Thread (16 messages) flat view 16 messages, 7 authors, 2013-06-13

Re: [PATCH net-next 2/2] net:add socket option for low latency polling

From: Eric Dumazet <hidden>
Date: 2013-06-11 14:45:38
Also in: lkml

On Tue, 2013-06-11 at 17:24 +0300, Eliezer Tamir wrote:
adds a socket option for low latency polling.
This allows overriding the global sysctl value with a per-socket one.

Signed-off-by: Eliezer Tamir <redacted>
---

 
-static inline cycles_t ll_end_time(void)
+static inline cycles_t ll_end_time(struct sock *sk)
 {
-	return TSC_MHZ * ACCESS_ONCE(sysctl_net_ll_poll) + get_cycles();
+	return TSC_MHZ * ACCESS_ONCE(sk->sk_ll_usec) + get_cycles();
 }
Hmm, sk_ll_usec is an unsigned int.

(cycles_t)TSC_MHZ * ACCESS_ONCE(sk->sk_ll_usec) + get_cycles();
 
+#ifdef CONFIG_NET_LL_RX_POLL
+	case SO_LL:
+		if (!capable(CAP_NET_ADMIN))
+			ret = -EACCES;
+		else {
+			unsigned long ulval;
Why an "unsigned long" ?

+
+			if (!copy_from_user(&ulval, optval, sizeof(ulval))
+							&& ulval >= 0)
+				sk->sk_ll_usec = ulval;
+
+			else
+				ret = -EINVAL;
Just use
	sk->sk_ll_usec = val;
quoted hunk ↗ jump to hunk
+
+		}
+		break;
+#endif
 	default:
 		ret = -ENOPROTOOPT;
 		break;
@@ -944,6 +961,7 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 
 	union {
 		int val;
+		unsigned long ulval;
Why an unsigned long ? 32bit are more than enough.
quoted hunk ↗ jump to hunk
 		struct linger ling;
 		struct timeval tm;
 	} v;
@@ -1170,6 +1188,13 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = sock_flag(sk, SOCK_SELECT_ERR_QUEUE);
 		break;
 
+#ifdef CONFIG_NET_LL_RX_POLL
+	case SO_LL:
+		len = sizeof(v.ulval);
+		v.ulval = sk->sk_ll_usec;
+		break;
+#endif
+



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