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author | Juri Lelli <juri.lelli@arm.com> | 2014-09-19 13:22:39 +0400 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2014-09-24 16:46:56 +0400 |
commit | a5e7be3b28a235108c59561bea55eea1072b23b0 (patch) | |
tree | 57e8b7c8c7059cf4775a5742ea0cfd69e71a04ee /kernel | |
parent | be34f0f3e6aed6e828a8059247d169d38da128d7 (diff) | |
download | linux-a5e7be3b28a235108c59561bea55eea1072b23b0.tar.xz |
sched/deadline: Clear dl_entity params when setscheduling to different class
When a task is using SCHED_DEADLINE and the user setschedules it to a
different class its sched_dl_entity static parameters are not cleaned
up. This causes a bug if the user sets it back to SCHED_DEADLINE with
the same parameters again. The problem resides in the check we
perform at the very beginning of dl_overflow():
if (new_bw == p->dl.dl_bw)
return 0;
This condition is met in the case depicted above, so the function
returns and dl_b->total_bw is not updated (the p->dl.dl_bw is not
added to it). After this, admission control is broken.
This patch fixes the thing, properly clearing static parameters for a
task that ceases to use SCHED_DEADLINE.
Reported-by: Daniele Alessandrelli <daniele.alessandrelli@gmail.com>
Reported-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Reported-by: Vincent Legout <vincent@legout.info>
Tested-by: Luca Abeni <luca.abeni@unitn.it>
Tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Tested-by: Vincent Legout <vincent@legout.info>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Fabio Checconi <fchecconi@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1411118561-26323-2-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/sched/core.c | 19 | ||||
-rw-r--r-- | kernel/sched/deadline.c | 2 | ||||
-rw-r--r-- | kernel/sched/sched.h | 3 |
3 files changed, 20 insertions, 4 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a2841904f2d5..09bde2ab2a0a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1809,6 +1809,20 @@ int wake_up_state(struct task_struct *p, unsigned int state) } /* + * This function clears the sched_dl_entity static params. + */ +void __dl_clear_params(struct task_struct *p) +{ + struct sched_dl_entity *dl_se = &p->dl; + + dl_se->dl_runtime = 0; + dl_se->dl_deadline = 0; + dl_se->dl_period = 0; + dl_se->flags = 0; + dl_se->dl_bw = 0; +} + +/* * Perform scheduler related setup for a newly forked process p. * p is forked by current. * @@ -1832,10 +1846,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) RB_CLEAR_NODE(&p->dl.rb_node); hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); - p->dl.dl_runtime = p->dl.runtime = 0; - p->dl.dl_deadline = p->dl.deadline = 0; - p->dl.dl_period = 0; - p->dl.flags = 0; + __dl_clear_params(p); INIT_LIST_HEAD(&p->rt.run_list); diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index aaa5abbff2f1..efb94124420d 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1565,6 +1565,8 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p) if (hrtimer_active(&p->dl.dl_timer) && !dl_policy(p->policy)) hrtimer_try_to_cancel(&p->dl.dl_timer); + __dl_clear_params(p); + #ifdef CONFIG_SMP /* * Since this might be the only -deadline task on the rq, diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 1bc6aad1391a..76f3a38a401c 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -130,6 +130,9 @@ struct rt_bandwidth { u64 rt_runtime; struct hrtimer rt_period_timer; }; + +void __dl_clear_params(struct task_struct *p); + /* * To keep the bandwidth of -deadline tasks and groups under control * we need some place where: |