From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760934AbXGPUNJ (ORCPT ); Mon, 16 Jul 2007 16:13:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754877AbXGPUM5 (ORCPT ); Mon, 16 Jul 2007 16:12:57 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:55957 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752820AbXGPUM4 (ORCPT ); Mon, 16 Jul 2007 16:12:56 -0400 Date: Mon, 16 Jul 2007 13:12:51 -0700 From: "Paul E. McKenney" To: Steven Rostedt Cc: LKML , Linus Torvalds , Ingo Molnar , Andrew Morton , Thomas Gleixner , Christoph Hellwig , john stultz , Oleg Nesterov , Dipankar Sarma , "David S. Miller" , kuznet@ms2.inr.ac.ru, Jonathan Corbet , Arjan van de Ven , Arnd Bergmann Subject: Re: [RFC PATCH 1/8] Convert the RCU tasklet into a softirq Message-ID: <20070716201251.GB12458@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20070627193633.025544061@goodmis.org> <20070627194327.241131609@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070627194327.241131609@goodmis.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 27, 2007 at 03:36:34PM -0400, Steven Rostedt wrote: > I believe this was originally done by Dipankar Sarma. I pulled these > changes from the -rt kernel. > > For better preformance, RCU should use a softirq instead of a > tasklet. Acked-by: Paul E. McKenney Tested-by: Paul E. McKenney Tested with both kernbench and rcutorture on i386, x86_64, and ppc64. Thanx, Paul > From: Dipankar Sarma > Signed-off-by: Steven Rostedt > > Index: linux-2.6-test/include/linux/interrupt.h > =================================================================== > --- linux-2.6-test.orig/include/linux/interrupt.h > +++ linux-2.6-test/include/linux/interrupt.h > @@ -245,6 +245,9 @@ enum > #ifdef CONFIG_HIGH_RES_TIMERS > HRTIMER_SOFTIRQ, > #endif > + RCU_SOFTIRQ, /* Preferable RCU should always be the last softirq */ > + /* Entries after this are ignored in split softirq mode */ > + MAX_SOFTIRQ, > }; > > /* softirq mask and active fields moved to irq_cpustat_t in > Index: linux-2.6-test/kernel/rcupdate.c > =================================================================== > --- linux-2.6-test.orig/kernel/rcupdate.c > +++ linux-2.6-test/kernel/rcupdate.c > @@ -67,7 +67,6 @@ DEFINE_PER_CPU(struct rcu_data, rcu_data > DEFINE_PER_CPU(struct rcu_data, rcu_bh_data) = { 0L }; > > /* Fake initialization required by compiler */ > -static DEFINE_PER_CPU(struct tasklet_struct, rcu_tasklet) = {NULL}; > static int blimit = 10; > static int qhimark = 10000; > static int qlowmark = 100; > @@ -253,7 +252,7 @@ static void rcu_do_batch(struct rcu_data > if (!rdp->donelist) > rdp->donetail = &rdp->donelist; > else > - tasklet_schedule(&per_cpu(rcu_tasklet, rdp->cpu)); > + raise_softirq(RCU_SOFTIRQ); > } > > /* > @@ -405,7 +404,6 @@ static void rcu_offline_cpu(int cpu) > &per_cpu(rcu_bh_data, cpu)); > put_cpu_var(rcu_data); > put_cpu_var(rcu_bh_data); > - tasklet_kill_immediate(&per_cpu(rcu_tasklet, cpu), cpu); > } > > #else > @@ -417,7 +415,7 @@ static void rcu_offline_cpu(int cpu) > #endif > > /* > - * This does the RCU processing work from tasklet context. > + * This does the RCU processing work from softirq context. > */ > static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp, > struct rcu_data *rdp) > @@ -462,7 +460,7 @@ static void __rcu_process_callbacks(stru > rcu_do_batch(rdp); > } > > -static void rcu_process_callbacks(unsigned long unused) > +static void rcu_process_callbacks(struct softirq_action *unused) > { > __rcu_process_callbacks(&rcu_ctrlblk, &__get_cpu_var(rcu_data)); > __rcu_process_callbacks(&rcu_bh_ctrlblk, &__get_cpu_var(rcu_bh_data)); > @@ -526,7 +524,7 @@ void rcu_check_callbacks(int cpu, int us > rcu_bh_qsctr_inc(cpu); > } else if (!in_softirq()) > rcu_bh_qsctr_inc(cpu); > - tasklet_schedule(&per_cpu(rcu_tasklet, cpu)); > + raise_softirq(RCU_SOFTIRQ); > } > > static void rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp, > @@ -549,7 +547,7 @@ static void __devinit rcu_online_cpu(int > > rcu_init_percpu_data(cpu, &rcu_ctrlblk, rdp); > rcu_init_percpu_data(cpu, &rcu_bh_ctrlblk, bh_rdp); > - tasklet_init(&per_cpu(rcu_tasklet, cpu), rcu_process_callbacks, 0UL); > + open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL); > } > > static int __cpuinit rcu_cpu_notify(struct notifier_block *self, > > --