Commit 594aa597 authored May 25, 2020 by Uladzislau Rezki (Sony) Committed by Paul E. McKenney Jun 29, 2020

rcu/tree: Repeat the monitor if any free channel is busy



It is possible that one of the channels cannot be detached
because its free channel is busy and previously queued data
has not been processed yet. On the other hand, another
channel can be successfully detached causing the monitor
work to stop.

Prevent that by rescheduling the monitor work if there are
any channels in the pending state after a detach attempt.

Fixes: 34c88174 ("rcu: Support kfree_bulk() interface in kfree_rcu()")
Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

parent 4d291941

kernel/rcu/tree.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -3105,7 +3105,7 @@ static void kfree_rcu_work(struct work_struct *work)
		static inline bool queue_kfree_rcu_work(struct kfree_rcu_cpu *krcp)
		{
		struct kfree_rcu_cpu_work *krwp;
		bool queued = false;
		bool repeat = false;
		int i;

		lockdep_assert_held(&krcp->lock);
		@@ -3143,11 +3143,14 @@ static inline bool queue_kfree_rcu_work(struct kfree_rcu_cpu *krcp)
		* been detached following each other, one by one.
		*/
		queue_rcu_work(system_wq, &krwp->rcu_work);
		queued = true;
		}

		/* Repeat if any "free" corresponding channel is still busy. */
		if (krcp->bhead \|\| krcp->head)
		repeat = true;
		}

		return queued;
		return !repeat;
		}

		static inline void kfree_rcu_drain_unlock(struct kfree_rcu_cpu *krcp,

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