Single-threaded processes don't need to issue barriers, since the thread's current CPU is the only one that matters.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> CC: Peter Zijlstra <pet...@infradead.org> CC: Paul E. McKenney <paul...@linux.vnet.ibm.com> CC: Boqun Feng <boqun.f...@gmail.com> CC: Andrew Hunter <a...@google.com> CC: Maged Michael <maged.mich...@gmail.com> CC: gro...@google.com CC: Avi Kivity <a...@scylladb.com> CC: Benjamin Herrenschmidt <b...@kernel.crashing.org> CC: Paul Mackerras <pau...@samba.org> CC: Michael Ellerman <m...@ellerman.id.au> CC: Dave Watson <davejwat...@fb.com> --- kernel/sched/membarrier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index a92fddc22747..7eec6914d2d2 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -39,7 +39,7 @@ static void membarrier_private_expedited(void) bool fallback = false; cpumask_var_t tmpmask; - if (num_online_cpus() == 1) + if (num_online_cpus() == 1 || get_nr_threads(current) == 1) return; /* -- 2.11.0