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Subject[PATCH tip/core/rcu 04/11] rcu: eliminate local variable signaled from force_quiescent_state()
Date
From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Because the root rcu_node lock is held across entry to the switch
statement in force_quiescent_state(), it is no longer necessary
to snapshot rsp->signaled to a local variable. Eliminate both the
snapshotting and the local variable.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcutree.c | 9 +++------
1 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 41688ff..1d8cfb1 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1193,7 +1193,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
unsigned long flags;
long lastcomp;
struct rcu_node *rnp = rcu_get_root(rsp);
- u8 signaled;
u8 forcenow;
u8 gpdone;

@@ -1209,7 +1208,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
rsp->n_force_qs++;
spin_lock(&rnp->lock); /* irqs already disabled */
lastcomp = rsp->gpnum - 1;
- signaled = rsp->signaled;
rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
if(!rcu_gp_in_progress(rsp)) {
rsp->n_force_qs_ngp++;
@@ -1217,7 +1215,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
goto unlock_fqs_ret; /* no GP in progress, time updated. */
}
rsp->fqs_active = 1;
- switch (signaled) {
+ switch (rsp->signaled) {
case RCU_GP_IDLE:
case RCU_GP_INIT:

@@ -1242,11 +1240,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
/* Update state, record completion counter. */
forcenow = 0;
if (lastcomp + 1 == rsp->gpnum &&
- lastcomp == rsp->completed &&
- rsp->signaled == signaled) {
+ lastcomp == rsp->completed) {
+ forcenow = rsp->signaled == RCU_SAVE_COMPLETED;
rsp->signaled = RCU_FORCE_QS;
rsp->completed_fqs = lastcomp;
- forcenow = signaled == RCU_SAVE_COMPLETED;
}
if (!forcenow)
break;
--
1.5.2.5


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