From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu, patches@linaro.org
Subject: [PATCH tip/core/rcu 0/23] v2 Improvements to RT response on big systems and expedited functions
Date: Thu, 20 Sep 2012 11:47:51 -0700 [thread overview]
Message-ID: <20120920184751.GA18657@linux.vnet.ibm.com> (raw)
Hello!
This patch series contains additional improvements to latency for
large systems (beyond those in 3.6), along with improvements to
synchronize_rcu_expedited(). It also fixes one race introduced by the
latency improvements and another that was there to start with (but made
more probable by the latency improvements). These are in a single
series due to conflicts that would otherwise occur. The individual
patches are as follows:
1-6. Move RCU grace-period initialization and cleanup into a kthread:
1. Move RCU grace-period initialization into kthread.
2. Prevent initialization-time quiescent-state race.
3. Allow RCU grace-period initialization to be preempted.
4. Move RCU grace-period cleanup into kthread.
5. Allow RCU grace-period cleanup to be preempted.
6. Break up rcu_gp_kthread() into subfunctions.
7. Prevent offline CPUs from executing RCU core code.
8. Provide an OOM handler to allow lazy callbacks to be motivated
under memory pressure.
9. Segregate rcu_state fields to improve cache locality
(Courtesy of Dimitri Sivanich).
10-13. Move RCU grace-period forcing into a kthread.
10. Move quiescent-state forcing into kthread.
11. Allow RCU quiescent-state forcing to be preempted.
12. Adjust debugfs tracing for kthread-based quiescent-state
forcing.
13. Prevent force_quiescent_state() memory contention.
14. Control grace-period duration from sysfs.
15. Make rcutree module parameters visible in sysfs.
16. Fix day-zero grace-period initialization/cleanup race.
17. Add random PROVE_RCU_DELAY to provoke initalization races.
18. Adjust for unconditional ->completed assignment.
19. Eliminate signed overflow in synchronize_rcu_expedited().
20. Reduce synchronize_rcu_expedited() latency.
21. Simplify quiescent-state detection.
22. Correctly handle reconfiguring to larger leaf fanout in the
case of CONFIG_RCU_FANOUT_EXACT=y. (New in this posting.)
23. Shrink RCU when there is a smaller number of CPUs than the
kernel was built for (NR_CPUS < nr_cpu_ids) even when the
leaf fanout did not change. (New in this posting.)
Changes from v1 (https://lkml.org/lkml/2012/8/30/171):
o Incorporated feedback from that posting (thank you Peter, Josh,
and Lai!). This involves some serious rebasing, so the patch
numbers do not match v1.
o Added patches #22 and #23 above.
Thanx, Paul
b/Documentation/RCU/trace.txt | 43 -
b/Documentation/kernel-parameters.txt | 11
b/kernel/rcutree.c | 970 ++++++++++++++++++----------------
b/kernel/rcutree.h | 28
b/kernel/rcutree_plugin.h | 131 +++-
b/kernel/rcutree_trace.c | 15
6 files changed, 680 insertions(+), 518 deletions(-)
next reply other threads:[~2012-09-20 18:48 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-20 18:47 Paul E. McKenney [this message]
2012-09-20 18:47 ` [PATCH tip/core/rcu 01/23] rcu: Move RCU grace-period initialization into a kthread Paul E. McKenney
2012-09-20 18:47 ` [PATCH tip/core/rcu 02/23] rcu: Prevent initialization-time quiescent-state race Paul E. McKenney
2012-09-20 18:47 ` [PATCH tip/core/rcu 03/23] rcu: Allow RCU grace-period initialization to be preempted Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 04/23] rcu: Move RCU grace-period cleanup into kthread Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 05/23] rcu: Allow RCU grace-period cleanup to be preempted Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 06/23] rcu: Break up rcu_gp_kthread() into subfunctions Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 07/23] rcu: Prevent offline CPUs from executing RCU core code Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 08/23] rcu: Provide OOM handler to motivate lazy RCU callbacks Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 09/23] rcu: Segregate rcu_state fields to improve cache locality Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 10/23] rcu: Move quiescent-state forcing into kthread Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 11/23] rcu: Allow RCU quiescent-state forcing to be preempted Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 12/23] rcu: Adjust debugfs tracing for kthread-based quiescent-state forcing Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 13/23] rcu: Prevent force_quiescent_state() memory contention Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 14/23] rcu: Control grace-period duration from sysfs Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 15/23] rcu: Make rcutree module parameters visible in sysfs Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 16/23] rcu: Fix day-zero grace-period initialization/cleanup race Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 17/23] rcu: Add random PROVE_RCU_DELAY to grace-period initialization Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 18/23] rcu: Adjust for unconditional ->completed assignment Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 19/23] rcu: Eliminate signed overflow in synchronize_rcu_expedited() Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 20/23] rcu: Reduce synchronize_rcu_expedited() latency Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 21/23] rcu: Simplify quiescent-state detection Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 22/23] rcu: Handle unbalanced rcu_node configurations with few CPUs Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 23/23] rcu: Shrink RCU based on number of CPUs Paul E. McKenney
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