From c342b42fa47f4257fccfeadc8e32c51b1be17a1f Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 23 Feb 2024 15:16:20 -0800 Subject: rcu-tasks: Make Tasks RCU wait idly for grace-period delays Currently, all waits for grace periods sleep at TASK_UNINTERRUPTIBLE, regardless of RCU flavor. This has worked well, but there have been cases where a longer-than-average Tasks RCU grace period has triggered softlockup splats, many of them, before the Tasks RCU CPU stall warning appears. These softlockup splats unnecessarily consume console bandwidth and complicate diagnosis of the underlying problem. Plus a long but not pathologically long Tasks RCU grace period might trigger a few softlockup splats before completing normally, which generates noise for no good reason. This commit therefore causes Tasks RCU grace periods to sleep at TASK_IDLE priority. If there really is a persistent problem, the eventual Tasks RCU CPU stall warning will flag it, and without the extra noise. Reported-by: Breno Leitao Signed-off-by: Paul E. McKenney Signed-off-by: Uladzislau Rezki (Sony) --- kernel/rcu/update.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/rcu/update.c') diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 46aaaa9fe339..f8436969e0c8 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -408,7 +408,7 @@ void wakeme_after_rcu(struct rcu_head *head) } EXPORT_SYMBOL_GPL(wakeme_after_rcu); -void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array, +void __wait_rcu_gp(bool checktiny, unsigned int state, int n, call_rcu_func_t *crcu_array, struct rcu_synchronize *rs_array) { int i; @@ -440,7 +440,7 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array, if (crcu_array[j] == crcu_array[i]) break; if (j == i) { - wait_for_completion(&rs_array[i].completion); + wait_for_completion_state(&rs_array[i].completion, state); destroy_rcu_head_on_stack(&rs_array[i].head); } } -- cgit v1.2.3-59-g8ed1b