[PATCH v2 2/2] rcu/kvfree: Switch to expedited version in slow path

From: Uladzislau Rezki (Sony)
Date: Wed Sep 04 2024 - 10:40:02 EST


For a single argument and its slow path, switch to expedited
version of synchronize_rcu(). This version is considered to
be more faster, thus under a high memory pressure a slow path
becoms more efficient.

Note, latency-sensitive workloads should use rcutree.gp_normal=1,
which will make that synchronize_rcu_expedited() act like a regular
synchronize_rcu(), so no harm done to them.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
---
kernel/rcu/tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 182772494cb0..87a64fcffa7f 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3856,7 +3856,7 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr)
*/
if (!success) {
debug_rcu_head_unqueue((struct rcu_head *) ptr);
- cond_synchronize_rcu_full(&old_snap);
+ cond_synchronize_rcu_expedited_full(&old_snap);
kvfree(ptr);
}
}
--
2.39.2