diff options
| author | Paul E. McKenney <paulmck@kernel.org> | 2022-05-26 16:12:51 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-06-20 09:22:27 -0700 |
| commit | 9ff86b4c443cc93bf3a9b624e3385e4114388e85 (patch) | |
| tree | abdd58db04c22386fdc60ae307915b3b9b0941ff /kernel/rcu/tasks.h | |
| parent | 550611269b153dc17b44fa2d692c30f628d1c65c (diff) | |
rcu-tasks: Make trc_read_check_handler() fetch ->trc_reader_nesting only once
This commit replaces the pair of READ_ONCE(t->trc_reader_nesting) calls
with a single such call and a local variable. This makes the code's
intent more clear.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: KP Singh <kpsingh@kernel.org>
Diffstat (limited to 'kernel/rcu/tasks.h')
| -rw-r--r-- | kernel/rcu/tasks.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 561d24f7f73c..8fe78a7fecaf 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1278,6 +1278,7 @@ static void trc_del_holdout(struct task_struct *t) /* IPI handler to check task state. */ static void trc_read_check_handler(void *t_in) { + int nesting; struct task_struct *t = current; struct task_struct *texp = t_in; @@ -1287,12 +1288,13 @@ static void trc_read_check_handler(void *t_in) // If the task is not in a read-side critical section, and // if this is the last reader, awaken the grace-period kthread. - if (likely(!READ_ONCE(t->trc_reader_nesting))) { + nesting = READ_ONCE(t->trc_reader_nesting); + if (likely(!nesting)) { rcu_trc_cmpxchg_need_qs(t, 0, TRC_NEED_QS_CHECKED); goto reset_ipi; } // If we are racing with an rcu_read_unlock_trace(), try again later. - if (unlikely(READ_ONCE(t->trc_reader_nesting) < 0)) + if (unlikely(nesting < 0)) goto reset_ipi; // Get here if the task is in a read-side critical section. Set |