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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 6b76d81..5d0b55a 100644 (file)
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -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:

diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 849ce9e..517f2f8 100644 (file)
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -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. */

diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
index 9feffa4..59c7bee 100644 (file)
--- a/kernel/rcutree_trace.c
+++ b/kernel/rcutree_trace.c
@@ -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,