From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: [GIT PULL rcu/urgent] Fixes for RCU regressions in 3.8 Date: Fri, 11 Jan 2013 08:08:13 -0800 Message-ID: <20130111160813.GA14503@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: paul.gortmaker@windriver.com, fweisbec@gmail.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org To: mingo@elte.hu Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org Hello, Ingo, Paul Gortmaker found some problems with no-CBs-CPU support in 3.8 mainline, and kindly supplied fixes. The first problem is soft-lockup complaints that can occur on systems running with no-CBs CPUs that have long periods of time where RCU is completely idle, which can happen on some embedded systems. The second problem is a documentation error for the "rcutree.rcu_nocb_poll" boot parameter. In this case, Paul Gortmaker (rightly) noted that the need for "rcutree." was inconsistent with the "rcu_nocbs=" boot parameter. The fix therefore to make the boot parameter named "rcu_nocb_poll". These problems only affect kernels built with the new CONFIG_RCU_NOCB_CPU kernel parameter, but still should be fixed. These fixes are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rcu/urgent Thanx, Paul ------------------> Paul Gortmaker (2): rcu: Prevent soft-lockup complaints about no-CBs CPUs rcu: Make rcu_nocb_poll an early_param instead of module_param Documentation/kernel-parameters.txt | 2 +- kernel/rcutree_plugin.h | 13 ++++++++++--- 2 files changed, 11 insertions(+), 4 deletions(-)