[PATCH 13/48] rcu: Add data structures for synchronize_rcu()

Uladzislau Rezki (Sony)
2024-05-07T09:35:47Z

The synchronize_rcu() call is going to be reworked, thus
this patch adds dedicated fields into the rcu_state structure.

Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
kernel/rcu/tree.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index df48160b3136..b942b9437438 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -315,6 +315,13 @@ do { \
__set_current_state(TASK_RUNNING); \
} while (0)

+#define SR_NORMAL_GP_WAIT_HEAD_MAX 5
+
+struct sr_wait_node {
+ atomic_t inuse;
+ struct llist_node node;
+};
+
/*
* RCU global state, including node hierarchy. This hierarchy is
* represented in "heap" form in a dense array. The root (first level)
@@ -400,6 +407,13 @@ struct rcu_state {
/* Synchronize offline with */
/* GP pre-initialization. */
int nocb_is_setup; /* nocb is setup from boot */
+
+ /* synchronize_rcu() part. */
+ struct llist_head srs_next; /* request a GP users. */
+ struct llist_node *srs_wait_tail; /* wait for GP users. */
+ struct llist_node *srs_done_tail; /* ready for GP users. */
+ struct sr_wait_node srs_wait_nodes[SR_NORMAL_GP_WAIT_HEAD_MAX];
+ struct work_struct srs_cleanup_work;
};

/* Values for rcu_state structure's gp_flags field. */
--
2.39.2