3 files changed, 101 insertions, 0 deletions

diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h
new file mode 100644
index 000000000000..9572cfa1f129
--- /dev/null
+++ b/include/linux/delayacct.h
@@ -0,0 +1,69 @@
+/* delayacct.h - per-task delay accounting
+ *
+ * Copyright (C) Shailabh Nagar, IBM Corp. 2006
+ *
+ * This program is free software;  you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY;  without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ * the GNU General Public License for more details.
+ *
+ */
+
+#ifndef _LINUX_DELAYACCT_H
+#define _LINUX_DELAYACCT_H
+
+#include <linux/sched.h>
+
+#ifdef CONFIG_TASK_DELAY_ACCT
+
+extern int delayacct_on;        /* Delay accounting turned on/off */
+extern kmem_cache_t *delayacct_cache;
+extern void delayacct_init(void);
+extern void __delayacct_tsk_init(struct task_struct *);
+extern void __delayacct_tsk_exit(struct task_struct *);
+
+static inline void delayacct_set_flag(int flag)
+{
+        if (current->delays)
+                current->delays->flags |= flag;
+}
+
+static inline void delayacct_clear_flag(int flag)
+{
+        if (current->delays)
+                current->delays->flags &= ~flag;
+}
+
+static inline void delayacct_tsk_init(struct task_struct *tsk)
+{
+        /* reinitialize in case parent's non-null pointer was dup'ed*/
+        tsk->delays = NULL;
+        if (unlikely(delayacct_on))
+                __delayacct_tsk_init(tsk);
+}
+
+static inline void delayacct_tsk_exit(struct task_struct *tsk)
+{
+        if (tsk->delays)
+                __delayacct_tsk_exit(tsk);
+}
+
+#else
+static inline void delayacct_set_flag(int flag)
+{}
+static inline void delayacct_clear_flag(int flag)
+{}
+static inline void delayacct_init(void)
+{}
+static inline void delayacct_tsk_init(struct task_struct *tsk)
+{}
+static inline void delayacct_tsk_exit(struct task_struct *tsk)
+{}
+#endif /* CONFIG_TASK_DELAY_ACCT */
+
+#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1c876e27ff93..7a54e62763c5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -552,6 +552,23 @@ struct sched_info {
 extern struct file_operations proc_schedstat_operations;
 #endif
 
+#ifdef CONFIG_TASK_DELAY_ACCT
+struct task_delay_info {
+        spinlock_t      lock;
+        unsigned int    flags;  /* Private per-task flags */
+
+        /* For each stat XXX, add following, aligned appropriately
+         *
+         * struct timespec XXX_start, XXX_end;
+         * u64 XXX_delay;
+         * u32 XXX_count;
+         *
+         * Atomicity of updates to XXX_delay, XXX_count protected by
+         * single lock above (split into XXX_lock if contention is an issue).
+         */
+};
+#endif
+
 enum idle_type
 {
         SCHED_IDLE,
@@ -945,6 +962,9 @@ struct task_struct {
          * cache last used pipe for splice
          */
         struct pipe_inode_info *splice_pipe;
+#ifdef  CONFIG_TASK_DELAY_ACCT
+        struct task_delay_info *delays;
+#endif
 };
 
 static inline pid_t process_group(struct task_struct *tsk)
diff --git a/include/linux/time.h b/include/linux/time.h
index c05f8bb9a323..a5b739967b74 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -71,6 +71,18 @@ extern unsigned long mktime(const unsigned int year, const unsigned int mon,
 extern void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec);
 
 /*
+ * sub = lhs - rhs, in normalized form
+ */
+static inline struct timespec timespec_sub(struct timespec lhs,
+                                                struct timespec rhs)
+{
+        struct timespec ts_delta;
+        set_normalized_timespec(&ts_delta, lhs.tv_sec - rhs.tv_sec,
+                                lhs.tv_nsec - rhs.tv_nsec);
+        return ts_delta;
+}
+
+/*
  * Returns true if the timespec is norm, false if denorm:
  */
 #define timespec_valid(ts) \