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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: riel@redhat.com
Cc: kvm@vger.kernel.org, borntraeger@de.ibm.com,
	linux-kernel@vger.kernel.org, mtosatti@redhat.com,
	mingo@kernel.orgm, ak@linux.intel.com, oleg@redhat.com,
	masami.hiramatsu.pt@hitachi.com, fweisbec@gmail.com,
	lcapitulino@redhat.com, pbonzini@redhat.com
Subject: Re: [PATCH 1/5] rcu,nohz: add state parameter to context_tracking_user_enter/exit
Date: Thu, 5 Feb 2015 15:55:26 -0800	[thread overview]
Message-ID: <20150205235526.GQ5370@linux.vnet.ibm.com> (raw)
In-Reply-To: <1423167832-17609-2-git-send-email-riel@redhat.com>

On Thu, Feb 05, 2015 at 03:23:48PM -0500, riel@redhat.com wrote:
> From: Rik van Riel <riel@redhat.com>
> 
> Add the expected ctx_state as a parameter to context_tracking_user_enter
> and context_tracking_user_exit, allowing the same functions to not just
> track kernel <> user space switching, but also kernel <> guest transitions.
> 
> Signed-off-by: Rik van Riel <riel@redhat.com>

Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

> ---
>  include/linux/context_tracking.h | 12 ++++++------
>  kernel/context_tracking.c        | 10 +++++-----
>  2 files changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
> index 37b81bd51ec0..bd9f000fc98d 100644
> --- a/include/linux/context_tracking.h
> +++ b/include/linux/context_tracking.h
> @@ -10,21 +10,21 @@
>  #ifdef CONFIG_CONTEXT_TRACKING
>  extern void context_tracking_cpu_set(int cpu);
> 
> -extern void context_tracking_user_enter(void);
> -extern void context_tracking_user_exit(void);
> +extern void context_tracking_user_enter(enum ctx_state state);
> +extern void context_tracking_user_exit(enum ctx_state state);
>  extern void __context_tracking_task_switch(struct task_struct *prev,
>  					   struct task_struct *next);
> 
>  static inline void user_enter(void)
>  {
>  	if (context_tracking_is_enabled())
> -		context_tracking_user_enter();
> +		context_tracking_user_enter(IN_USER);
> 
>  }
>  static inline void user_exit(void)
>  {
>  	if (context_tracking_is_enabled())
> -		context_tracking_user_exit();
> +		context_tracking_user_exit(IN_USER);
>  }
> 
>  static inline enum ctx_state exception_enter(void)
> @@ -35,7 +35,7 @@ static inline enum ctx_state exception_enter(void)
>  		return 0;
> 
>  	prev_ctx = this_cpu_read(context_tracking.state);
> -	context_tracking_user_exit();
> +	context_tracking_user_exit(prev_ctx);
> 
>  	return prev_ctx;
>  }
> @@ -44,7 +44,7 @@ static inline void exception_exit(enum ctx_state prev_ctx)
>  {
>  	if (context_tracking_is_enabled()) {
>  		if (prev_ctx == IN_USER)
> -			context_tracking_user_enter();
> +			context_tracking_user_enter(prev_ctx);
>  	}
>  }
> 
> diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
> index 937ecdfdf258..4c010787c9ec 100644
> --- a/kernel/context_tracking.c
> +++ b/kernel/context_tracking.c
> @@ -47,7 +47,7 @@ void context_tracking_cpu_set(int cpu)
>   * to execute won't use any RCU read side critical section because this
>   * function sets RCU in extended quiescent state.
>   */
> -void context_tracking_user_enter(void)
> +void context_tracking_user_enter(enum ctx_state state)
>  {
>  	unsigned long flags;
> 
> @@ -75,7 +75,7 @@ void context_tracking_user_enter(void)
>  	WARN_ON_ONCE(!current->mm);
> 
>  	local_irq_save(flags);
> -	if ( __this_cpu_read(context_tracking.state) != IN_USER) {
> +	if ( __this_cpu_read(context_tracking.state) != state) {
>  		if (__this_cpu_read(context_tracking.active)) {
>  			trace_user_enter(0);
>  			/*
> @@ -101,7 +101,7 @@ void context_tracking_user_enter(void)
>  		 * OTOH we can spare the calls to vtime and RCU when context_tracking.active
>  		 * is false because we know that CPU is not tickless.
>  		 */
> -		__this_cpu_write(context_tracking.state, IN_USER);
> +		__this_cpu_write(context_tracking.state, state);
>  	}
>  	local_irq_restore(flags);
>  }
> @@ -118,7 +118,7 @@ NOKPROBE_SYMBOL(context_tracking_user_enter);
>   * This call supports re-entrancy. This way it can be called from any exception
>   * handler without needing to know if we came from userspace or not.
>   */
> -void context_tracking_user_exit(void)
> +void context_tracking_user_exit(enum ctx_state state)
>  {
>  	unsigned long flags;
> 
> @@ -129,7 +129,7 @@ void context_tracking_user_exit(void)
>  		return;
> 
>  	local_irq_save(flags);
> -	if (__this_cpu_read(context_tracking.state) == IN_USER) {
> +	if (__this_cpu_read(context_tracking.state) == state) {
>  		if (__this_cpu_read(context_tracking.active)) {
>  			/*
>  			 * We are going to run code that may use RCU. Inform
> -- 
> 1.9.3
> 


  reply	other threads:[~2015-02-05 23:55 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-05 20:23 [PATCH v2 0/5] rcu,nohz,kvm: use RCU extended quiescent state when running KVM guest riel
2015-02-05 20:23 ` [PATCH 1/5] rcu,nohz: add state parameter to context_tracking_user_enter/exit riel
2015-02-05 23:55   ` Paul E. McKenney [this message]
2015-02-06 10:15     ` Paolo Bonzini
2015-02-06 13:41       ` Paul E. McKenney
2015-02-06 17:22   ` Frederic Weisbecker
2015-02-06 18:20     ` Rik van Riel
2015-02-06 18:23       ` Frederic Weisbecker
2015-02-06 18:51         ` Rik van Riel
2015-02-06 23:15           ` Frederic Weisbecker
2015-02-07  3:53             ` Rik van Riel
2015-02-07  6:34               ` Paul E. McKenney
2015-02-07  7:14                 ` Paul E. McKenney
2015-02-07  8:30                   ` Frederic Weisbecker
2015-02-07 11:29                     ` Rik van Riel
2015-02-07 20:06                     ` Paul E. McKenney
2015-02-09 15:42                       ` Rik van Riel
2015-02-05 20:23 ` [PATCH 2/5] rcu,nohz: run vtime_user_enter/exit only when state == IN_USER riel
2015-02-05 20:23 ` [PATCH 3/5] nohz,kvm: export context_tracking_user_enter/exit riel
2015-02-05 23:55   ` Paul E. McKenney
2015-02-05 20:23 ` [PATCH 4/5] kvm,rcu,nohz: use RCU extended quiescent state when running KVM guest riel
2015-02-05 23:56   ` Paul E. McKenney
2015-02-06 18:01   ` Frederic Weisbecker
2015-02-06 23:24   ` Frederic Weisbecker
2015-02-05 20:23 ` [PATCH 5/5] nohz: add stub context_tracking_is_enabled riel
2015-02-05 23:56   ` Paul E. McKenney
2015-02-06 13:46 ` [PATCH v2 0/5] rcu,nohz,kvm: use RCU extended quiescent state when running KVM guest Frederic Weisbecker
2015-02-06 13:50   ` Paolo Bonzini
2015-02-06 16:19     ` Paul E. McKenney
2015-02-06 18:09     ` Frederic Weisbecker
2015-02-06 14:56   ` Rik van Riel
2015-02-06 18:05     ` Frederic Weisbecker
2015-02-06 15:00 ` Christian Borntraeger
2015-02-06 18:20   ` Frederic Weisbecker

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