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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 RFC tip/core/rcu 06/14] rcu/nocb: Advance CBs after merge in rcutree_migrate_callbacks()
Date: Fri,  2 Aug 2019 08:14:53 -0700	[thread overview]
Message-ID: <20190802151501.13069-6-paulmck@linux.ibm.com> (raw)
In-Reply-To: <20190802151435.GA1081@linux.ibm.com>

The rcutree_migrate_callbacks() invokes rcu_advance_cbs() on both the
offlined CPU's ->cblist and that of the surviving CPU, then merges
them.  However, after the merge, and of the offlined CPU's callbacks
that were not ready to be invoked will no longer be associated with a
grace-period number.  This commit therefore invokes rcu_advance_cbs()
one more time on the merged ->cblist in order to assign a grace-period
number to these callbacks.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
---
 kernel/rcu/tree.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 457623100d12..3e89b5b83ea0 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3205,6 +3205,7 @@ 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);
+	needwake = needwake || rcu_advance_cbs(my_rnp, my_rdp);
 	rcu_segcblist_disable(&rdp->cblist);
 	WARN_ON_ONCE(rcu_segcblist_empty(&my_rdp->cblist) !=
 		     !rcu_segcblist_n_cbs(&my_rdp->cblist));
-- 
2.17.1


  parent reply	other threads:[~2019-08-02 15:15 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02 15:14 [PATCH tip/core/rcu 0/14] No-CBs bypass addition for v5.4 Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 01/14] rcu/nocb: Atomic ->len field in rcu_segcblist structure Paul E. McKenney
2019-08-04 14:50   ` Peter Zijlstra
2019-08-04 14:52     ` Peter Zijlstra
2019-08-04 18:45       ` Paul E. McKenney
2019-08-04 18:42     ` Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 02/14] rcu/nocb: Add bypass callback queueing Paul E. McKenney
2019-08-07  0:03   ` Joel Fernandes
2019-08-07  0:16     ` Joel Fernandes
2019-08-07  0:35     ` Paul E. McKenney
2019-08-07  0:40       ` Steven Rostedt
2019-08-07  1:17         ` Paul E. McKenney
2019-08-07  1:24           ` Steven Rostedt
2019-08-07  3:47             ` Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 03/14] rcu/nocb: EXP Check use and usefulness of ->nocb_lock_contended Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 04/14] rcu/nocb: Print no-CBs diagnostics when rcutorture writer unduly delayed Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 05/14] rcu/nocb: Avoid synchronous wakeup in __call_rcu_nocb_wake() Paul E. McKenney
2019-08-02 15:14 ` Paul E. McKenney [this message]
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 07/14] rcu/nocb: Reduce nocb_cb_wait() leaf rcu_node ->lock contention Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 08/14] rcu/nocb: Reduce __call_rcu_nocb_wake() " Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 09/14] rcu/nocb: Don't wake no-CBs GP kthread if timer posted under overload Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 10/14] rcu: Allow rcu_do_batch() to dynamically adjust batch sizes Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 11/14] EXP nohz: Add TICK_DEP_BIT_RCU Paul E. McKenney
2019-08-02 15:14 ` [PATCH RFC tip/core/rcu 12/14] rcu/nohz: Force on tick when invoking lots of callbacks Paul E. McKenney
2019-08-02 15:15 ` [PATCH RFC tip/core/rcu 13/14] rcutorture: Force on tick for readers and callback flooders Paul E. McKenney
2019-08-02 15:15 ` [PATCH RFC tip/core/rcu 14/14] rcu/nohz: Make multi_cpu_stop() enable tick on all online CPUs Paul E. McKenney
2019-08-04 14:43   ` Peter Zijlstra
2019-08-04 14:48     ` Peter Zijlstra
2019-08-04 18:41       ` Paul E. McKenney
2019-08-04 20:24         ` Paul E. McKenney
2019-08-05  4:19           ` Paul E. McKenney
2019-08-05  8:07             ` Peter Zijlstra
2019-08-05 14:47               ` Paul E. McKenney
2019-08-05  8:05         ` Peter Zijlstra
2019-08-05 14:54           ` Paul E. McKenney
2019-08-05 15:50             ` Peter Zijlstra
2019-08-05 17:48               ` Paul E. McKenney
2019-08-06 18:08                 ` Paul E. McKenney
2019-08-07 21:41                   ` Paul E. McKenney
2019-08-08 20:35                     ` Paul E. McKenney
2019-08-08 21:30                       ` Paul E. McKenney
2019-08-09 16:51                         ` Paul E. McKenney
2019-08-09 18:07                           ` Joel Fernandes
2019-08-09 18:39                             ` Paul E. McKenney
2019-08-12 21:02   ` Frederic Weisbecker
2019-08-12 23:23     ` Paul E. McKenney
2019-08-13  1:33       ` Joel Fernandes
2019-08-13 12:30       ` Frederic Weisbecker
2019-08-13 14:48         ` Paul E. McKenney
2019-08-14 17:55           ` Joel Fernandes
2019-08-14 22:05             ` Paul E. McKenney
2019-08-15 15:07               ` Joel Fernandes
2019-08-15 17:23                 ` Paul E. McKenney
2019-08-15 18:15                   ` Joel Fernandes
2019-08-15 18:39                     ` Paul E. McKenney
2019-08-15 19:42                       ` Joel Fernandes
2019-08-13 21:06       ` Paul E. McKenney

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