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authorHerbert Xu <herbert@gondor.apana.org.au>2008-04-06 23:41:50 -0700
committerChris Wright <chrisw@sous-sol.org>2008-04-18 18:53:25 -0700
commitd55db74d5dbb56eb8f4fc874a97af7294a3b3008 (patch)
treebe62df2bbbbb07e200778f1d1510cab37025c456
parent43bee598bd747dc6849d3c4f32a3a912200073c0 (diff)
NET: Add preemption point in qdisc_run
Upstream commit: 2ba2506ca7ca62c56edaa334b0fe61eb5eab6ab0 The qdisc_run loop is currently unbounded and runs entirely in a softirq. This is bad as it may create an unbounded softirq run. This patch fixes this by calling need_resched and breaking out if necessary. It also adds a break out if the jiffies value changes since that would indicate we've been transmitting for too long which starves other softirqs. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
-rw-r--r--net/sched/sch_generic.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index e595e6570ce0..78889556d123 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -178,10 +178,22 @@ static inline int qdisc_restart(struct net_device *dev)
void __qdisc_run(struct net_device *dev)
{
- do {
- if (!qdisc_restart(dev))
+ unsigned long start_time = jiffies;
+
+ while (qdisc_restart(dev)) {
+ if (netif_queue_stopped(dev))
+ break;
+
+ /*
+ * Postpone processing if
+ * 1. another process needs the CPU;
+ * 2. we've been doing it for too long.
+ */
+ if (need_resched() || jiffies != start_time) {
+ netif_schedule(dev);
break;
- } while (!netif_queue_stopped(dev));
+ }
+ }
clear_bit(__LINK_STATE_QDISC_RUNNING, &dev->state);
}