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);
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