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rcu: ->signaled better named ->fqs_state

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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>
This commit is contained in:
Paul E. McKenney
2011-09-10 21:54:08 -07:00
parent dc47ce90c3
commit af446b702c
3 changed files with 11 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
kernel/rcutree.c
View File

@@ -69,7 +69,7 @@ static struct lock_class_key rcu_node_class[NUM_RCU_LVLS];
NUM_RCU_LVL_3, \ NUM_RCU_LVL_3, \
NUM_RCU_LVL_4, /* == MAX_RCU_LVLS */ \ NUM_RCU_LVL_4, /* == MAX_RCU_LVLS */ \
}, \ }, \
.signaled = RCU_GP_IDLE, \ .fqs_state = RCU_GP_IDLE, \
.gpnum = -300, \ .gpnum = -300, \
.completed = -300, \ .completed = -300, \
.onofflock = __RAW_SPIN_LOCK_UNLOCKED(&structname##_state.onofflock), \ .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. */ /* Advance to a new grace period and initialize state. */
rsp->gpnum++; rsp->gpnum++;
trace_rcu_grace_period(rsp->name, rsp->gpnum, "start"); trace_rcu_grace_period(rsp->name, rsp->gpnum, "start");
WARN_ON_ONCE(rsp->signaled == RCU_GP_INIT); WARN_ON_ONCE(rsp->fqs_state == RCU_GP_INIT);
rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */ rsp->fqs_state = RCU_GP_INIT; /* Hold off force_quiescent_state. */
rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
record_gp_stall_check_time(rsp); 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->qsmask = rnp->qsmaskinit;
rnp->gpnum = rsp->gpnum; rnp->gpnum = rsp->gpnum;
rnp->completed = rsp->completed; 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_start_gp_per_cpu(rsp, rnp, rdp);
rcu_preempt_boost_start_gp(rnp); rcu_preempt_boost_start_gp(rnp);
trace_rcu_grace_period_init(rsp->name, rnp->gpnum, 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); rnp = rcu_get_root(rsp);
raw_spin_lock(&rnp->lock); /* irqs already disabled. */ 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(&rnp->lock); /* irqs remain disabled. */
raw_spin_unlock_irqrestore(&rsp->onofflock, flags); 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. */ rsp->completed = rsp->gpnum; /* Declare the grace period complete. */
trace_rcu_grace_period(rsp->name, rsp->completed, "end"); 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. */ 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. */ goto unlock_fqs_ret; /* no GP in progress, time updated. */
} }
rsp->fqs_active = 1; rsp->fqs_active = 1;
switch (rsp->signaled) { switch (rsp->fqs_state) {
case RCU_GP_IDLE: case RCU_GP_IDLE:
case RCU_GP_INIT: 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); force_qs_rnp(rsp, dyntick_save_progress_counter);
raw_spin_lock(&rnp->lock); /* irqs already disabled */ raw_spin_lock(&rnp->lock); /* irqs already disabled */
if (rcu_gp_in_progress(rsp)) if (rcu_gp_in_progress(rsp))
rsp->signaled = RCU_FORCE_QS; rsp->fqs_state = RCU_FORCE_QS;
break; break;
case RCU_FORCE_QS: case RCU_FORCE_QS:

4
kernel/rcutree.h
View File

@@ -302,7 +302,7 @@ struct rcu_data {
struct rcu_state *rsp; 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_IDLE 0 /* No grace period in progress. */
#define RCU_GP_INIT 1 /* Grace period being initialized. */ #define RCU_GP_INIT 1 /* Grace period being initialized. */
#define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */ #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. */ /* 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. */ /* Force QS state. */
u8 fqs_active; /* force_quiescent_state() */ u8 fqs_active; /* force_quiescent_state() */
/* is running. */ /* is running. */

2
kernel/rcutree_trace.c
View File

@@ -278,7 +278,7 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
gpnum = rsp->gpnum; gpnum = rsp->gpnum;
seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x " seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "
"nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n", "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), (long)(rsp->jiffies_force_qs - jiffies),
(int)(jiffies & 0xffff), (int)(jiffies & 0xffff),
rsp->n_force_qs, rsp->n_force_qs_ngp, rsp->n_force_qs, rsp->n_force_qs_ngp,