Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753414Ab1CIWQW (ORCPT ); Wed, 9 Mar 2011 17:16:22 -0500 Received: from flusers.ccur.com ([173.221.59.2]:54203 "EHLO gamx.iccur.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751405Ab1CIWQV (ORCPT ); Wed, 9 Mar 2011 17:16:21 -0500 Date: Wed, 9 Mar 2011 17:15:17 -0500 From: Joe Korty To: Frederic Weisbecker Cc: "Paul E. McKenney" , Peter Zijlstra , Lai Jiangshan , "mathieu.desnoyers@efficios.com" , "dhowells@redhat.com" , "loic.minier@linaro.org" , "dhaval.giani@gmail.com" , "tglx@linutronix.de" , "linux-kernel@vger.kernel.org" , "josh@joshtriplett.org" , "houston.jim@comcast.net" Subject: [PATCH 2/4] jrcu: tap rcu_read_unlock Message-ID: <20110309221517.GB24670@tsunami.ccur.com> Reply-To: Joe Korty References: <4CD912E9.1080907@cn.fujitsu.com> <20101110155419.GC5750@nowhere> <1289410271.2084.25.camel@laptop> <20101111041920.GD3134@linux.vnet.ibm.com> <20101113223046.GB5445@nowhere> <20101116012846.GV2555@linux.vnet.ibm.com> <20101116135230.GA5362@nowhere> <20101116155104.GB2497@linux.vnet.ibm.com> <20101117005229.GC26243@nowhere> <20110307203106.GA23002@tsunami.ccur.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110307203106.GA23002@tsunami.ccur.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1539 Lines: 51 jrcu: tap into rcu_read_unlock(). All places where rcu_read_unlock() is the final lock in a set of nested rcu locks are known rcu quiescent points. This patch recognizes that subset of those which also make the task preemptable. The others are left unrecognized. Not fundamentally needed, accelerates rcu batching. Signed-off-by: Joe Korty Index: b/include/linux/jrcu.h =================================================================== --- a/include/linux/jrcu.h +++ b/include/linux/jrcu.h @@ -21,8 +21,10 @@ #ifndef __LINUX_JRCU_H #define __LINUX_JRCU_H +extern void rcu_read_unlock_jrcu(void); + #define __rcu_read_lock() preempt_disable() -#define __rcu_read_unlock() preempt_enable() +#define __rcu_read_unlock() rcu_read_unlock_jrcu() #define __rcu_read_lock_bh() __rcu_read_lock() #define __rcu_read_unlock_bh() __rcu_read_unlock() Index: b/kernel/jrcu.c =================================================================== --- a/kernel/jrcu.c +++ b/kernel/jrcu.c @@ -153,6 +153,14 @@ static inline void rcu_eob(int cpu) } } +void rcu_read_unlock_jrcu(void) +{ + if (preempt_count() == 1) + rcu_eob(rcu_cpu()); + preempt_enable(); +} +EXPORT_SYMBOL_GPL(rcu_read_unlock_jrcu); + void rcu_note_context_switch(int cpu) { rcu_eob(cpu); -- 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/