Patchwork [215/241] net-rps: Fix brokeness causing OOO packets

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Submitter Herton Ronaldo Krzesinski
Date Dec. 13, 2012, 1:59 p.m.
Message ID <1355407206-17100-216-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/206061/
State New
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Comments

Herton Ronaldo Krzesinski - Dec. 13, 2012, 1:59 p.m.
3.5.7.2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tom Herbert <therbert@google.com>

commit baefa31db2f2b13a05d1b81bdf2d20d487f58b0a upstream.

In commit c445477d74ab3779 which adds aRFS to the kernel, the CPU
selected for RFS is not set correctly when CPU is changing.
This is causing OOO packets and probably other issues.

Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 net/core/dev.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Patch

diff --git a/net/core/dev.c b/net/core/dev.c
index 75845ba..3ad746b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2761,8 +2761,10 @@  static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
 		if (unlikely(tcpu != next_cpu) &&
 		    (tcpu == RPS_NO_CPU || !cpu_online(tcpu) ||
 		     ((int)(per_cpu(softnet_data, tcpu).input_queue_head -
-		      rflow->last_qtail)) >= 0))
+		      rflow->last_qtail)) >= 0)) {
+			tcpu = next_cpu;
 			rflow = set_rps_cpu(dev, skb, rflow, next_cpu);
+		}
 
 		if (tcpu != RPS_NO_CPU && cpu_online(tcpu)) {
 			*rflowp = rflow;