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Subject[PATCH v4 2/5] rcu/tree: Clarify comments about FQS loop reporting quiescent states
Date
At least since v4.19, the FQS loop no longer reports quiescent states
for offline CPUs unless it is an emergency.

This commit therefore fixes the comment in rcu_gp_init() to match the
current code.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
kernel/rcu/tree.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index a49fa3b60faa..2fb66cdbfa25 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1701,9 +1701,11 @@ static bool rcu_gp_init(void)

/*
* Apply per-leaf buffered online and offline operations to the
- * rcu_node tree. Note that this new grace period need not wait
- * for subsequent online CPUs, and that quiescent-state forcing
- * will handle subsequent offline CPUs.
+ * rcu_node tree. Note that this new grace period need not wait for
+ * subsequent online CPUs, and that RCU hooks in the CPU offlining
+ * path, when combined with checks in this function, will handle CPUs
+ * that are currently going offline or that go offline later. Refer to
+ * RCU's Requirements documentation about hotplug requirements as well.
*/
rcu_state.gp_state = RCU_GP_ONOFF;
rcu_for_each_leaf_node(rnp) {
--
2.28.0.236.gb10cc79966-goog
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