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authorWanpeng Li <wanpeng.li@linux.intel.com>2014-10-31 06:39:31 +0800
committerIngo Molnar <mingo@kernel.org>2014-11-04 07:17:52 +0100
commit308a623a40ce168eb234ea82c2bd13ff85a098d9 (patch)
treede29313f91c8c98c353e422cdaf423b6494dcbb8 /kernel/sched/rt.c
parent75e23e49dbdd86aace375f599062aa67483a001b (diff)
downloadlinux-308a623a40ce168eb234ea82c2bd13ff85a098d9.tar.bz2
sched/rt: Clean up check_preempt_equal_prio()
This patch checks if current can be pushed/pulled somewhere else in advance to make logic clear, the same behavior as dl class. - If current can't be migrated, useless to reschedule, let's hope task can move out. - If task is migratable, so let's not schedule it and see if it can be pushed or pulled somewhere else. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Kirill Tkhai <ktkhai@parallels.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1414708776-124078-1-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/rt.c')
-rw-r--r--kernel/sched/rt.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index d024e6ce30ba..3d14312db7ea 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1351,16 +1351,22 @@ out:
static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
{
- if (rq->curr->nr_cpus_allowed == 1)
+ /*
+ * Current can't be migrated, useless to reschedule,
+ * let's hope p can move out.
+ */
+ if (rq->curr->nr_cpus_allowed == 1 ||
+ !cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
return;
+ /*
+ * p is migratable, so let's not schedule it and
+ * see if it is pushed or pulled somewhere else.
+ */
if (p->nr_cpus_allowed != 1
&& cpupri_find(&rq->rd->cpupri, p, NULL))
return;
- if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
- return;
-
/*
* There appears to be other cpus that can accept
* current and none to run 'p', so lets reschedule