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authorOleg Nesterov <oleg@redhat.com>2014-09-21 21:33:41 +0200
committerIngo Molnar <mingo@kernel.org>2014-09-24 14:47:04 +0200
commit5bd96ab6fef66ec6b9f54134364e618fd0f8f2f3 (patch)
treeabb0e7787c12ea0a37e48277b0a6e8f11d21ce69 /kernel/sched
parent3472eaa1f12e217e2b8b0ef658ff861b2308cbbd (diff)
sched: print_rq(): Don't use tasklist_lock
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 <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140921193341.GA28628@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/debug.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index c7fe1ea0e8ab..ce33780d8f20 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");
}