The following commit has been merged into the core/rcu branch of tip:
Commit-ID: 7ee880b7bf1dea88d0a472b775aebdb4fb6bf860
Gitweb: https://git.kernel.org/tip/7ee880b7bf1dea88d0a472b775aebdb4fb6bf860
Author: Wei Yang <richard.weiyang@xxxxxxxxx>
AuthorDate: Wed, 15 Apr 2020 22:26:55
Committer: Paul E. McKenney <paulmck@xxxxxxxxxx>
CommitterDate: Mon, 29 Jun 2020 11:58:49 -07:00
rcu: Initialize and destroy rcu_synchronize only when necessary
The __wait_rcu_gp() function unconditionally initializes and cleans up
each element of rs_array[], whether used or not. This is slightly
wasteful and rather confusing, so this commit skips both initialization
and cleanup for duplicate callback functions.
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
kernel/rcu/update.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 84843ad..f5a82e1 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -390,13 +390,14 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
might_sleep();
continue;
}
- init_rcu_head_on_stack(&rs_array[i].head);
- init_completion(&rs_array[i].completion);
for (j = 0; j < i; j++)
if (crcu_array[j] == crcu_array[i])
break;
- if (j == i)
+ if (j == i) {
+ init_rcu_head_on_stack(&rs_array[i].head);
+ init_completion(&rs_array[i].completion);
(crcu_array[i])(&rs_array[i].head, wakeme_after_rcu);
+ }
}
/* Wait for all callbacks to be invoked. */
@@ -407,9 +408,10 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
for (j = 0; j < i; j++)
if (crcu_array[j] == crcu_array[i])
break;
- if (j == i)
+ if (j == i) {
wait_for_completion(&rs_array[i].completion);
- destroy_rcu_head_on_stack(&rs_array[i].head);
+ destroy_rcu_head_on_stack(&rs_array[i].head);
+ }
}
}
EXPORT_SYMBOL_GPL(__wait_rcu_gp);
|