Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751489AbWHaBNH (ORCPT ); Wed, 30 Aug 2006 21:13:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751574AbWHaBNH (ORCPT ); Wed, 30 Aug 2006 21:13:07 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.146]:4004 "EHLO e6.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1751489AbWHaBNE (ORCPT ); Wed, 30 Aug 2006 21:13:04 -0400 Date: Wed, 30 Aug 2006 18:13:48 -0700 From: "Paul E. McKenney" To: Dipankar Sarma Cc: linux-kernel@vger.kernel.org, Andrew Morton , Ingo Molnar Subject: Re: [PATCH 2/4] RCU: use a separate softirq Message-ID: <20060831011348.GB2961@us.ibm.com> Reply-To: paulmck@us.ibm.com References: <20060828160845.GB3325@in.ibm.com> <20060828161112.GD3325@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060828161112.GD3325@in.ibm.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3723 Lines: 100 On Mon, Aug 28, 2006 at 09:41:12PM +0530, Dipankar Sarma wrote: > > Finally, RCU gets its own softirq. With it being used extensively, > the per-cpu tasklet used earlier was just a softirq with overheads. > This makes things more efficient. Acked-by: Paul E. McKenney > Signed-off-by: Dipankar Sarma > --- > > > include/linux/interrupt.h | 3 ++- > kernel/rcuclassic.c | 12 +++++------- > 2 files changed, 7 insertions(+), 8 deletions(-) > > diff -puN kernel/rcuclassic.c~rcu-softirq kernel/rcuclassic.c > --- linux-2.6.18-rc3-rcu/kernel/rcuclassic.c~rcu-softirq 2006-08-27 01:01:15.000000000 +0530 > +++ linux-2.6.18-rc3-rcu-dipankar/kernel/rcuclassic.c 2006-08-27 01:01:15.000000000 +0530 > @@ -69,7 +69,6 @@ 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; > @@ -212,7 +211,7 @@ 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); > } > > /* > @@ -363,7 +362,6 @@ 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 > @@ -375,7 +373,7 @@ 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) > @@ -420,7 +418,7 @@ 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)); > @@ -484,7 +482,7 @@ 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, > @@ -507,7 +505,7 @@ 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 __devinit rcu_cpu_notify(struct notifier_block *self, > diff -puN include/linux/interrupt.h~rcu-softirq include/linux/interrupt.h > --- linux-2.6.18-rc3-rcu/include/linux/interrupt.h~rcu-softirq 2006-08-27 01:01:15.000000000 +0530 > +++ linux-2.6.18-rc3-rcu-dipankar/include/linux/interrupt.h 2006-08-27 01:01:15.000000000 +0530 > @@ -219,7 +219,8 @@ enum > NET_TX_SOFTIRQ, > NET_RX_SOFTIRQ, > BLOCK_SOFTIRQ, > - TASKLET_SOFTIRQ > + TASKLET_SOFTIRQ, > + RCU_SOFTIRQ /* Preferable RCU should always be the last softirq */ > }; > > /* softirq mask and active fields moved to irq_cpustat_t in > > _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/