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authorFrederic Weisbecker <fweisbec@gmail.com>2013-07-11 21:42:13 +0400
committerFrederic Weisbecker <fweisbec@gmail.com>2013-08-14 19:14:47 +0400
commit73d424f9af7b571276e6284617cb59726d47bf12 (patch)
tree6ee47dd0327e67c8514ebfefc12728b030e79ae5 /include/linux/context_tracking.h
parent48d6a816a8bf36e2a197c322697323003bdc1cfe (diff)
downloadlinux-73d424f9af7b571276e6284617cb59726d47bf12.tar.xz
context_tracking: Optimize context switch off case with static keys
No need for syscall slowpath if no CPU is full dynticks, rather nop this in this case. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
Diffstat (limited to 'include/linux/context_tracking.h')
-rw-r--r--include/linux/context_tracking.h11
1 files changed, 9 insertions, 2 deletions
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index 8854eadb2142..e070ea5dadac 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -40,6 +40,8 @@ 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_task_switch(struct task_struct *prev,
+ struct task_struct *next);
static inline void user_enter(void)
{
@@ -74,8 +76,12 @@ static inline void exception_exit(enum ctx_state prev_ctx)
}
}
-extern void context_tracking_task_switch(struct task_struct *prev,
- struct task_struct *next);
+static inline void context_tracking_task_switch(struct task_struct *prev,
+ struct task_struct *next)
+{
+ if (static_key_false(&context_tracking_enabled))
+ __context_tracking_task_switch(prev, next);
+}
#else
static inline bool context_tracking_in_user(void) { return false; }
static inline void user_enter(void) { }
@@ -112,6 +118,7 @@ static inline void guest_exit(void)
else
current->flags &= ~PF_VCPU;
}
+
#else
static inline void guest_enter(void)
{