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authorIngo Molnar <mingo@elte.hu>2007-06-17 18:37:45 +0200
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-06-18 11:52:55 -0700
commita0f98a1cb7d27c656de450ba56efd31bdc59065e (patch)
tree8ff6c211cd190aa6152e8ef4bd9f142277ed4a9f /kernel/sched.c
parent4cc21505a09354ade787de368bd697a1bba3b213 (diff)
sched: fix SysRq-N (normalize RT tasks)
Gene Heskett reported the following problem while testing CFS: SysRq-N is not always effective in normalizing tasks back to SCHED_OTHER. The reason for that turns out to be the following bug: - normalize_rt_tasks() uses for_each_process() to iterate through all tasks in the system. The problem is, this method does not iterate through all tasks, it iterates through all thread groups. The proper mechanism to enumerate over all threads is to use a do_each_thread() + while_each_thread() loop. Reported-by: Gene Heskett <gene.heskett@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 13cdab3b4c4..49be34e1f0b 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7071,12 +7071,13 @@ EXPORT_SYMBOL(__might_sleep);
void normalize_rt_tasks(void)
{
struct prio_array *array;
- struct task_struct *p;
+ struct task_struct *g, *p;
unsigned long flags;
struct rq *rq;
read_lock_irq(&tasklist_lock);
- for_each_process(p) {
+
+ do_each_thread(g, p) {
if (!rt_task(p))
continue;
@@ -7094,7 +7095,8 @@ void normalize_rt_tasks(void)
__task_rq_unlock(rq);
spin_unlock_irqrestore(&p->pi_lock, flags);
- }
+ } while_each_thread(g, p);
+
read_unlock_irq(&tasklist_lock);
}