From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754077Ab1EHNeW (ORCPT ); Sun, 8 May 2011 09:34:22 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:58253 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753619Ab1EHNeR (ORCPT ); Sun, 8 May 2011 09:34:17 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org, Gleb Natapov , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 2/3] rcu: provide rcu_virt_note_context_switch() function. Date: Sun, 8 May 2011 06:34:09 -0700 Message-Id: <1304861650-18475-2-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.3.2 In-Reply-To: <20110508133343.GA18287@linux.vnet.ibm.com> References: <20110508133343.GA18287@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Gleb Natapov Provide rcu_virt_note_context_switch() for vitalization use to note quiescent state during guest entry. Signed-off-by: Gleb Natapov Signed-off-by: Paul E. McKenney --- include/linux/rcutiny.h | 8 ++++++++ include/linux/rcutree.h | 10 ++++++++++ kernel/rcutree.c | 1 + 3 files changed, 19 insertions(+), 0 deletions(-) diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 30ebd7c..52b3e02 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -100,6 +100,14 @@ static inline void rcu_note_context_switch(int cpu) } /* + * Take advantage of the fact that there is only one CPU, which + * allows us to ignore virtualization-based context switches. + */ +static inline void rcu_virt_note_context_switch(int cpu) +{ +} + +/* * Return the number of grace periods. */ static inline long rcu_batches_completed(void) diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 284dad1..e65d066 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -35,6 +35,16 @@ extern void rcu_note_context_switch(int cpu); extern int rcu_needs_cpu(int cpu); extern void rcu_cpu_stall_reset(void); +/* + * Note a virtualization-based context switch. This is simply a + * wrapper around rcu_note_context_switch(), which allows TINY_RCU + * to save a few bytes. + */ +static inline void rcu_virt_note_context_switch(int cpu) +{ + rcu_note_context_switch(cpu); +} + #ifdef CONFIG_TREE_PREEMPT_RCU extern void exit_rcu(void); diff --git a/kernel/rcutree.c b/kernel/rcutree.c index b2fe2a2..54ff7eb 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -157,6 +157,7 @@ void rcu_note_context_switch(int cpu) rcu_sched_qs(cpu); rcu_preempt_note_context_switch(cpu); } +EXPORT_SYMBOL_GPL(rcu_note_context_switch); #ifdef CONFIG_NO_HZ DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = { -- 1.7.3.2