Commit 23651d9b authored Jul 10, 2019 by Paul E. McKenney

rcu/nocb: Advance CBs after merge in rcutree_migrate_callbacks()

The rcutree_migrate_callbacks() invokes rcu_advance_cbs() on both the
offlined CPU's ->cblist and that of the surviving CPU, then merges
them. However, after the merge, and of the offlined CPU's callbacks
that were not ready to be invoked will no longer be associated with a
grace-period number. This commit therefore invokes rcu_advance_cbs()
one more time on the merged ->cblist in order to assign a grace-period
number to these callbacks.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

parent 273f0340

kernel/rcu/tree.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -3205,6 +3205,7 @@ void rcutree_migrate_callbacks(int cpu)
		needwake = rcu_advance_cbs(my_rnp, rdp) \|\|
		rcu_advance_cbs(my_rnp, my_rdp);
		rcu_segcblist_merge(&my_rdp->cblist, &rdp->cblist);
		needwake = needwake \|\| rcu_advance_cbs(my_rnp, my_rdp);
		rcu_segcblist_disable(&rdp->cblist);
		WARN_ON_ONCE(rcu_segcblist_empty(&my_rdp->cblist) !=
		!rcu_segcblist_n_cbs(&my_rdp->cblist));

Admin message