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| author |   Paul E. McKenney <paulmck@kernel.org> | 2022-05-09 09:49:05 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-07-21 17:41:56 -0700 |
| commit | 82e445697d6a14d6b7462c13c613ebdd96468818 (patch) | |
| tree | 5e20c4e1673667c23ec440f27580acb6e8fa82d9 | |
| parent | rcu: Put panic_on_rcu_stall() after expedited RCU CPU stall warnings (diff) | |
| download | linux-dev-82e445697d6a14d6b7462c13c613ebdd96468818.tar.xz linux-dev-82e445697d6a14d6b7462c13c613ebdd96468818.zip | |
rcu: Diagnose extended sync_rcu_do_polled_gp() loops
This commit dumps out state when the sync_rcu_do_polled_gp() function
loops more than expected. This is a debugging aid.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
| -rw-r--r-- | kernel/rcu/tree_exp.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index f05a15b11fa0..4c7037b50703 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -970,6 +970,7 @@ EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); static void sync_rcu_do_polled_gp(struct work_struct *wp) { unsigned long flags; + int i = 0; struct rcu_node *rnp = container_of(wp, struct rcu_node, exp_poll_wq); unsigned long s; @@ -979,8 +980,12 @@ static void sync_rcu_do_polled_gp(struct work_struct *wp) raw_spin_unlock_irqrestore(&rnp->exp_poll_lock, flags); if (s == RCU_GET_STATE_COMPLETED) return; - while (!poll_state_synchronize_rcu(s)) + while (!poll_state_synchronize_rcu(s)) { synchronize_rcu_expedited(); + if (i == 10 || i == 20) + pr_info("%s: i = %d s = %lx gp_seq_polled = %lx\n", __func__, i, s, READ_ONCE(rcu_state.gp_seq_polled)); + i++; + } raw_spin_lock_irqsave(&rnp->exp_poll_lock, flags); s = rnp->exp_seq_poll_rq; if (poll_state_synchronize_rcu(s)) |