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From: riel@redhat.com
To: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, mtosatti@redhat.com,
	mingo@kernel.org, ak@linux.intel.com, oleg@redhat.com,
	masami.hiramatsu.pt@hitachi.com, fweisbec@gmail.com,
	paulmck@linux.vnet.ibm.com, lcapitulino@redhat.com,
	pbonzini@redhat.com
Subject: [PATCH 1/4] rcu,nohz: add state parameter to context_tracking_user_enter/exit
Date: Thu,  5 Feb 2015 11:35:31 -0500	[thread overview]
Message-ID: <1423154134-17391-2-git-send-email-riel@redhat.com> (raw)
In-Reply-To: <1423154134-17391-1-git-send-email-riel@redhat.com>

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>
---
 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 16:35 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-05 16:35 [PATCH 0/4] rcu,nohz,kvm: use RCU extended quiescent state when running KVM guest riel
2015-02-05 16:35 ` riel [this message]
2015-02-05 16:35 ` [PATCH 2/4] rcu,nohz: run vtime_user_enter/exit only when state == IN_USER riel
2015-02-05 16:35 ` [PATCH 3/4] nohz,kvm: export context_tracking_user_enter/exit riel
2015-02-05 16:35 ` [PATCH 4/4] kvm,rcu: use RCU extended quiescent state when running KVM guest riel
2015-02-05 16:44   ` Christian Borntraeger
2015-02-05 16:52     ` Rik van Riel
2015-02-05 17:50       ` Paul E. McKenney
2015-02-05 18:09         ` Rik van Riel
2015-02-05 18:56           ` Paul E. McKenney
2015-02-05 18:59             ` Rik van Riel
2015-02-05 19:02             ` Rik van Riel
2015-02-05 19:27               ` Paul E. McKenney
2015-02-05 20:19                 ` Rik van Riel

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