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rcu/nocb: Remove obsolete nocb_q_count and nocb_q_count_lazy fields

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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>
This commit is contained in:
Paul E. McKenney 2019-05-21 08:28:41 -07:00
parent e7f4c5b399
commit c035280f17
3 changed files with 3 additions and 20 deletions
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6
kernel/rcu/tree.c
View File

@ -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)) {

3
kernel/rcu/tree.h
View File

@ -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);

14
kernel/rcu/tree_plugin.h
View File

@ -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 */
/*