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Subject[PATCH tip/core/rcu 12/18] rcu/nocb: Remove obsolete nocb_q_count and nocb_q_count_lazy fields
Date
This commit removes the obsolete nocb_q_count and nocb_q_count_lazy
fields, also removing rcu_get_n_cbs_nocb_cpu(), adjusting
rcu_get_n_cbs_cpu(), and making rcutree_migrate_callbacks() once again
disable the ->cblist fields of offline CPUs.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
---
kernel/rcu/tree.c | 6 +++---
kernel/rcu/tree.h | 3 ---
kernel/rcu/tree_plugin.h | 14 --------------
3 files changed, 3 insertions(+), 20 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 054418d2d960..e5f30b364276 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -210,10 +210,9 @@ static long rcu_get_n_cbs_cpu(int cpu)
{
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);

- if (rcu_segcblist_is_enabled(&rdp->cblist) &&
- !rcu_segcblist_is_offloaded(&rdp->cblist)) /* Online normal CPU? */
+ if (rcu_segcblist_is_enabled(&rdp->cblist))
return rcu_segcblist_n_cbs(&rdp->cblist);
- return rcu_get_n_cbs_nocb_cpu(rdp); /* Works for offline, too. */
+ return 0;
}

void rcu_softirq_qs(void)
@@ -3181,6 +3180,7 @@ void rcutree_migrate_callbacks(int cpu)
needwake = rcu_advance_cbs(my_rnp, rdp) ||
rcu_advance_cbs(my_rnp, my_rdp);
rcu_segcblist_merge(&my_rdp->cblist, &rdp->cblist);
+ rcu_segcblist_disable(&rdp->cblist);
WARN_ON_ONCE(rcu_segcblist_empty(&my_rdp->cblist) !=
!rcu_segcblist_n_cbs(&my_rdp->cblist));
if (rcu_segcblist_is_offloaded(&my_rdp->cblist)) {
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 74e3a4ab8095..d1df192272fb 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -194,8 +194,6 @@ struct rcu_data {

/* 5) Callback offloading. */
#ifdef CONFIG_RCU_NOCB_CPU
- atomic_long_t nocb_q_count; /* # CBs waiting for nocb */
- atomic_long_t nocb_q_count_lazy; /* invocation (all stages). */
struct rcu_head *nocb_cb_head; /* CBs ready to invoke. */
struct rcu_head **nocb_cb_tail;
struct swait_queue_head nocb_cb_wq; /* For nocb kthreads to sleep on. */
@@ -437,7 +435,6 @@ static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp,
#ifdef CONFIG_RCU_NOCB_CPU
static void __init rcu_organize_nocb_kthreads(void);
#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
-static unsigned long rcu_get_n_cbs_nocb_cpu(struct rcu_data *rdp);
static void rcu_bind_gp_kthread(void);
static bool rcu_nohz_full_cpu(void);
static void rcu_dynticks_task_enter(void);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 838e0caaf53a..458838c63a6c 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2040,15 +2040,6 @@ void rcu_bind_current_to_nocb(void)
}
EXPORT_SYMBOL_GPL(rcu_bind_current_to_nocb);

-/*
- * Return the number of RCU callbacks still queued from the specified
- * CPU, which must be a nocbs CPU.
- */
-static unsigned long rcu_get_n_cbs_nocb_cpu(struct rcu_data *rdp)
-{
- return atomic_long_read(&rdp->nocb_q_count);
-}
-
#else /* #ifdef CONFIG_RCU_NOCB_CPU */

/* No ->nocb_lock to acquire. */
@@ -2108,11 +2099,6 @@ static void __init rcu_spawn_nocb_kthreads(void)
{
}

-static unsigned long rcu_get_n_cbs_nocb_cpu(struct rcu_data *rdp)
-{
- return 0;
-}
-
#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */

/*
--
2.17.1
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