cpuacct: Introduce cgroup_account_cputime[_field]()

Introduce cgroup_account_cputime[_field]() which wrap cpuacct_charge()
and cgroup_account_field().  This doesn't introduce any functional
changes and will be used to add cgroup basic resource accounting.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index d023ac5..6cd5793 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -22,6 +22,7 @@
 #include <linux/nsproxy.h>
 #include <linux/user_namespace.h>
 #include <linux/refcount.h>
+#include <linux/kernel_stat.h>
 
 #include <linux/cgroup-defs.h>
 
@@ -689,6 +690,43 @@
 #endif /* !CONFIG_CGROUPS */
 
 /*
+ * Basic resource stats.
+ */
+#ifdef CONFIG_CGROUPS
+
+#ifdef CONFIG_CGROUP_CPUACCT
+void cpuacct_charge(struct task_struct *tsk, u64 cputime);
+void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
+#else
+static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
+static inline void cpuacct_account_field(struct task_struct *tsk, int index,
+					 u64 val) {}
+#endif
+
+static inline void cgroup_account_cputime(struct task_struct *task,
+					  u64 delta_exec)
+{
+	cpuacct_charge(task, delta_exec);
+}
+
+static inline void cgroup_account_cputime_field(struct task_struct *task,
+						enum cpu_usage_stat index,
+						u64 delta_exec)
+{
+	cpuacct_account_field(task, index, delta_exec);
+}
+
+#else	/* CONFIG_CGROUPS */
+
+static inline void cgroup_account_cputime(struct task_struct *task,
+					  u64 delta_exec) {}
+static inline void cgroup_account_cputime_field(struct task_struct *task,
+						enum cpu_usage_stat index,
+						u64 delta_exec) {}
+
+#endif	/* CONFIG_CGROUPS */
+
+/*
  * sock->sk_cgrp_data handling.  For more info, see sock_cgroup_data
  * definition in cgroup-defs.h.
  */