[PATCH 2/8] powerpc/pseries: use smp_rmb() in H_CONFER spin yield

From: Nicholas Piggin
Date: Thu Jul 02 2020 - 03:49:08 EST


There is no need for rmb(), this allows faster lwsync here.

Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/powerpc/lib/locks.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c
index 6440d5943c00..47a530de733e 100644
--- a/arch/powerpc/lib/locks.c
+++ b/arch/powerpc/lib/locks.c
@@ -30,7 +30,7 @@ void splpar_spin_yield(arch_spinlock_t *lock)
yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count);
if ((yield_count & 1) == 0)
return; /* virtual cpu is currently running */
- rmb();
+ smp_rmb();
if (lock->slock != lock_value)
return; /* something has changed */
plpar_hcall_norets(H_CONFER,
@@ -56,7 +56,7 @@ void splpar_rw_yield(arch_rwlock_t *rw)
yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count);
if ((yield_count & 1) == 0)
return; /* virtual cpu is currently running */
- rmb();
+ smp_rmb();
if (rw->lock != lock_value)
return; /* something has changed */
plpar_hcall_norets(H_CONFER,
--
2.23.0