rcu-tasks: Don't delete holdouts within trc_wait_for_one_reader()

[ Upstream commit a9ab9cce9367a2cc02a3c7eb57a004dc0b8f380d ]

Invoking trc_del_holdout() from within trc_wait_for_one_reader() is
only a performance optimization because the RCU Tasks Trace grace-period
kthread will eventually do this within check_all_holdout_tasks_trace().
But it is not a particularly important performance optimization because
it only applies to the grace-period kthread, of which there is but one.
This commit therefore removes this invocation of trc_del_holdout() in
favor of the one in check_all_holdout_tasks_trace() in the grace-period
kthread.

Reported-by: "Xu, Yanfei" <yanfei.xu@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 208acb286ec28cb67cd3c3e14ea9072e09b32082..b338f514ee5aa996b0efb8a38d63055d62c9cade 100644 (file)
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -908,7 +908,6 @@ static void trc_wait_for_one_reader(struct task_struct *t,
        // The current task had better be in a quiescent state.
        if (t == current) {
                t->trc_reader_checked = true;
-               trc_del_holdout(t);
                WARN_ON_ONCE(t->trc_reader_nesting);
                return;
        }