From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755140AbbAGRc2 (ORCPT ); Wed, 7 Jan 2015 12:32:28 -0500 Received: from e34.co.us.ibm.com ([32.97.110.152]:50236 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755117AbbAGRcZ (ORCPT ); Wed, 7 Jan 2015 12:32:25 -0500 Date: Wed, 7 Jan 2015 09:32:15 -0800 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, laijs@cn.fujitsu.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, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com Subject: [PATCH tip/core/rcu 0/14] Preemptible-RCU updates for 3.20 Message-ID: <20150107173215.GA897@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-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15010717-0017-0000-0000-000007BD7B61 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! This series fixes some problems in preemptible RCU. 1. Protect rcu_boost() lockless accesses with ACCESS_ONCE(). 2-11. Fix a low-probability long-standing bug in preemptible RCU that could occur in systems with more than 16 CPUs, but only if a full bank of 16 CPUs (as in 0-15, 16-31, 32-47, ...) was taken offline. See http://paulmck.livejournal.com/37782.html for more details. 12. Revert old commit that worked around an rt_mutex bug. This old commit could cause priority inversion, and the rt_mutex bug has long since been fixed. Courtesy of Lai Jiangshan. 13. Simplify grace-period code, enabled by 2-11 above. 14. Remove redundant RCU callback list initialization. Thanx, Paul ------------------------------------------------------------------------ b/kernel/rcu/tree.c | 115 +++++++++++++------------- b/kernel/rcu/tree.h | 24 ----- b/kernel/rcu/tree_plugin.h | 196 ++++++++++----------------------------------- 3 files changed, 102 insertions(+), 233 deletions(-)