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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
Subject: [PATCH tip/core/rcu 0/18] No-CBs cblist updates for v5.3-rc2
Date: Thu, 1 Aug 2019 16:07:44 -0700
Message-ID: <20190801230744.GA19115@linux.ibm.com> (raw)

Hello!

This series reduces memory footprint (RCU callbacks posted by no-CBs CPUs)
by causing the no-CBs CPUs to use the existing ->cblist segmented callback
list.  This allows these callbacks to take advantage of RCU grace periods
that were started by something other than the corresponding rcuog kthread:

1.	Use separate flag to indicate disabled ->cblist.

2.	Use separate flag to indicate offloaded ->cblist.

3.	Add checks for offloaded callback processing.

4.	Make rcutree_migrate_callbacks() start at leaf rcu_node structure.

5.	Check for deferred nocb wakeups before nohz_full early exit.

6.	Remove deferred wakeup checks for extended quiescent states.

7.	Allow lockless use of rcu_segcblist_restempty().

8.	Allow lockless use of rcu_segcblist_empty().

9.	Leave ->cblist enabled for no-CBs CPUs.

10.	Use rcu_segcblist for no-CBs CPUs.

11.	Remove obsolete nocb_head and nocb_tail fields.

12.	Remove obsolete nocb_q_count and nocb_q_count_lazy fields.

13.	Remove obsolete nocb_cb_tail and nocb_cb_head fields.

14.	Remove obsolete nocb_gp_head and nocb_gp_tail fields.

15.	Use build-time no-CBs check in rcu_do_batch().

16.	Use build-time no-CBs check in rcu_core().

17.	Use build-time no-CBs check in rcu_pending().

18.	Suppress uninitialized false-positive in nocb_gp_wait().

							Thanx, Paul

------------------------------------------------------------------------

 include/linux/rcu_segcblist.h |    2 
 include/trace/events/rcu.h    |    1 
 kernel/rcu/rcu_segcblist.c    |   64 +++-
 kernel/rcu/rcu_segcblist.h    |   16 -
 kernel/rcu/tree.c             |  188 +++++++------
 kernel/rcu/tree.h             |   29 --
 kernel/rcu/tree_plugin.h      |  588 ++++++++++++++----------------------------
 7 files changed, 374 insertions(+), 514 deletions(-)


             reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-01 23:07 Paul E. McKenney [this message]
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 ` [PATCH tip/core/rcu 12/18] rcu/nocb: Remove obsolete nocb_q_count and nocb_q_count_lazy fields Paul E. McKenney
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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