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Commit af446b70 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: ->signaled better named ->fqs_state 



The ->signaled field was named before complications in the form of
dyntick-idle mode and offlined CPUs.  These complications have required
that force_quiescent_state() be implemented as a state machine, instead
of simply unconditionally sending reschedule IPIs.  Therefore, this
commit renames ->signaled to ->fqs_state to catch up with the new
force_quiescent_state() reality.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent dc47ce90

kernel/rcutree.c

+8 −8
Original line number Diff line number Diff line
@@ -69,7 +69,7 @@ static struct lock_class_key rcu_node_class[NUM_RCU_LVLS]; 
		NUM_RCU_LVL_3, \

		NUM_RCU_LVL_4, /* == MAX_RCU_LVLS */ \

	}, \

	.signaled = RCU_GP_IDLE, \

	.fqs_state = RCU_GP_IDLE, \

	.gpnum = -300, \

	.completed = -300, \

	.onofflock = __RAW_SPIN_LOCK_UNLOCKED(&structname##_state.onofflock), \
@@ -866,8 +866,8 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) 
	/* Advance to a new grace period and initialize state. */

	rsp->gpnum++;

	trace_rcu_grace_period(rsp->name, rsp->gpnum, "start");

	WARN_ON_ONCE(rsp->signaled == RCU_GP_INIT);

	rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */

	WARN_ON_ONCE(rsp->fqs_state == RCU_GP_INIT);

	rsp->fqs_state = RCU_GP_INIT; /* Hold off force_quiescent_state. */

	rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;

	record_gp_stall_check_time(rsp);
@@ -877,7 +877,7 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) 
		rnp->qsmask = rnp->qsmaskinit;

		rnp->gpnum = rsp->gpnum;

		rnp->completed = rsp->completed;

		rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state OK. */

		rsp->fqs_state = RCU_SIGNAL_INIT; /* force_quiescent_state OK */

		rcu_start_gp_per_cpu(rsp, rnp, rdp);

		rcu_preempt_boost_start_gp(rnp);

		trace_rcu_grace_period_init(rsp->name, rnp->gpnum,
@@ -927,7 +927,7 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) 


	rnp = rcu_get_root(rsp);

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

	rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state now OK. */

	rsp->fqs_state = RCU_SIGNAL_INIT; /* force_quiescent_state now OK. */

	raw_spin_unlock(&rnp->lock);		/* irqs remain disabled. */

	raw_spin_unlock_irqrestore(&rsp->onofflock, flags);

}
@@ -991,7 +991,7 @@ static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) 


	rsp->completed = rsp->gpnum;  /* Declare the grace period complete. */

	trace_rcu_grace_period(rsp->name, rsp->completed, "end");

	rsp->signaled = RCU_GP_IDLE;

	rsp->fqs_state = RCU_GP_IDLE;

	rcu_start_gp(rsp, flags);  /* releases root node's rnp->lock. */

}
@@ -1457,7 +1457,7 @@ 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 (rsp->signaled) {

	switch (rsp->fqs_state) {

	case RCU_GP_IDLE:

	case RCU_GP_INIT:
@@ -1473,7 +1473,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) 
		force_qs_rnp(rsp, dyntick_save_progress_counter);

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

		if (rcu_gp_in_progress(rsp))

			rsp->signaled = RCU_FORCE_QS;

			rsp->fqs_state = RCU_FORCE_QS;

		break;



	case RCU_FORCE_QS:

kernel/rcutree.h

+2 −2
Original line number Diff line number Diff line
@@ -302,7 +302,7 @@ struct rcu_data { 
	struct rcu_state *rsp;

};



/* Values for signaled field in struct rcu_state. */

/* Values for fqs_state field in struct rcu_state. */

#define RCU_GP_IDLE		0	/* No grace period in progress. */

#define RCU_GP_INIT		1	/* Grace period being initialized. */

#define RCU_SAVE_DYNTICK	2	/* Need to scan dyntick state. */
@@ -361,7 +361,7 @@ struct rcu_state { 


	/* The following fields are guarded by the root rcu_node's lock. */



	u8	signaled ____cacheline_internodealigned_in_smp;

	u8	fqs_state ____cacheline_internodealigned_in_smp;

						/* Force QS state. */

	u8	fqs_active;			/* force_quiescent_state() */

						/*  is running. */

kernel/rcutree_trace.c

+1 −1
Original line number Diff line number Diff line
@@ -278,7 +278,7 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) 
	gpnum = rsp->gpnum;

	seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "

		      "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",

		   rsp->completed, gpnum, rsp->signaled,

		   rsp->completed, gpnum, rsp->fqs_state,

		   (long)(rsp->jiffies_force_qs - jiffies),

		   (int)(jiffies & 0xffff),

		   rsp->n_force_qs, rsp->n_force_qs_ngp,