From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: linux-next: manual merge of the rcu tree with the tip tree Date: Mon, 18 Jul 2016 20:00:45 -0700 Message-ID: <20160719030045.GR7094@linux.vnet.ibm.com> References: <20160718152628.312b3e43@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 mx0a-001b2d01.pphosted.com ([148.163.156.1]:49197 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752187AbcGSDAd (ORCPT ); Mon, 18 Jul 2016 23:00:33 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u6J2wfAg128198 for ; Mon, 18 Jul 2016 23:00:32 -0400 Received: from e18.ny.us.ibm.com (e18.ny.us.ibm.com [129.33.205.208]) by mx0a-001b2d01.pphosted.com with ESMTP id 2495r91cph-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 18 Jul 2016 23:00:32 -0400 Received: from localhost by e18.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 18 Jul 2016 23:00:30 -0400 Content-Disposition: inline In-Reply-To: <20160718152628.312b3e43@canb.auug.org.au> Sender: linux-next-owner@vger.kernel.org List-ID: To: Stephen Rothwell Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Peter Zijlstra , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, Anna-Maria Gleixner On Mon, Jul 18, 2016 at 03:26:28PM +1000, Stephen Rothwell wrote: > Hi Paul, > > Today's linux-next merge of the rcu tree got a conflict in: > > kernel/rcu/tree.c > > between commit: > > 4df8374254ea ("rcu: Convert rcutree to hotplug state machine") > > from the tip tree and commit: > > 2a84cde733b0 ("rcu: Exact CPU-online tracking for RCU") > > from the rcu tree. > > I fixed it up (see below) and can carry the fix as necessary. This > is now fixed as far as linux-next is concerned, but any non trivial > conflicts should be mentioned to your upstream maintainer when your tree > is submitted for merging. You may also want to consider cooperating > with the maintainer of the conflicting tree to minimise any particularly > complex conflicts. Ah, that is in -tip now? Easier to test, then! Thank you, the patch looks good at first glance, but will beat it up a bit. Thanx, Paul > -- > Cheers, > Stephen Rothwell > > diff --cc kernel/rcu/tree.c > index e5164deb51e1,5663d1e899d3..000000000000 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@@ -3812,54 -3809,34 +3809,80 @@@ int rcutree_prepare_cpu(unsigned int cp > > for_each_rcu_flavor(rsp) > rcu_init_percpu_data(cpu, rsp); > + > + rcu_prepare_kthreads(cpu); > + rcu_spawn_all_nocb_kthreads(cpu); > + > + return 0; > +} > + > +static void rcutree_affinity_setting(unsigned int cpu, int outgoing) > +{ > + struct rcu_data *rdp = per_cpu_ptr(rcu_state_p->rda, cpu); > + > + rcu_boost_kthread_setaffinity(rdp->mynode, outgoing); > +} > + > +int rcutree_online_cpu(unsigned int cpu) > +{ > + sync_sched_exp_online_cleanup(cpu); > + rcutree_affinity_setting(cpu, -1); > + return 0; > +} > + > +int rcutree_offline_cpu(unsigned int cpu) > +{ > + rcutree_affinity_setting(cpu, cpu); > + return 0; > +} > + > + > +int rcutree_dying_cpu(unsigned int cpu) > +{ > + struct rcu_state *rsp; > + > + for_each_rcu_flavor(rsp) > + rcu_cleanup_dying_cpu(rsp); > + return 0; > +} > + > +int rcutree_dead_cpu(unsigned int cpu) > +{ > + struct rcu_state *rsp; > + > + for_each_rcu_flavor(rsp) { > + rcu_cleanup_dead_cpu(cpu, rsp); > + do_nocb_deferred_wakeup(per_cpu_ptr(rsp->rda, cpu)); > + } > + return 0; > } > > + /* > + * Mark the specified CPU as being online so that subsequent grace periods > + * (both expedited and normal) will wait on it. Note that this means that > + * incoming CPUs are not allowed to use RCU read-side critical sections > + * until this function is called. Failing to observe this restriction > + * will result in lockdep splats. > + */ > + void rcu_cpu_starting(unsigned int cpu) > + { > + unsigned long flags; > + unsigned long mask; > + struct rcu_data *rdp; > + struct rcu_node *rnp; > + struct rcu_state *rsp; > + > + for_each_rcu_flavor(rsp) { > + rdp = this_cpu_ptr(rsp->rda); > + rnp = rdp->mynode; > + mask = rdp->grpmask; > + raw_spin_lock_irqsave_rcu_node(rnp, flags); > + rnp->qsmaskinitnext |= mask; > + rnp->expmaskinitnext |= mask; > + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); > + } > + } > + > #ifdef CONFIG_HOTPLUG_CPU > /* > * The CPU is exiting the idle loop into the arch_cpu_idle_dead() > @@@ -4208,9 -4231,12 +4231,11 @@@ void __init rcu_init(void > * this is called early in boot, before either interrupts > * or the scheduler are operational. > */ > - cpu_notifier(rcu_cpu_notify, 0); > pm_notifier(rcu_pm_notify, 0); > - for_each_online_cpu(cpu) > + for_each_online_cpu(cpu) { > - rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu); > + rcutree_prepare_cpu(cpu); > + rcu_cpu_starting(cpu); > + } > } > > #include "tree_exp.h" >