Messages in this thread Patch in this message | | | Date | Wed, 27 Feb 2008 16:38:29 +0530 | From | Dhaval Giani <> | Subject | [PATCH] sched: don't allow rt_runtime_us to be zero for groups having rt tasks |
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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 to 0 otherwise bad things will happen.
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> --- kernel/sched.c | 19 +++++++++++++++++++ 1 files changed, 19 insertions(+)
Index: linux-2.6.25-rc3/kernel/sched.c =================================================================== --- linux-2.6.25-rc3.orig/kernel/sched.c +++ linux-2.6.25-rc3/kernel/sched.c @@ -7960,6 +7960,17 @@ static int __rt_schedulable(struct task_ 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 *p; + for_each_process(p) { + if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg) + return 1; + } + return 0; +} + int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) { u64 rt_runtime, rt_period; @@ -7971,6 +7982,13 @@ int sched_group_set_rt_runtime(struct ta rt_runtime = rt_period; mutex_lock(&rt_constraints_mutex); + read_lock(&tasklist_lock); + if (rt_runtime_us == 0) { + if (tg_has_rt_tasks(tg)) { + err = -EINVAL; + goto unlock; + } + } if (!__rt_schedulable(tg, rt_period, rt_runtime)) { err = -EINVAL; goto unlock; @@ -7979,6 +7997,7 @@ int sched_group_set_rt_runtime(struct ta rt_runtime = RUNTIME_INF; tg->rt_runtime = rt_runtime; unlock: + read_unlock(&tasklist_lock); mutex_unlock(&rt_constraints_mutex); return err; -- regards, Dhaval
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