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authorPeter Zijlstra <peterz@infradead.org>2014-01-15 16:33:20 +0100
committerIngo Molnar <mingo@kernel.org>2014-01-16 09:27:15 +0100
commit39fd8fd22b3224ec6819d33b3e34ae4da6a35f05 (patch)
tree89d90224b682be4aa979465d52d06263b179a98f
parente3de300d1212b42aa9d0d6031b12fca06ac00dd9 (diff)
downloadlinux-39fd8fd22b3224ec6819d33b3e34ae4da6a35f05.tar.gz
sched: Fix up scheduler syscall LTP fails
Wu reported LTP failures:

  > ltp.sched_setparam02.1.TFAIL
  > ltp.sched_setparam02.2.TFAIL
  > ltp.sched_setparam02.3.TFAIL
  > ltp.sched_setparam03.1.TFAIL

There were 2 things wrong; firstly __setscheduler() failed on
sched_setparam()'s policy = -1, fix that by reading from p->policy in
that case.

Secondly, getparam() (and getattr()) would still report !0
sched_priority for !FIFO/RR tasks after having been such. So
unconditionally set p->rt_priority.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Fixes: d50dde5a10f3 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI")
Link: http://lkml.kernel.org/r/20140115153320.GH31570@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/sched/core.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c1b3d7e04f0f..e9212eb354b8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3172,15 +3172,23 @@ static void __setscheduler(struct rq *rq, struct task_struct *p,
 {
 	int policy = attr->sched_policy;
 
+	if (policy == -1) /* setparam */
+		policy = p->policy;
+
 	p->policy = policy;
 
 	if (dl_policy(policy))
 		__setparam_dl(p, attr);
-	else if (rt_policy(policy))
-		p->rt_priority = attr->sched_priority;
-	else
+	else if (fair_policy(policy))
 		p->static_prio = NICE_TO_PRIO(attr->sched_nice);
 
+	/*
+	 * __sched_setscheduler() ensures attr->sched_priority == 0 when
+	 * !rt_policy. Always setting this ensures that things like
+	 * getparam()/getattr() don't report silly values for !rt tasks.
+	 */
+	p->rt_priority = attr->sched_priority;
+
 	p->normal_prio = normal_prio(p);
 	p->prio = rt_mutex_getprio(p);