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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-01-05 00:09:03 +0100
committerIngo Molnar <mingo@elte.hu>2010-01-13 09:06:02 +0100
commitf3a8b5c6aa543bd87764418d63632eb65b80e2f6 (patch)
treec579ced57838ee4f0504c5c295d283b37636e747 /kernel/rcutree.c
parentrcu: Prohibit starting new grace periods while forcing quiescent states (diff)
downloadlinux-f3a8b5c6aa543bd87764418d63632eb65b80e2f6.tar.xz
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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>
Diffstat (limited to 'kernel/rcutree.c')
-rw-r--r--kernel/rcutree.c9
1 files changed, 3 insertions, 6 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 41688ff60e07..1d8cfb1711fd 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;