Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754635Ab1EDQfx (ORCPT ); Wed, 4 May 2011 12:35:53 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:36234 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754532Ab1EDQfv (ORCPT ); Wed, 4 May 2011 12:35:51 -0400 Date: Wed, 4 May 2011 09:35:42 -0700 From: "Paul E. McKenney" To: Gleb Natapov Cc: linux-kernel@vger.kernel.org, avi@redhat.com, mtosatti@redhat.com, kvm@vger.kernel.org Subject: Re: [PATCH 1/2] rcu: provide rcu_virt_note_context_switch() function. Message-ID: <20110504163542.GA2641@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1304515864-17105-1-git-send-email-gleb@redhat.com> <1304515864-17105-2-git-send-email-gleb@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1304515864-17105-2-git-send-email-gleb@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2448 Lines: 78 On Wed, May 04, 2011 at 04:31:03PM +0300, Gleb Natapov wrote: > Provide rcu_virt_note_context_switch() for vitalization use to note > quiescent state during guest entry. Very good, queued on -rcu. Unless you tell me otherwise, I will assume that you want to carry the patch modifying KVM to use this. Thanx, Paul > Signed-off-by: Gleb Natapov > --- > 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 3a93348..b2a906e 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 dd4aea8..0837d63 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -124,6 +124,7 @@ 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) = { > -- > 1.7.4.4 > -- 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/