Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751162AbWH1QLH (ORCPT ); Mon, 28 Aug 2006 12:11:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751166AbWH1QLH (ORCPT ); Mon, 28 Aug 2006 12:11:07 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:62156 "EHLO e32.co.us.ibm.com") by vger.kernel.org with ESMTP id S1751161AbWH1QLE (ORCPT ); Mon, 28 Aug 2006 12:11:04 -0400 Date: Mon, 28 Aug 2006 21:41:12 +0530 From: Dipankar Sarma To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Ingo Molnar , Paul E McKenney Subject: Re: [PATCH 2/4] RCU: use a separate softirq Message-ID: <20060828161112.GD3325@in.ibm.com> Reply-To: dipankar@in.ibm.com References: <20060828160845.GB3325@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060828160845.GB3325@in.ibm.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3428 Lines: 97 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. 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/