Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 10/19] rcu/nocb: Set SEGCBLIST_SOFTIRQ_ONLY at the very last stage of de-offloading | Date | Fri, 13 Nov 2020 13:13:25 +0100 |
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Set SEGCBLIST_SOFTIRQ_ONLY once everything is settled. After that, the callbacks are handled locklessly and locally.
Inspired-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Neeraj Upadhyay <neeraju@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Boqun Feng <boqun.feng@gmail.com> --- kernel/rcu/tree_plugin.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index dfb4b62c6b88..b68714e5ce64 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2352,7 +2352,14 @@ static int __rcu_nocb_rdp_deoffload(struct rcu_data *rdp) */ rcu_nocb_lock_irqsave(rdp, flags); rcu_nocb_flush_bypass(rdp, NULL, jiffies); - rcu_nocb_unlock_irqrestore(rdp, flags); + rcu_segcblist_set_flags(cblist, SEGCBLIST_SOFTIRQ_ONLY); + /* + * With SEGCBLIST_SOFTIRQ_ONLY, we can't use + * rcu_nocb_unlock_irqrestore() anymore. Theoretically we + * could set SEGCBLIST_SOFTIRQ_ONLY with cb unlocked and IRQs + * disabled now, but let's be paranoid. + */ + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); return ret; } -- 2.25.1
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