From: "Paul E. McKenney" <paulmck@linux.ibm.com>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@linux.ibm.com>
Subject: [PATCH tip/core/rcu 12/18] rcu/nocb: Remove obsolete nocb_q_count and nocb_q_count_lazy fields
Date: Thu, 1 Aug 2019 16:08:04 -0700 [thread overview]
Message-ID: <20190801230810.21570-12-paulmck@linux.ibm.com> (raw)
In-Reply-To: <20190801230744.GA19115@linux.ibm.com>
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
next prev parent reply other threads:[~2019-08-01 23:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 23:07 [PATCH tip/core/rcu 0/18] No-CBs cblist updates for v5.3-rc2 Paul E. McKenney
2019-08-01 23:07 ` [PATCH tip/core/rcu 01/18] rcu/nocb: Use separate flag to indicate disabled ->cblist Paul E. McKenney
2019-08-01 23:07 ` [PATCH tip/core/rcu 02/18] rcu/nocb: Use separate flag to indicate offloaded ->cblist Paul E. McKenney
2019-08-01 23:07 ` [PATCH tip/core/rcu 03/18] rcu/nocb: Add checks for offloaded callback processing Paul E. McKenney
2019-08-01 23:07 ` [PATCH tip/core/rcu 04/18] rcu/nocb: Make rcutree_migrate_callbacks() start at leaf rcu_node structure Paul E. McKenney
2019-08-01 23:07 ` [PATCH tip/core/rcu 05/18] rcu/nocb: Check for deferred nocb wakeups before nohz_full early exit Paul E. McKenney
2019-08-01 23:07 ` [PATCH tip/core/rcu 06/18] rcu/nocb: Remove deferred wakeup checks for extended quiescent states Paul E. McKenney
2019-08-01 23:07 ` [PATCH tip/core/rcu 07/18] rcu/nocb: Allow lockless use of rcu_segcblist_restempty() Paul E. McKenney
2019-08-01 23:08 ` [PATCH tip/core/rcu 08/18] rcu/nocb: Allow lockless use of rcu_segcblist_empty() Paul E. McKenney
2019-08-01 23:08 ` [PATCH tip/core/rcu 09/18] rcu/nocb: Leave ->cblist enabled for no-CBs CPUs Paul E. McKenney
2019-08-01 23:08 ` [PATCH tip/core/rcu 10/18] rcu/nocb: Use rcu_segcblist " Paul E. McKenney
2019-08-01 23:08 ` [PATCH tip/core/rcu 11/18] rcu/nocb: Remove obsolete nocb_head and nocb_tail fields Paul E. McKenney
2019-08-01 23:08 ` Paul E. McKenney [this message]
2019-08-01 23:08 ` [PATCH tip/core/rcu 13/18] rcu/nocb: Remove obsolete nocb_cb_tail and nocb_cb_head fields Paul E. McKenney
2019-08-01 23:08 ` [PATCH tip/core/rcu 14/18] rcu/nocb: Remove obsolete nocb_gp_head and nocb_gp_tail fields Paul E. McKenney
2019-08-01 23:08 ` [PATCH tip/core/rcu 15/18] rcu/nocb: Use build-time no-CBs check in rcu_do_batch() Paul E. McKenney
2019-08-01 23:08 ` [PATCH tip/core/rcu 16/18] rcu/nocb: Use build-time no-CBs check in rcu_core() Paul E. McKenney
2019-08-01 23:08 ` [PATCH tip/core/rcu 17/18] rcu/nocb: Use build-time no-CBs check in rcu_pending() Paul E. McKenney
2019-08-01 23:08 ` [PATCH tip/core/rcu 18/18] rcu/nocb: Suppress uninitialized false-positive in nocb_gp_wait() Paul E. McKenney
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