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| author | Brian Silverman <brian@peloton-tech.com> | 2015-02-18 16:23:56 -0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2015-05-09 23:16:32 +0100 |
| commit | 01e86182d2356449cca1398c8fa0360e5071fd82 (patch) | |
| tree | 9f890e6984bd6b31833be8054bbe2f298e80fd1d /kernel | |
| parent | f3022d3db336e281ec070b876c3f0600a712a2f4 (diff) | |
| download | kernel_samsung_smdk4412-01e86182d2356449cca1398c8fa0360e5071fd82.zip kernel_samsung_smdk4412-01e86182d2356449cca1398c8fa0360e5071fd82.tar.gz kernel_samsung_smdk4412-01e86182d2356449cca1398c8fa0360e5071fd82.tar.bz2 | |
sched: Fix RLIMIT_RTTIME when PI-boosting to RT
commit 746db9443ea57fd9c059f62c4bfbf41cf224fe13 upstream.
When non-realtime tasks get priority-inheritance boosted to a realtime
scheduling class, RLIMIT_RTTIME starts to apply to them. However, the
counter used for checking this (the same one used for SCHED_RR
timeslices) was not getting reset. This meant that tasks running with a
non-realtime scheduling class which are repeatedly boosted to a realtime
one, but never block while they are running realtime, eventually hit the
timeout without ever running for a time over the limit. This patch
resets the realtime timeslice counter when un-PI-boosting from an RT to
a non-RT scheduling class.
I have some test code with two threads and a shared PTHREAD_PRIO_INHERIT
mutex which induces priority boosting and spins while boosted that gets
killed by a SIGXCPU on non-fixed kernels but doesn't with this patch
applied. It happens much faster with a CONFIG_PREEMPT_RT kernel, and
does happen eventually with PREEMPT_VOLUNTARY kernels.
Signed-off-by: Brian Silverman <brian@peloton-tech.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: austin@peloton-tech.com
Link: http://lkml.kernel.org/r/1424305436-6716-1-git-send-email-brian@peloton-tech.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 29e5bf1..fe33d0f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5224,8 +5224,11 @@ void rt_mutex_setprio(struct task_struct *p, int prio) if (rt_prio(prio)) p->sched_class = &rt_sched_class; - else + else { + if (rt_prio(oldprio)) + p->rt.timeout = 0; p->sched_class = &fair_sched_class; + } p->prio = prio; |