percpu-rwsem: use synchronize_sched_expedited
Use synchronize_sched_expedited() instead of synchronize_sched()
to improve mount speed.
This patch improves mount time from 0.500s to 0.013s for Jeff's
test-case.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-and-tested-by: Jeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index 250a4ac..bd1e860 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -13,7 +13,7 @@
};
#define light_mb() barrier()
-#define heavy_mb() synchronize_sched()
+#define heavy_mb() synchronize_sched_expedited()
static inline void percpu_down_read(struct percpu_rw_semaphore *p)
{
@@ -51,7 +51,7 @@
{
mutex_lock(&p->mtx);
p->locked = true;
- synchronize_sched(); /* make sure that all readers exit the rcu_read_lock_sched region */
+ synchronize_sched_expedited(); /* make sure that all readers exit the rcu_read_lock_sched region */
while (__percpu_count(p->counters))
msleep(1);
heavy_mb(); /* C, between read of p->counter and write to data, paired with B */