Commit 574dc1a7 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

srcu: Move ->srcu_cb_mutex from srcu_struct to srcu_usage 



This commit moves the ->srcu_cb_mutex field from the srcu_struct structure
to the srcu_usage structure to reduce the size of the former in order
to improve cache locality.

Suggested-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarSachin Sant <sachinp@linux.ibm.com>
Tested-by: default avatar"Zhang, Qiang1" <qiang1.zhang@intel.com>
Tested-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent a0d8cbd3

include/linux/srcutree.h

+1 −1
Original line number Diff line number Diff line
@@ -65,13 +65,13 @@ struct srcu_usage { 
	struct srcu_node *level[RCU_NUM_LVLS + 1];

						/* First node at each level. */

	int srcu_size_state;			/* Small-to-big transition state. */

	struct mutex srcu_cb_mutex;		/* Serialize CB preparation. */

};



/*

 * Per-SRCU-domain structure, similar in function to rcu_state.

 */

struct srcu_struct {

	struct mutex srcu_cb_mutex;		/* Serialize CB preparation. */

	spinlock_t __private lock;		/* Protect counters and size state. */

	struct mutex srcu_gp_mutex;		/* Serialize GP work. */

	unsigned int srcu_idx;			/* Current rdr array element. */

kernel/rcu/srcutree.c

+3 −3
Original line number Diff line number Diff line
@@ -242,7 +242,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static) 
		return -ENOMEM;

	ssp->srcu_sup->srcu_size_state = SRCU_SIZE_SMALL;

	ssp->srcu_sup->node = NULL;

	mutex_init(&ssp->srcu_cb_mutex);

	mutex_init(&ssp->srcu_sup->srcu_cb_mutex);

	mutex_init(&ssp->srcu_gp_mutex);

	ssp->srcu_idx = 0;

	ssp->srcu_gp_seq = 0;
@@ -861,7 +861,7 @@ static void srcu_gp_end(struct srcu_struct *ssp) 
	int ss_state;



	/* Prevent more than one additional grace period. */

	mutex_lock(&ssp->srcu_cb_mutex);

	mutex_lock(&ssp->srcu_sup->srcu_cb_mutex);



	/* End the current grace period. */

	spin_lock_irq_rcu_node(ssp);
@@ -921,7 +921,7 @@ static void srcu_gp_end(struct srcu_struct *ssp) 
		}



	/* Callback initiation done, allow grace periods after next. */

	mutex_unlock(&ssp->srcu_cb_mutex);

	mutex_unlock(&ssp->srcu_sup->srcu_cb_mutex);



	/* Start a new grace period if needed. */

	spin_lock_irq_rcu_node(ssp);