netdev - [PATCH RFC net-next] virtio_net: refill buffer right after being used

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 29 Jul 2011 15:44:08 -0700
From:	Shirley Ma <mashirle@...ibm.com>
To:	Rusty Russell <rusty@...tcorp.com.au>, mst@...hat.com
Cc:	kvm@...r.kernel.org, virtualization@...ts.osdl.org,
	netdev@...r.kernel.org
Subject: [PATCH RFC net-next] virtio_net: refill buffer right after being
 used

To even the latency, refill buffer right after being used.

Sign-off-by: Shirley Ma <xma@...ibm.com>
---

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 0c7321c..c8201d4 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -429,6 +429,22 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
 	return err;
 }
 
+static bool fill_one(struct virtio_net *vi, gfp_t gfp)
+{
+	int err;
+
+	if (vi->mergeable_rx_bufs)
+		err = add_recvbuf_mergeable(vi, gfp);
+	else if (vi->big_packets)
+		err = add_recvbuf_big(vi, gfp);
+	else
+		err = add_recvbuf_small(vi, gfp);
+
+	if (err >= 0)
+		++vi->num;
+	return err;
+}
+
 /* Returns false if we couldn't fill entirely (OOM). */
 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
 {
@@ -436,17 +452,10 @@ static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
 	bool oom;
 
 	do {
-		if (vi->mergeable_rx_bufs)
-			err = add_recvbuf_mergeable(vi, gfp);
-		else if (vi->big_packets)
-			err = add_recvbuf_big(vi, gfp);
-		else
-			err = add_recvbuf_small(vi, gfp);
-
+		err = fill_one(vi, gfp);
 		oom = err == -ENOMEM;
 		if (err < 0)
 			break;
-		++vi->num;
 	} while (err > 0);
 	if (unlikely(vi->num > vi->max))
 		vi->max = vi->num;
@@ -506,13 +515,13 @@ again:
 		receive_buf(vi->dev, buf, len);
 		--vi->num;
 		received++;
-	}
-
-	if (vi->num < vi->max / 2) {
-		if (!try_fill_recv(vi, GFP_ATOMIC))
+		if (fill_one(vi, GFP_ATOMIC) < 0)
 			schedule_delayed_work(&vi->refill, 0);
 	}
 
+	/* notify buffers are refilled */
+	virtqueue_kick(vi->rvq);
+
 	/* Out of packets? */
 	if (received < budget) {
 		napi_complete(napi);


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html