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authorFrederic Weisbecker <fweisbec@gmail.com>2013-07-12 19:02:30 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2013-08-13 00:40:44 +0200
commit2d854e5738cded368a0759f85b1197f5c044513d (patch)
tree14d2353e1dd594e9b695c250e3955c1da1eaf102
parentfbb00b568bc93073452d2a0f9f06e7c33d16eece (diff)
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context_tracing: Fix guest accounting with native vtime
1) If context tracking is enabled with native vtime accounting (which combo is useless except for dev testing), we call vtime_guest_enter() and vtime_guest_exit() on host <-> guest switches. But those are stubs in this configurations. As a result, cputime is not correctly flushed on kvm context switches. 2) If context tracking runs but is disabled on some CPUs, those CPUs end up calling __guest_enter/__guest_exit which in turn call vtime_account_system(). We don't want to call this because we run in tick based accounting for these CPUs. Refactor the guest_enter/guest_exit code such that all combinations finally work. 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>
-rw-r--r--include/linux/context_tracking.h52
-rw-r--r--kernel/context_tracking.c6
2 files changed, 26 insertions, 32 deletions
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index fc09d7b0dacf..5984f2556d13 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -20,25 +20,6 @@ struct context_tracking {
} state;
};
-static inline void __guest_enter(void)
-{
- /*
- * This is running in ioctl context so we can avoid
- * the call to vtime_account() with its unnecessary idle check.
- */
- vtime_account_system(current);
- current->flags |= PF_VCPU;
-}
-
-static inline void __guest_exit(void)
-{
- /*
- * This is running in ioctl context so we can avoid
- * the call to vtime_account() with its unnecessary idle check.
- */
- vtime_account_system(current);
- current->flags &= ~PF_VCPU;
-}
#ifdef CONFIG_CONTEXT_TRACKING
DECLARE_PER_CPU(struct context_tracking, context_tracking);
@@ -56,9 +37,6 @@ static inline bool context_tracking_active(void)
extern void user_enter(void);
extern void user_exit(void);
-extern void guest_enter(void);
-extern void guest_exit(void);
-
static inline enum ctx_state exception_enter(void)
{
enum ctx_state prev_ctx;
@@ -81,21 +59,35 @@ extern void context_tracking_task_switch(struct task_struct *prev,
static inline bool context_tracking_in_user(void) { return false; }
static inline void user_enter(void) { }
static inline void user_exit(void) { }
+static inline enum ctx_state exception_enter(void) { return 0; }
+static inline void exception_exit(enum ctx_state prev_ctx) { }
+static inline void context_tracking_task_switch(struct task_struct *prev,
+ struct task_struct *next) { }
+#endif /* !CONFIG_CONTEXT_TRACKING */
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+extern void guest_enter(void);
+extern void guest_exit(void);
+#else
static inline void guest_enter(void)
{
- __guest_enter();
+ /*
+ * This is running in ioctl context so we can avoid
+ * the call to vtime_account() with its unnecessary idle check.
+ */
+ vtime_account_system(current);
+ current->flags |= PF_VCPU;
}
static inline void guest_exit(void)
{
- __guest_exit();
+ /*
+ * This is running in ioctl context so we can avoid
+ * the call to vtime_account() with its unnecessary idle check.
+ */
+ vtime_account_system(current);
+ current->flags &= ~PF_VCPU;
}
-
-static inline enum ctx_state exception_enter(void) { return 0; }
-static inline void exception_exit(enum ctx_state prev_ctx) { }
-static inline void context_tracking_task_switch(struct task_struct *prev,
- struct task_struct *next) { }
-#endif /* !CONFIG_CONTEXT_TRACKING */
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
#endif
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 942835c12ae5..1f47119c5b09 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -141,12 +141,13 @@ void user_exit(void)
local_irq_restore(flags);
}
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
void guest_enter(void)
{
if (vtime_accounting_enabled())
vtime_guest_enter(current);
else
- __guest_enter();
+ current->flags |= PF_VCPU;
}
EXPORT_SYMBOL_GPL(guest_enter);
@@ -155,9 +156,10 @@ void guest_exit(void)
if (vtime_accounting_enabled())
vtime_guest_exit(current);
else
- __guest_exit();
+ current->flags &= ~PF_VCPU;
}
EXPORT_SYMBOL_GPL(guest_exit);
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
/**