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Commit f3a8b5c6 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
Browse files

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: default avatarPaul 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: default avatarIngo Molnar <mingo@elte.hu>
parent 07079d53

kernel/rcutree.c

+3 −6
Original line number Original line Diff line number Diff line
@@ -1193,7 +1193,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) 
	unsigned long flags;

	unsigned long flags;

	long lastcomp;

	long lastcomp;

	struct rcu_node *rnp = rcu_get_root(rsp);

	struct rcu_node *rnp = rcu_get_root(rsp);

	u8 signaled;

	u8 forcenow;

	u8 forcenow;

	u8 gpdone;

	u8 gpdone;
@@ -1209,7 +1208,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) 
	rsp->n_force_qs++;

	rsp->n_force_qs++;

	spin_lock(&rnp->lock);  /* irqs already disabled */

	spin_lock(&rnp->lock);  /* irqs already disabled */

	lastcomp = rsp->gpnum - 1;

	lastcomp = rsp->gpnum - 1;

	signaled = rsp->signaled;

	rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;

	rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;

	if(!rcu_gp_in_progress(rsp)) {

	if(!rcu_gp_in_progress(rsp)) {

		rsp->n_force_qs_ngp++;

		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. */

		goto unlock_fqs_ret;  /* no GP in progress, time updated. */

	}

	}

	rsp->fqs_active = 1;

	rsp->fqs_active = 1;

	switch (signaled) {

	switch (rsp->signaled) {

	case RCU_GP_IDLE:

	case RCU_GP_IDLE:

	case RCU_GP_INIT:

	case RCU_GP_INIT:
@@ -1242,11 +1240,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) 
		/* Update state, record completion counter. */

		/* Update state, record completion counter. */

		forcenow = 0;

		forcenow = 0;

		if (lastcomp + 1 == rsp->gpnum &&

		if (lastcomp + 1 == rsp->gpnum &&

		    lastcomp == rsp->completed &&

		    lastcomp == rsp->completed) {

		    rsp->signaled == signaled) {

			forcenow = rsp->signaled == RCU_SAVE_COMPLETED;

			rsp->signaled = RCU_FORCE_QS;

			rsp->signaled = RCU_FORCE_QS;

			rsp->completed_fqs = lastcomp;

			rsp->completed_fqs = lastcomp;

			forcenow = signaled == RCU_SAVE_COMPLETED;

		}

		}

		if (!forcenow)

		if (!forcenow)

			break;

			break;