2012-11-09 02:21:40

by Shan Wei

Subject: [PATCH v3 6/9] rcu: use __this_cpu_read helper instead of per_cpu_ptr(p, raw_smp_processor_id())

From: Shan Wei <[email protected]>

Signed-off-by: Shan Wei <[email protected]>
---
no changes vs v2.
---
kernel/rcutree.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 74df86b..441b945 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1960,7 +1960,7 @@ static void force_quiescent_state(struct rcu_state *rsp)
struct rcu_node *rnp_old = NULL;

/* Funnel through hierarchy to reduce memory contention. */
- rnp = per_cpu_ptr(rsp->rda, raw_smp_processor_id())->mynode;
+ rnp = __this_cpu_read(rsp->rda->mynode);
for (; rnp != NULL; rnp = rnp->parent) {
ret = (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) ||
!raw_spin_trylock(&rnp->fqslock);
--
1.7.1

2012-11-09 20:14:06

by Christoph Lameter (Ampere)

Subject: Re: [PATCH v3 6/9] rcu: use __this_cpu_read helper instead of per_cpu_ptr(p, raw_smp_processor_id())

On Fri, 9 Nov 2012, Shan Wei wrote:

> /* Funnel through hierarchy to reduce memory contention. */
> - rnp = per_cpu_ptr(rsp->rda, raw_smp_processor_id())->mynode;
> + rnp = __this_cpu_read(rsp->rda->mynode);
> for (; rnp != NULL; rnp = rnp->parent) {

Acked-by: Christoph Lameter <[email protected]>