Re: mac80211: NOHZ: local_softirq_pending 08
From: Oliver Hartkopp <hidden>
Date: 2009-09-11 16:07:39
Also in:
linux-wireless
Michael Buesch wrote:
quoted hunk
On Friday 11 September 2009 16:57:54 Kalle Valo wrote:quoted
Michael Buesch [off-list ref] writes:quoted
Hi,Hallo,quoted
mac80211 (or some other part of the networking stack) triggers this warning in the NOHZ code: NOHZ: local_softirq_pending 08 08 seems to be NET_RX_SOFTIRQ. It happens, because my test driver b43 handles all RX and TX-status callbacks in process context. I guess some part of the networking stack expects RX to be in tasklet and/or softirq context. We also have a report of this warning in wl1251, so it's probably not a b43 problem.Yes, I see this with wl1251. It uses workqueues everywhere.This patch seems to fix it. Signed-off-by: Michael Buesch <redacted> Index: wireless-testing/net/mac80211/cfg.c ===================================================================--- wireless-testing.orig/net/mac80211/cfg.c 2009-08-09 18:47:11.000000000 +0200 +++ wireless-testing/net/mac80211/cfg.c 2009-09-11 16:59:12.000000000 +0200@@ -606,7 +606,7 @@ static void ieee80211_send_layer2_update skb->dev = sta->sdata->dev; skb->protocol = eth_type_trans(skb, sta->sdata->dev); memset(skb->cb, 0, sizeof(skb->cb)); - netif_rx(skb); + ieee80211_netif_rx(skb); } static void sta_apply_parameters(struct ieee80211_local *local,Index: wireless-testing/net/mac80211/ieee80211_i.h ===================================================================--- wireless-testing.orig/net/mac80211/ieee80211_i.h 2009-08-23 00:06:41.000000000 +0200 +++ wireless-testing/net/mac80211/ieee80211_i.h 2009-09-11 17:02:05.000000000 +0200@@ -1053,6 +1053,14 @@ void ieee80211_tx_pending(unsigned long int ieee80211_monitor_start_xmit(struct sk_buff *skb, struct net_device *dev); int ieee80211_subif_start_xmit(struct sk_buff *skb, struct net_device *dev); +/* rx handling */ +static inline int ieee80211_netif_rx(struct sk_buff *skb) +{ + if (in_interrupt()) + return netif_rx(skb); + return netif_rx_ni(skb); +} +
Hello Michael,
i know this NOHZ warning from the CAN stack also - but now, i know what caused
this warning. I fixed it in my local tree and it works. Thanks!
As there are several users in the kernel do exact this test and call the
appropriate netif_rx() function, i would suggest to create a static inline
function:
static inline int netif_rx_ti(struct sk_buff *skb)
{
if (in_interrupt())
return netif_rx(skb);
return netif_rx_ni(skb);
}
('ti' for test in_interrupt())
in include/linux/netdevice.h
What do you think about that?
Regards,
Oliver
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