From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753209Ab2H3SSo (ORCPT ); Thu, 30 Aug 2012 14:18:44 -0400 Received: from e35.co.us.ibm.com ([32.97.110.153]:46378 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752534Ab2H3SSn (ORCPT ); Thu, 30 Aug 2012 14:18:43 -0400 Date: Thu, 30 Aug 2012 11:18:11 -0700 From: "Paul E. McKenney" 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] Improvements to RT response on big systems and expedited functions Message-ID: <20120830181811.GA29154@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12083018-6148-0000-0000-000009162A42 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Allow RCU grace-period initialization to be preempted. 3. Move RCU grace-period cleanup into kthread. 4. Allow RCU grace-period cleanup to be preempted. 5. Prevent offline CPUs from executing RCU core code. 6. Break up rcu_gp_kthread() into subfunctions. 7. Provide an OOM handler to allow lazy callbacks to be motivated under memory pressure. 8. Segregate rcu_state fields to improve cache locality (Courtesy of Dimitri Sivanich). 9-12. Move RCU grace-period forcing into a kthread. 9. Move quiescent-state forcing into kthread. 10. Allow RCU quiescent-state forcing to be preempted. 11. Adjust debugfs tracing for kthread-based quiescent-state forcing. 12. Prevent force_quiescent_state() memory contention. 13. Control grace-period duration from sysfs. 14. Remove now-unused rcu_state fields. 15. Make rcutree module parameters visible in sysfs. 16. Prevent initialization-time quiescent-state race. 17. Fix day-zero grace-period initialization/cleanup race. 18. Add random PROVE_RCU_DELAY to provoke initalization races. 19. Adjust for unconditional ->completed assignment. 20. Remove callback acceleration from grace-period initialization due it no longer being safe. 21. Eliminate signed overflow in synchronize_rcu_expedited(). 22. Reduce synchronize_rcu_expedited() latency. 23. Simplify quiescent-state detection. Thanx, Paul ------------------------------------------------------------------------ b/Documentation/RCU/trace.txt | 43 - b/Documentation/kernel-parameters.txt | 11 b/kernel/rcutree.c | 191 +++++--- b/kernel/rcutree.h | 3 b/kernel/rcutree_plugin.h | 80 +++ b/kernel/rcutree_trace.c | 3 kernel/rcutree.c | 805 +++++++++++++++++----------------- kernel/rcutree.h | 25 - kernel/rcutree_plugin.h | 48 +- kernel/rcutree_trace.c | 12 10 files changed, 690 insertions(+), 531 deletions(-)