diff options
| author | Dhaval Giani <dhaval@linux.vnet.ibm.com> | 2008-02-28 15:21:56 +0530 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-03-07 16:43:00 +0100 |
| commit | 521f1a2489c41f8b1181b0a8eb52e1c34284d50b (patch) | |
| tree | cfe339df98dcb65aaae6c45021ac92cdf60c6540 /kernel/sched.c | |
| parent | 2692a2406b9262bbb101708815be99ec2988e48b (diff) | |
| download | linux-521f1a2489c41f8b1181b0a8eb52e1c34284d50b.tar.bz2 | |
sched: don't allow rt_runtime_us to be zero for groups having rt tasks
This patch checks if we can set the rt_runtime_us to 0. If there is a
realtime task in the group, we don't want to set the rt_runtime_us as 0
or bad things will happen. (that task wont get any CPU time despite
being TASK_RUNNNG)
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index b8ee864c7481..52b98675acb2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7750,6 +7750,17 @@ static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) return total + to_ratio(period, runtime) < global_ratio; } +/* Must be called with tasklist_lock held */ +static inline int tg_has_rt_tasks(struct task_group *tg) +{ + struct task_struct *g, *p; + do_each_thread(g, p) { + if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg) + return 1; + } while_each_thread(g, p); + return 0; +} + int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) { u64 rt_runtime, rt_period; @@ -7761,12 +7772,18 @@ int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) rt_runtime = RUNTIME_INF; mutex_lock(&rt_constraints_mutex); + read_lock(&tasklist_lock); + if (rt_runtime_us == 0 && tg_has_rt_tasks(tg)) { + err = -EBUSY; + goto unlock; + } if (!__rt_schedulable(tg, rt_period, rt_runtime)) { err = -EINVAL; goto unlock; } tg->rt_runtime = rt_runtime; unlock: + read_unlock(&tasklist_lock); mutex_unlock(&rt_constraints_mutex); return err; |