diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-09-21 21:33:41 +0200 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2019-05-02 18:05:51 +0200 |
| commit | b7013589d0ba53392d4a1b77873e20a2056b8793 (patch) | |
| tree | 25413d0bed3078455e8a786beb59bf66243a8281 | |
| parent | 8ba303e411964aec72f42f6fc5ed6fb5e5259b60 (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().
Change-Id: Iadf0de148e27623af4535abc40c77c1dfd1f9c76
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>
| -rw-r--r-- | 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 2dad25a3d..4d03fc426 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -188,7 +188,6 @@ 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" @@ -197,14 +196,14 @@ 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 (!p->on_rq || 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) @@ -370,9 +369,7 @@ 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"); } |