From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: linux-next: build failure after merge of the rcu tree Date: Thu, 7 Jan 2016 20:48:35 -0800 Message-ID: <20160108044835.GB3818@linux.vnet.ibm.com> References: <20160107195725.3a130b4d@canb.auug.org.au> <20160107180244.GR3818@linux.vnet.ibm.com> <20160108071932.060a9bcc@canb.auug.org.au> <20160107205220.GU3818@linux.vnet.ibm.com> <20160108013631.GA11410@fixme-laptop.cn.ibm.com> <20160108034157.GZ3818@linux.vnet.ibm.com> <20160108150850.1ec97e78@canb.auug.org.au> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from e31.co.us.ibm.com ([32.97.110.149]:44483 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753612AbcAHEsb (ORCPT ); Thu, 7 Jan 2016 23:48:31 -0500 Received: from localhost by e31.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 7 Jan 2016 21:48:30 -0700 Content-Disposition: inline In-Reply-To: <20160108150850.1ec97e78@canb.auug.org.au> Sender: linux-next-owner@vger.kernel.org List-ID: To: Stephen Rothwell Cc: Boqun Feng , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo , Christoph Lameter On Fri, Jan 08, 2016 at 03:08:50PM +1100, Stephen Rothwell wrote: > Hi Paul, > > On Thu, 7 Jan 2016 19:41:57 -0800 "Paul E. McKenney" wrote: > > > > Indeed, I suspect that SRCU might not be the only thing that would like > > static per-CPU variables. ;-) > > from include/linux/percpu-defs.h: > > * s390 and alpha modules require percpu variables to be defined as > * weak to force the compiler to generate GOT based external > * references for them. This is necessary because percpu sections > * will be located outside of the usually addressable area. > * > * This definition puts the following two extra restrictions when > * defining percpu variables. > * > * 1. The symbol must be globally unique, even the static ones. > * 2. Static percpu variables cannot be defined inside a function. > * > * Archs which need weak percpu definitions should define > * ARCH_NEEDS_WEAK_PER_CPU in asm/percpu.h when necessary. > * > * To ensure that the generic code observes the above two > * restrictions, if CONFIG_DEBUG_FORCE_WEAK_PER_CPU is set weak > * definition is used for all cases. > > so they can be static, but must be globally unique. Thank you for the tutorial! I have updated the patch to use a unique name for the srcu_struct added by rcuperf.c. Thanx, Paul