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Commit 7d9ab9b6 authored by Roman Gushchin's avatar Roman Gushchin Committed by Dennis Zhou
Browse files

percpu_ref: release percpu memory early without PERCPU_REF_ALLOW_REINIT 



Release percpu memory after finishing the switch to the atomic mode
if only PERCPU_REF_ALLOW_REINIT isn't set.

Signed-off-by: default avatarRoman Gushchin <guro@fb.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarDennis Zhou <dennis@kernel.org>
parent ddde2af7

include/linux/percpu-refcount.h

+1 −0
Original line number Diff line number Diff line
@@ -102,6 +102,7 @@ struct percpu_ref { 
	percpu_ref_func_t	*release;

	percpu_ref_func_t	*confirm_switch;

	bool			force_atomic:1;

	bool			allow_reinit:1;

	struct rcu_head		rcu;

};

lib/percpu-refcount.c

+11 −2
Original line number Diff line number Diff line
@@ -69,11 +69,14 @@ int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release, 
		return -ENOMEM;



	ref->force_atomic = flags & PERCPU_REF_INIT_ATOMIC;

	ref->allow_reinit = flags & PERCPU_REF_ALLOW_REINIT;



	if (flags & (PERCPU_REF_INIT_ATOMIC | PERCPU_REF_INIT_DEAD))

	if (flags & (PERCPU_REF_INIT_ATOMIC | PERCPU_REF_INIT_DEAD)) {

		ref->percpu_count_ptr |= __PERCPU_REF_ATOMIC;

	else

		ref->allow_reinit = true;

	} else {

		start_count += PERCPU_COUNT_BIAS;

	}



	if (flags & PERCPU_REF_INIT_DEAD)

		ref->percpu_count_ptr |= __PERCPU_REF_DEAD;
@@ -119,6 +122,9 @@ static void percpu_ref_call_confirm_rcu(struct rcu_head *rcu) 
	ref->confirm_switch = NULL;

	wake_up_all(&percpu_ref_switch_waitq);



	if (!ref->allow_reinit)

		percpu_ref_exit(ref);



	/* drop ref from percpu_ref_switch_to_atomic() */

	percpu_ref_put(ref);

}
@@ -194,6 +200,9 @@ static void __percpu_ref_switch_to_percpu(struct percpu_ref *ref) 
	if (!(ref->percpu_count_ptr & __PERCPU_REF_ATOMIC))

		return;



	if (WARN_ON_ONCE(!ref->allow_reinit))

		return;



	atomic_long_add(PERCPU_COUNT_BIAS, &ref->count);



	/*