iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

rcu/exp: Remove full barrier upon main thread wakeup

Browse Source 
When an expedited grace period is ending, care must be taken so that all
the quiescent states propagated up to the root are correctly ordered
against the wake up of the main expedited grace period workqueue.

This ordering is already carried through the root rnp locking augmented
by an smp_mb__after_unlock_lock() barrier.

Therefore the explicit smp_mb() placed before the wake up is not needed
and can be removed.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
This commit is contained in:
Frederic Weisbecker 2023-12-19 00:19:16 +01:00 committed by Boqun Feng
parent 41bccc98fb
commit a7e4074dcc
1 changed files with 2 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
kernel/rcu/tree_exp.h
View File

@ -198,10 +198,9 @@ static void __rcu_report_exp_rnp(struct rcu_node *rnp,
}
if (rnp->parent == NULL) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
if (wake) {
smp_mb(); /* EGP done before wake_up(). */
if (wake)
swake_up_one_online(&rcu_state.expedited_wq);
}
break;
}
mask = rnp->grpmask;