On Tue, Jul 08, 2014 at 08:53:27AM +0000, xiaofeng.yan wrote:
> static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
> {
> - s64 delta = p->dl.dl_runtime - p->dl.runtime;
> -
> - if (delta > 10000)
> - hrtick_start(rq, p->dl.runtime);
> + delta = max_t(s64, 10000LL, delta);
> + hrtick_start(rq, delta);
> }
no, no, no. I said to unify the test.
---
kernel/sched/core.c | 9 ++++++++-
kernel/sched/deadline.c | 3 +--
kernel/sched/fair.c | 7 -------
3 files changed, 9 insertions(+), 10 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e1a2f31bb0cb..c7b8a6fbac66 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -444,7 +444,14 @@ static void __hrtick_start(void *arg)
void hrtick_start(struct rq *rq, u64 delay)
{
struct hrtimer *timer = &rq->hrtick_timer;
- ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
+ ktime_t time;
+
+ /*
+ * Don't schedule slices shorter than 10000ns, that just
+ * doesn't make sense and can cause timer DoS.
+ */
+ delta = max_t(s64, delta, 10000LL);
+ time = ktime_add_ns(timer->base->get_time(), delay);
hrtimer_set_expires(timer, time);
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index fc4f98b1258f..e1e24eea8061 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -999,8 +999,7 @@ static void start_hrtick_dl(struct rq *rq, struct
task_struct *p)
{
s64 delta = p->dl.dl_runtime - p->dl.runtime;
- if (delta > 10000)
- hrtick_start(rq, p->dl.runtime);
+ hrtick_start(rq, p->dl.runtime);
}
#endif
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 923fe32db6b3..713c58d2a7b0 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3901,13 +3901,6 @@ static void hrtick_start_fair(struct rq *rq, struct
task_struct *p)
return;
}
- /*
- * Don't schedule slices shorter than 10000ns, that just
- * doesn't make sense. Rely on vruntime for fairness.
- */
- if (rq->curr != p)
- delta = max_t(s64, 10000LL, delta);
-
hrtick_start(rq, delta);
}
}
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