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| author | Paul E. McKenney <paulmck@linux.ibm.com> | 2018-11-28 19:37:42 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-01-26 00:28:24 +0100 |
| commit | 1de462ed85062df2ab6939eeee1625e767052907 (patch) | |
| tree | 95f4d4df0605d284c33d9926b810fd10287b2f30 /kernel/rcu | |
| parent | rcu: Rename and comment changes due to only one rcuo kthread per CPU (diff) | |
| download | linux-1de462ed85062df2ab6939eeee1625e767052907.tar.xz linux-1de462ed85062df2ab6939eeee1625e767052907.zip | |
rcu: Make expedited IPI handler return after handling critical section
During expedited RCU grace-period initialization, IPIs are sent to
all non-idle online CPUs. The IPI handler checks to see if the CPU is
in quiescent state, reporting one if so. This handler looks at three
different cases: (1) The CPU is not in an rcu_read_lock()-based critical
section, (2) The CPU is in the process of exiting an rcu_read_lock()-based
critical section, and (3) The CPU is in an rcu_read_lock()-based critical
section. In case (2), execution falls through into case (3).
This is harmless from a functionality viewpoint, but can result in
needless overhead during an improbable corner case. This commit therefore
adds the "return" statement needed to prevent fall-through.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree_exp.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 928fe5893a57..6d4eb4694b6f 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -697,6 +697,7 @@ static void sync_rcu_exp_handler(void *unused) WRITE_ONCE(t->rcu_read_unlock_special.b.exp_hint, true); } raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + return; } /* |