From a8e4f2eaecc9bfa4954adf79a04f4f22fddd829c Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Tue, 5 Apr 2011 17:23:49 +0200
Subject: [PATCH] sched: Delay task_contributes_to_load()
In prepratation of having to call task_contributes_to_load() without
holding rq->lock, we need to store the result until we do and can
update the rq accounting accordingly.
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152729.151523907@chello.nl
---
include/linux/sched.h | 1 +
kernel/sched.c | 16 ++++------------
2 files changed, 5 insertions(+), 12 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7f5732f8c618..25c50317ddc1 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1273,6 +1273,7 @@ struct task_struct {
/* Revert to default priority/policy when forking */
unsigned sched_reset_on_fork:1;
+ unsigned sched_contributes_to_load:1;
pid_t pid;
pid_t tgid;
diff --git a/kernel/sched.c b/kernel/sched.c
index 7a5eb2620785..fd32b78c123c 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2519,18 +2519,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
if (unlikely(task_running(rq, p)))
goto out_activate;
- /*
- * In order to handle concurrent wakeups and release the rq->lock
- * we put the task in TASK_WAKING state.
- *
- * First fix up the nr_uninterruptible count:
- */
- if (task_contributes_to_load(p)) {
- if (likely(cpu_online(orig_cpu)))
- rq->nr_uninterruptible--;
- else
- this_rq()->nr_uninterruptible--;
- }
+ p->sched_contributes_to_load = !!task_contributes_to_load(p);
p->state = TASK_WAKING;
if (p->sched_class->task_waking) {
@@ -2555,6 +2544,9 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
WARN_ON(task_cpu(p) != cpu);
WARN_ON(p->state != TASK_WAKING);
+ if (p->sched_contributes_to_load)
+ rq->nr_uninterruptible--;
+
out_activate:
#endif /* CONFIG_SMP */
ttwu_activate(rq, p, en_flags);
--
2.34.1