sched/headers: Move cputime functionality from <linux/sched.h> and <linux/cputime.h> into <linux/sched/cputime.h>

Move cputime related functionality out of <linux/sched.h>, as most code
that includes <linux/sched.h> does not use that functionality.

Move data types that are not included in task_struct directly to
the signal definitions, into <linux/sched/signal.h>.

Also merge the (small) existing <linux/cputime.h> header into <linux/sched/cputime.h>.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 214 insertions, 1 deletions

diff --git a/include/linux/sched/cputime.h b/include/linux/sched/cputime.h
index 6ed4fe43de28..4c5b9735c1ae 100644
--- a/include/linux/sched/cputime.h
+++ b/include/linux/sched/cputime.h
@@ -2,6 +2,186 @@
 #define _LINUX_SCHED_CPUTIME_H
 
 #include <linux/sched/signal.h>
-#include <linux/cputime.h>
+
+/*
+ * cputime accounting APIs:
+ */
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+#include <asm/cputime.h>
+
+#ifndef cputime_to_nsecs
+# define cputime_to_nsecs(__ct)	\
+	(cputime_to_usecs(__ct) * NSEC_PER_USEC)
+#endif
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+extern void task_cputime(struct task_struct *t,
+			 u64 *utime, u64 *stime);
+extern u64 task_gtime(struct task_struct *t);
+#else
+static inline void task_cputime(struct task_struct *t,
+				u64 *utime, u64 *stime)
+{
+	*utime = t->utime;
+	*stime = t->stime;
+}
+
+static inline u64 task_gtime(struct task_struct *t)
+{
+	return t->gtime;
+}
+#endif
+
+#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
+static inline void task_cputime_scaled(struct task_struct *t,
+				       u64 *utimescaled,
+				       u64 *stimescaled)
+{
+	*utimescaled = t->utimescaled;
+	*stimescaled = t->stimescaled;
+}
+#else
+static inline void task_cputime_scaled(struct task_struct *t,
+				       u64 *utimescaled,
+				       u64 *stimescaled)
+{
+	task_cputime(t, utimescaled, stimescaled);
+}
+#endif
+
+extern void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st);
+extern void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st);
+
+
+/*
+ * Thread group CPU time accounting.
+ */
+void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times);
+void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times);
+
+
+/*
+ * The following are functions that support scheduler-internal time accounting.
+ * These functions are generally called at the timer tick.  None of this depends
+ * on CONFIG_SCHEDSTATS.
+ */
+
+/**
+ * get_running_cputimer - return &tsk->signal->cputimer if cputimer is running
+ *
+ * @tsk:	Pointer to target task.
+ */
+#ifdef CONFIG_POSIX_TIMERS
+static inline
+struct thread_group_cputimer *get_running_cputimer(struct task_struct *tsk)
+{
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+
+	/* Check if cputimer isn't running. This is accessed without locking. */
+	if (!READ_ONCE(cputimer->running))
+		return NULL;
+
+	/*
+	 * After we flush the task's sum_exec_runtime to sig->sum_sched_runtime
+	 * in __exit_signal(), we won't account to the signal struct further
+	 * cputime consumed by that task, even though the task can still be
+	 * ticking after __exit_signal().
+	 *
+	 * In order to keep a consistent behaviour between thread group cputime
+	 * and thread group cputimer accounting, lets also ignore the cputime
+	 * elapsing after __exit_signal() in any thread group timer running.
+	 *
+	 * This makes sure that POSIX CPU clocks and timers are synchronized, so
+	 * that a POSIX CPU timer won't expire while the corresponding POSIX CPU
+	 * clock delta is behind the expiring timer value.
+	 */
+	if (unlikely(!tsk->sighand))
+		return NULL;
+
+	return cputimer;
+}
+#else
+static inline
+struct thread_group_cputimer *get_running_cputimer(struct task_struct *tsk)
+{
+	return NULL;
+}
+#endif
+
+/**
+ * account_group_user_time - Maintain utime for a thread group.
+ *
+ * @tsk:	Pointer to task structure.
+ * @cputime:	Time value by which to increment the utime field of the
+ *		thread_group_cputime structure.
+ *
+ * If thread group time is being maintained, get the structure for the
+ * running CPU and update the utime field there.
+ */
+static inline void account_group_user_time(struct task_struct *tsk,
+					   u64 cputime)
+{
+	struct thread_group_cputimer *cputimer = get_running_cputimer(tsk);
+
+	if (!cputimer)
+		return;
+
+	atomic64_add(cputime, &cputimer->cputime_atomic.utime);
+}
+
+/**
+ * account_group_system_time - Maintain stime for a thread group.
+ *
+ * @tsk:	Pointer to task structure.
+ * @cputime:	Time value by which to increment the stime field of the
+ *		thread_group_cputime structure.
+ *
+ * If thread group time is being maintained, get the structure for the
+ * running CPU and update the stime field there.
+ */
+static inline void account_group_system_time(struct task_struct *tsk,
+					     u64 cputime)
+{
+	struct thread_group_cputimer *cputimer = get_running_cputimer(tsk);
+
+	if (!cputimer)
+		return;
+
+	atomic64_add(cputime, &cputimer->cputime_atomic.stime);
+}
+
+/**
+ * account_group_exec_runtime - Maintain exec runtime for a thread group.
+ *
+ * @tsk:	Pointer to task structure.
+ * @ns:		Time value by which to increment the sum_exec_runtime field
+ *		of the thread_group_cputime structure.
+ *
+ * If thread group time is being maintained, get the structure for the
+ * running CPU and update the sum_exec_runtime field there.
+ */
+static inline void account_group_exec_runtime(struct task_struct *tsk,
+					      unsigned long long ns)
+{
+	struct thread_group_cputimer *cputimer = get_running_cputimer(tsk);
+
+	if (!cputimer)
+		return;
+
+	atomic64_add(ns, &cputimer->cputime_atomic.sum_exec_runtime);
+}
+
+static inline void prev_cputime_init(struct prev_cputime *prev)
+{
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+	prev->utime = prev->stime = 0;
+	raw_spin_lock_init(&prev->lock);
+#endif
+}
+
+extern unsigned long long
+task_sched_runtime(struct task_struct *task);
 
 #endif /* _LINUX_SCHED_CPUTIME_H */
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index b3545fb4333a..2cf446704cd4 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -36,6 +36,39 @@ struct cpu_itimer {
 };
 
 /*
+ * This is the atomic variant of task_cputime, which can be used for
+ * storing and updating task_cputime statistics without locking.
+ */
+struct task_cputime_atomic {
+	atomic64_t utime;
+	atomic64_t stime;
+	atomic64_t sum_exec_runtime;
+};
+
+#define INIT_CPUTIME_ATOMIC \
+	(struct task_cputime_atomic) {				\
+		.utime = ATOMIC64_INIT(0),			\
+		.stime = ATOMIC64_INIT(0),			\
+		.sum_exec_runtime = ATOMIC64_INIT(0),		\
+	}
+/**
+ * struct thread_group_cputimer - thread group interval timer counts
+ * @cputime_atomic:	atomic thread group interval timers.
+ * @running:		true when there are timers running and
+ *			@cputime_atomic receives updates.
+ * @checking_timer:	true when a thread in the group is in the
+ *			process of checking for thread group timers.
+ *
+ * This structure contains the version of task_cputime, above, that is
+ * used for thread group CPU timer calculations.
+ */
+struct thread_group_cputimer {
+	struct task_cputime_atomic cputime_atomic;
+	bool running;
+	bool checking_timer;
+};
+
+/*
  * NOTE! "signal_struct" does not have its own
  * locking, because a shared signal_struct always
  * implies a shared sighand_struct, so locking