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authorFrederic Weisbecker <fweisbec@gmail.com>2012-12-16 23:00:34 +0400
committerFrederic Weisbecker <fweisbec@gmail.com>2013-01-27 23:35:47 +0400
commit6a61671bb2f3a1bd12cd17b8fca811a624782632 (patch)
tree0afc2915fb7e517472710a49a524510322dd5baa /include/linux/kvm_host.h
parentc11f11fcbdb5be790c565aed46411486a7586afc (diff)
downloadlinux-6a61671bb2f3a1bd12cd17b8fca811a624782632.tar.xz
cputime: Safely read cputime of full dynticks CPUs
While remotely reading the cputime of a task running in a full dynticks CPU, the values stored in utime/stime fields of struct task_struct may be stale. Its values may be those of the last kernel <-> user transition time snapshot and we need to add the tickless time spent since this snapshot. To fix this, flush the cputime of the dynticks CPUs on kernel <-> user transition and record the time / context where we did this. Then on top of this snapshot and the current time, perform the fixup on the reader side from task_times() accessors. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> [fixed kvm module related build errors] Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
Diffstat (limited to 'include/linux/kvm_host.h')
-rw-r--r--include/linux/kvm_host.h20
1 files changed, 18 insertions, 2 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4fe2396401da..b7996a768eb2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -741,7 +741,7 @@ static inline int kvm_deassign_device(struct kvm *kvm,
}
#endif /* CONFIG_IOMMU_API */
-static inline void guest_enter(void)
+static inline void __guest_enter(void)
{
/*
* This is running in ioctl context so we can avoid
@@ -751,7 +751,7 @@ static inline void guest_enter(void)
current->flags |= PF_VCPU;
}
-static inline void guest_exit(void)
+static inline void __guest_exit(void)
{
/*
* This is running in ioctl context so we can avoid
@@ -761,6 +761,22 @@ static inline void guest_exit(void)
current->flags &= ~PF_VCPU;
}
+#ifdef CONFIG_CONTEXT_TRACKING
+extern void guest_enter(void);
+extern void guest_exit(void);
+
+#else /* !CONFIG_CONTEXT_TRACKING */
+static inline void guest_enter(void)
+{
+ __guest_enter();
+}
+
+static inline void guest_exit(void)
+{
+ __guest_exit();
+}
+#endif /* !CONFIG_CONTEXT_TRACKING */
+
static inline void kvm_guest_enter(void)
{
unsigned long flags;