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| author | Zhang, Yanmin <yanmin_zhang@linux.intel.com> | 2008-09-09 11:26:33 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-09-11 09:34:28 +0200 |
| commit | baf25731e54d06eb13dc4eda78c6dc7da4ce84e8 (patch) | |
| tree | af5cbd2b004a2258ebfd332d4871249d1c32f41f /kernel | |
| parent | 291c54ff764d12ecc9a916cb478a0bbb45c5990e (diff) | |
| download | linux-baf25731e54d06eb13dc4eda78c6dc7da4ce84e8.tar.gz linux-baf25731e54d06eb13dc4eda78c6dc7da4ce84e8.tar.bz2 linux-baf25731e54d06eb13dc4eda78c6dc7da4ce84e8.zip | |
sched: fix 2.6.27-rc5 couldn't boot on tulsa machine randomly
On my tulsa x86-64 machine, kernel 2.6.25-rc5 couldn't boot randomly.
Basically, function __enable_runtime forgets to reset rt_rq->rt_throttled
to 0. When every cpu is up, per-cpu migration_thread is created and it runs
very fast, sometimes to mark the corresponding rt_rq->rt_throttled to 1 very
quickly. After all cpus are up, with below calling chain:
sched_init_smp => arch_init_sched_domains => build_sched_domains => ...
=> cpu_attach_domain => rq_attach_root => set_rq_online => ...
=> _enable_runtime
_enable_runtime is called against every rt_rq again, so rt_rq->rt_time is
reset to 0, but rt_rq->rt_throttled might be still 1. Later on function
do_sched_rt_period_timer couldn't reset it, and all RT tasks couldn't be
scheduled to run on that cpu. here is RT task migration_thread which is
woken up when a task is migrated to another cpu.
Below patch fixes it against 2.6.27-rc5.
Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched_rt.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 552310798dad..1113157b2058 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -350,6 +350,7 @@ static void __enable_runtime(struct rq *rq) spin_lock(&rt_rq->rt_runtime_lock); rt_rq->rt_runtime = rt_b->rt_runtime; rt_rq->rt_time = 0; + rt_rq->rt_throttled = 0; spin_unlock(&rt_rq->rt_runtime_lock); spin_unlock(&rt_b->rt_runtime_lock); } |