Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751884AbaK1JkH (ORCPT ); Fri, 28 Nov 2014 04:40:07 -0500 Received: from cn.fujitsu.com ([59.151.112.132]:39998 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751463AbaK1JkB (ORCPT ); Fri, 28 Nov 2014 04:40:01 -0500 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="44143281" From: Lai Jiangshan To: , "Paul E. McKenney" CC: Lai Jiangshan , Josh Triplett , Steven Rostedt , Mathieu Desnoyers Subject: [RFC PATCH 0/2] tiny_rcu: simplify tiny_rcu Date: Fri, 28 Nov 2014 17:43:31 +0800 Message-ID: <1417167813-11963-1-git-send-email-laijs@cn.fujitsu.com> X-Mailer: git-send-email 1.7.4.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.167.226.103] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Paul These two patches use the special feture of the UP system: In UP, quiescent state == grace period. For rcu_bh, rcu_process_callbacks() == a bh == QS == GP so we can pass rcu_bh-QS and advance GP(and callbacks) in rcu_process_callbacks(). After doing so, rcu_bh_qs() is useless since its work is handled by rcu_process_callbacks(). For rcu_sched, context-switch = QS = GP, thus we can force a context-switch when call_rcu_sched() is happened on idle_task. After doing so, rcu_idle/irq_enter/exit() are useless. These patches remove the useless code to simplify the tiny_rcu. We can change rcu_bh_qs() rcu_idle/irq_enter/exit() to static-inline-functions to reduce the binary size after these two patches accepted. Thanks, Lai Cc: Josh Triplett Cc: Steven Rostedt Cc: Mathieu Desnoyers Lai Jiangshan (2): record rcu_bh quiescent state in RCU_SOFTIRQ tiny_rcu: resched when call_rcu() on idle_task kernel/rcu/rcu.h | 6 ++ kernel/rcu/tiny.c | 134 ++++++++-------------------------------------- kernel/rcu/tiny_plugin.h | 2 +- kernel/rcu/tree.c | 6 -- 4 files changed, 29 insertions(+), 119 deletions(-) -- 1.7.4.4 -- 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/