diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2008-03-28 16:25:26 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-03-28 16:25:26 -0700 |
| commit | 2ba2506ca7ca62c56edaa334b0fe61eb5eab6ab0 (patch) | |
| tree | 0a1b1f7046eff42e2323334b656543efdf85d38a /net/sched | |
| parent | 32aced7509cb20ef3ec67c9b56f5b55c41dd4f8d (diff) | |
| download | lwn-2ba2506ca7ca62c56edaa334b0fe61eb5eab6ab0.tar.gz lwn-2ba2506ca7ca62c56edaa334b0fe61eb5eab6ab0.zip | |
[NET]: Add preemption point in qdisc_run
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>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/sch_generic.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 10b5c0887fff..b741618e4d54 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -184,10 +184,22 @@ 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); } |