diff mbox series

[08/20] srcu: Move ->lock initialization after srcu_usage allocation

Message ID 20230330224726.662344-8-paulmck@kernel.org (mailing list archive)
State Accepted
Commit 0839ade94bdef395bab02b3a579416c112062026
Headers show
Series Further shrink srcu_struct to promote cache locality | expand

Commit Message

Paul E. McKenney March 30, 2023, 10:47 p.m. UTC 
Currently, both __init_srcu_struct() in CONFIG_DEBUG_LOCK_ALLOC=y kernels
and init_srcu_struct() in CONFIG_DEBUG_LOCK_ALLOC=n kernel initialize
the srcu_struct structure's ->lock before the srcu_usage structure has
been allocated.  This of course prevents the ->lock from being moved
to the srcu_usage structure, so this commit moves the initialization
into the init_srcu_struct_fields() after the srcu_usage structure has
been allocated.

Cc: Christoph Hellwig <hch@lst.de>
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
Tested-by: "Zhang, Qiang1" <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/srcutree.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 1814f3bfc219..c2a024a60f1a 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -240,6 +240,8 @@  static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
 		ssp->srcu_sup = kzalloc(sizeof(*ssp->srcu_sup), GFP_KERNEL);
 	if (!ssp->srcu_sup)
 		return -ENOMEM;
+	if (!is_static)
+		spin_lock_init(&ACCESS_PRIVATE(ssp, lock));
 	ssp->srcu_sup->srcu_size_state = SRCU_SIZE_SMALL;
 	ssp->srcu_sup->node = NULL;
 	mutex_init(&ssp->srcu_sup->srcu_cb_mutex);
@@ -285,7 +287,6 @@  int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
 	/* Don't re-initialize a lock while it is held. */
 	debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));
 	lockdep_init_map(&ssp->dep_map, name, key, 0);
-	spin_lock_init(&ACCESS_PRIVATE(ssp, lock));
 	return init_srcu_struct_fields(ssp, false);
 }
 EXPORT_SYMBOL_GPL(__init_srcu_struct);
@@ -302,7 +303,6 @@  EXPORT_SYMBOL_GPL(__init_srcu_struct);
  */
 int init_srcu_struct(struct srcu_struct *ssp)
 {
-	spin_lock_init(&ACCESS_PRIVATE(ssp, lock));
 	return init_srcu_struct_fields(ssp, false);
 }
 EXPORT_SYMBOL_GPL(init_srcu_struct);