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rcu: Eliminate local variable signaled from force_quiescent_state() 

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>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1262646550602-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul E. McKenney 2010-01-04 15:09:03 -08:00 committed by Ingo Molnar
parent 07079d5357
commit f3a8b5c6aa
1 changed files with 3 additions and 6 deletions
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9
kernel/rcutree.c
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@ -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;