#endif
  };

I believe this is a bad choice for data locality.

I would rather move it in the same cache line than sk_rxhash

I will move it to right after sk_rxhash.

-Eliezer