sched/rt: Do not submit new work when PI-blocked

tip:sched/core tip-bot for Thomas Gleixner 1 participant 1 message Mar 1, 2012 Scheduler

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2012-03-01 12:22 UTC #0 lore raw

Commit-ID:  3c7d51843b03a6839e9ec7cda724e54d2319a63a
Gitweb:     http://git.kernel.org/tip/3c7d51843b03a6839e9ec7cda724e54d2319a63a
Author:     Thomas Gleixner <[email protected]>
AuthorDate: Sun, 17 Jul 2011 20:46:52 +0200
Committer:  Ingo Molnar <[email protected]>
CommitDate: Thu, 1 Mar 2012 10:46:54 +0100

sched/rt: Do not submit new work when PI-blocked

When we are PI-blocked then we want to get things done ASAP.

Signed-off-by Thomas Gleixner <[email protected]>

Acked-by Peter Zijlstra <[email protected]>

Link http://lkml.kernel.org/n/[email protected] open here

Signed-off-by Ingo Molnar <[email protected]>

---
 include/linux/sched.h |    8 ++++++++
 kernel/sched/core.c   |    2 +-
 2 files changed, 9 insertions(+), 1 deletions(-)

include/linux/sched.h +8 -0

index 03dd224..c628a91 100644
@@ -2082,12 +2082,20 @@ extern unsigned int sysctl_sched_cfs_bandwidth_slice;
 extern int rt_mutex_getprio(struct task_struct *p);
 extern void rt_mutex_setprio(struct task_struct *p, int prio);
 extern void rt_mutex_adjust_pi(struct task_struct *p);
+static inline bool tsk_is_pi_blocked(struct task_struct *tsk)
+{
+	return tsk->pi_blocked_on != NULL;
+}
 #else
 static inline int rt_mutex_getprio(struct task_struct *p)
 {
 	return p->normal_prio;
 }
 # define rt_mutex_adjust_pi(p)		do { } while (0)
+static inline bool tsk_is_pi_blocked(struct task_struct *tsk)
+{
+	return false;
+}
 #endif
 
 extern bool yield_to(struct task_struct *p, bool preempt);

kernel/sched/core.c +1 -1

index c2bbdec..25e06a5 100644
@@ -3227,7 +3227,7 @@ need_resched:
 
 static inline void sched_submit_work(struct task_struct *tsk)
 {
-	if (!tsk->state)
+	if (!tsk->state || tsk_is_pi_blocked(tsk))
 		return;
 	/*
 	 * If we are going to sleep and we have plugged IO queued,