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

Nicholas Piggin npiggin at gmail.com
Thu Jul 2 17:48:33 AEST 2020


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

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 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



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