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rcu: Remove full memory barrier on boot time eqs sanity check

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When the boot CPU initializes the per-CPU data on behalf of all possible
CPUs, a sanity check is performed on each of them to make sure none is
initialized in an extended quiescent state.

This check involves a full memory barrier which is useless at this early
boot stage.

Do a plain access instead.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
This commit is contained in:
Frederic Weisbecker 2024-05-15 14:53:30 +02:00 committed by Paul E. McKenney
parent 33c0860bf7
commit e7a3c8ea6e
1 changed files with 1 additions and 1 deletions
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2
kernel/rcu/tree.c
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@ -4786,7 +4786,7 @@ rcu_boot_init_percpu_data(int cpu)
rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu);
INIT_WORK(&rdp->strict_work, strict_work_handler);
WARN_ON_ONCE(ct->dynticks_nesting != 1);
WARN_ON_ONCE(rcu_dynticks_in_eqs(rcu_dynticks_snap(cpu)));
WARN_ON_ONCE(rcu_dynticks_in_eqs(ct_dynticks_cpu(cpu)));
rdp->barrier_seq_snap = rcu_state.barrier_sequence;
rdp->rcu_ofl_gp_seq = rcu_state.gp_seq;
rdp->rcu_ofl_gp_state = RCU_GP_CLEANED;