Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
authored by
Mikulas Patocka
and committed by
Linus Torvalds
4b05a1c7
e23739b4
+2
-2
+2
-2
include/linux/percpu-rwsem.h
+2
-2
include/linux/percpu-rwsem.h
···
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};
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#define light_mb() barrier()
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-
#define heavy_mb() synchronize_sched()
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+
#define heavy_mb() synchronize_sched_expedited()
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static inline void percpu_down_read(struct percpu_rw_semaphore *p)
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{
···
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{
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mutex_lock(&p->mtx);
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p->locked = true;
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-
synchronize_sched(); /* make sure that all readers exit the rcu_read_lock_sched region */
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+
synchronize_sched_expedited(); /* make sure that all readers exit the rcu_read_lock_sched region */
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while (__percpu_count(p->counters))
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msleep(1);
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heavy_mb(); /* C, between read of p->counter and write to data, paired with B */