read_lock_irqsave(tasklist_lock) in print_rq() looks strange. We do
not need to disable irqs, and they are already disabled by the caller.
And afaics this lock buys nothing, we can rely on rcu_read_lock().
In this case it makes sense to also move rcu_read_lock/unlock from
the caller to print_rq().
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
kernel/sched/debug.c | 7 ++-----
1 files changed, 2 insertions(+), 5 deletions(-)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index c7fe1ea..ce33780 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -150,7 +150,6 @@ print_task(struct seq_file *m, struct rq *rq, struct
task_struct *p)
static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
{
struct task_struct *g, *p;
- unsigned long flags;
SEQ_printf(m,
"\nrunnable tasks:\n"
@@ -159,14 +158,14 @@ static void print_rq(struct seq_file *m, struct rq *rq,
int rq_cpu)
"------------------------------------------------------"
"----------------------------------------------------\n");
- read_lock_irqsave(&tasklist_lock, flags);
+ rcu_read_lock();
for_each_process_thread(g, p) {
if (task_cpu(p) != rq_cpu)
continue;
print_task(m, rq, p);
}
- read_unlock_irqrestore(&tasklist_lock, flags);
+ rcu_read_unlock();
}
void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
@@ -331,9 +330,7 @@ do {
\
print_cfs_stats(m, cpu);
print_rt_stats(m, cpu);
- rcu_read_lock();
print_rq(m, rq, cpu);
- rcu_read_unlock();
spin_unlock_irqrestore(&sched_debug_lock, flags);
SEQ_printf(m, "\n");
}
--
1.5.5.1
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