From 55911a9f4287c19bf7ef29aeace14044a6ed88cb Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 15 May 2024 14:53:31 +0200 Subject: rcu: Remove full memory barrier on RCU stall printout RCU stall printout fetches the EQS state of a CPU with a preceding full memory barrier. However there is nothing to order this read against at this debugging stage. It is inherently racy when performed remotely. Do a plain read instead. This was the last user of rcu_dynticks_snap(). Signed-off-by: Frederic Weisbecker Signed-off-by: Paul E. McKenney Reviewed-by: Boqun Feng Reviewed-by: Neeraj Upadhyay --- kernel/rcu/tree.c | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'kernel/rcu/tree.c') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 57d813781749..100094717bda 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -295,16 +295,6 @@ static void rcu_dynticks_eqs_online(void) ct_state_inc(RCU_DYNTICKS_IDX); } -/* - * Snapshot the ->dynticks counter with full ordering so as to allow - * stable comparison of this counter with past and future snapshots. - */ -static int rcu_dynticks_snap(int cpu) -{ - smp_mb(); // Fundamental RCU ordering guarantee. - return ct_dynticks_cpu_acquire(cpu); -} - /* * Return true if the snapshot returned from rcu_dynticks_snap() * indicates that RCU is in an extended quiescent state. -- cgit v1.2.3