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Message-Id: <1444148977-14108-2-git-send-email-paulmck@linux.vnet.ibm.com>
Date: Tue, 6 Oct 2015 09:29:21 -0700
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com,
akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
dvhart@...ux.intel.com, fweisbec@...il.com, oleg@...hat.com,
bobby.prani@...il.com,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 02/18] rcu: Move rcu_report_exp_rnp() to allow consolidation
This is a nearly pure code-movement commit, moving rcu_report_exp_rnp(),
sync_rcu_preempt_exp_done(), and rcu_preempted_readers_exp() so
that later commits can make synchronize_sched_expedited() use them.
The non-code-movement portion of this commit tags rcu_report_exp_rnp()
as __maybe_unused to avoid build errors when CONFIG_PREEMPT=n.
Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
kernel/rcu/tree.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++
kernel/rcu/tree_plugin.h | 66 ------------------------------------------------
2 files changed, 66 insertions(+), 66 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 53d66ebb4811..59af27d8bc6a 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3379,6 +3379,72 @@ static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)
return rcu_seq_done(&rsp->expedited_sequence, s);
}
+/*
+ * Return non-zero if there are any tasks in RCU read-side critical
+ * sections blocking the current preemptible-RCU expedited grace period.
+ * If there is no preemptible-RCU expedited grace period currently in
+ * progress, returns zero unconditionally.
+ */
+static int rcu_preempted_readers_exp(struct rcu_node *rnp)
+{
+ return rnp->exp_tasks != NULL;
+}
+
+/*
+ * return non-zero if there is no RCU expedited grace period in progress
+ * for the specified rcu_node structure, in other words, if all CPUs and
+ * tasks covered by the specified rcu_node structure have done their bit
+ * for the current expedited grace period. Works only for preemptible
+ * RCU -- other RCU implementation use other means.
+ *
+ * Caller must hold the root rcu_node's exp_funnel_mutex.
+ */
+static int sync_rcu_preempt_exp_done(struct rcu_node *rnp)
+{
+ return !rcu_preempted_readers_exp(rnp) &&
+ READ_ONCE(rnp->expmask) == 0;
+}
+
+/*
+ * Report the exit from RCU read-side critical section for the last task
+ * that queued itself during or before the current expedited preemptible-RCU
+ * grace period. This event is reported either to the rcu_node structure on
+ * which the task was queued or to one of that rcu_node structure's ancestors,
+ * recursively up the tree. (Calm down, calm down, we do the recursion
+ * iteratively!)
+ *
+ * Caller must hold the root rcu_node's exp_funnel_mutex.
+ */
+static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp,
+ struct rcu_node *rnp, bool wake)
+{
+ unsigned long flags;
+ unsigned long mask;
+
+ raw_spin_lock_irqsave(&rnp->lock, flags);
+ smp_mb__after_unlock_lock();
+ for (;;) {
+ if (!sync_rcu_preempt_exp_done(rnp)) {
+ raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ break;
+ }
+ if (rnp->parent == NULL) {
+ raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ if (wake) {
+ smp_mb(); /* EGP done before wake_up(). */
+ wake_up(&rsp->expedited_wq);
+ }
+ break;
+ }
+ mask = rnp->grpmask;
+ raw_spin_unlock(&rnp->lock); /* irqs remain disabled */
+ rnp = rnp->parent;
+ raw_spin_lock(&rnp->lock); /* irqs already disabled */
+ smp_mb__after_unlock_lock();
+ rnp->expmask &= ~mask;
+ }
+}
+
/* Common code for synchronize_{rcu,sched}_expedited() work-done checking. */
static bool sync_exp_work_done(struct rcu_state *rsp, struct rcu_node *rnp,
struct rcu_data *rdp,
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 72df006de798..e73be8539978 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -536,72 +536,6 @@ void synchronize_rcu(void)
EXPORT_SYMBOL_GPL(synchronize_rcu);
/*
- * Return non-zero if there are any tasks in RCU read-side critical
- * sections blocking the current preemptible-RCU expedited grace period.
- * If there is no preemptible-RCU expedited grace period currently in
- * progress, returns zero unconditionally.
- */
-static int rcu_preempted_readers_exp(struct rcu_node *rnp)
-{
- return rnp->exp_tasks != NULL;
-}
-
-/*
- * return non-zero if there is no RCU expedited grace period in progress
- * for the specified rcu_node structure, in other words, if all CPUs and
- * tasks covered by the specified rcu_node structure have done their bit
- * for the current expedited grace period. Works only for preemptible
- * RCU -- other RCU implementation use other means.
- *
- * Caller must hold the root rcu_node's exp_funnel_mutex.
- */
-static int sync_rcu_preempt_exp_done(struct rcu_node *rnp)
-{
- return !rcu_preempted_readers_exp(rnp) &&
- READ_ONCE(rnp->expmask) == 0;
-}
-
-/*
- * Report the exit from RCU read-side critical section for the last task
- * that queued itself during or before the current expedited preemptible-RCU
- * grace period. This event is reported either to the rcu_node structure on
- * which the task was queued or to one of that rcu_node structure's ancestors,
- * recursively up the tree. (Calm down, calm down, we do the recursion
- * iteratively!)
- *
- * Caller must hold the root rcu_node's exp_funnel_mutex.
- */
-static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
- bool wake)
-{
- unsigned long flags;
- unsigned long mask;
-
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
- for (;;) {
- if (!sync_rcu_preempt_exp_done(rnp)) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
- break;
- }
- if (rnp->parent == NULL) {
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
- if (wake) {
- smp_mb(); /* EGP done before wake_up(). */
- wake_up(&rsp->expedited_wq);
- }
- break;
- }
- mask = rnp->grpmask;
- raw_spin_unlock(&rnp->lock); /* irqs remain disabled */
- rnp = rnp->parent;
- raw_spin_lock(&rnp->lock); /* irqs already disabled */
- smp_mb__after_unlock_lock();
- rnp->expmask &= ~mask;
- }
-}
-
-/*
* Snapshot the tasks blocking the newly started preemptible-RCU expedited
* grace period for the specified rcu_node structure, phase 1. If there
* are such tasks, set the ->expmask bits up the rcu_node tree and also
--
2.5.2
--
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