--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/linux/delayacct.h	Sun Jan 11 20:20:11 2009 +0100
@@ -0,0 +1,153 @@
+/* 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>
+#include <linux/taskstats_kern.h>
+
+/*
+ * Per-task flags relevant to delay accounting
+ * maintained privately to avoid exhausting similar flags in sched.h:PF_*
+ * Used to set current->delays->flags
+ */
+#define DELAYACCT_PF_SWAPIN	0x00000001	/* I am doing a swapin */
+#define DELAYACCT_PF_BLKIO	0x00000002	/* I am waiting on IO */
+
+#ifdef CONFIG_TASK_DELAY_ACCT
+
+extern int delayacct_on;	/* Delay accounting turned on/off */
+extern struct kmem_cache *delayacct_cache;
+extern void delayacct_init(void);
+extern void __delayacct_tsk_init(struct task_struct *);
+extern void __delayacct_tsk_exit(struct task_struct *);
+extern void __delayacct_blkio_start(void);
+extern void __delayacct_blkio_end(void);
+extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
+extern __u64 __delayacct_blkio_ticks(struct task_struct *);
+extern void __delayacct_freepages_start(void);
+extern void __delayacct_freepages_end(void);
+
+static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
+{
+	if (p->delays)
+		return (p->delays->flags & DELAYACCT_PF_BLKIO);
+	else
+		return 0;
+}
+
+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 (delayacct_on)
+		__delayacct_tsk_init(tsk);
+}
+
+/* Free tsk->delays. Called from bad fork and __put_task_struct
+ * where there's no risk of tsk->delays being accessed elsewhere
+ */
+static inline void delayacct_tsk_free(struct task_struct *tsk)
+{
+	if (tsk->delays)
+		kmem_cache_free(delayacct_cache, tsk->delays);
+	tsk->delays = NULL;
+}
+
+static inline void delayacct_blkio_start(void)
+{
+	delayacct_set_flag(DELAYACCT_PF_BLKIO);
+	if (current->delays)
+		__delayacct_blkio_start();
+}
+
+static inline void delayacct_blkio_end(void)
+{
+	if (current->delays)
+		__delayacct_blkio_end();
+	delayacct_clear_flag(DELAYACCT_PF_BLKIO);
+}
+
+static inline int delayacct_add_tsk(struct taskstats *d,
+					struct task_struct *tsk)
+{
+	if (!delayacct_on || !tsk->delays)
+		return 0;
+	return __delayacct_add_tsk(d, tsk);
+}
+
+static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
+{
+	if (tsk->delays)
+		return __delayacct_blkio_ticks(tsk);
+	return 0;
+}
+
+static inline void delayacct_freepages_start(void)
+{
+	if (current->delays)
+		__delayacct_freepages_start();
+}
+
+static inline void delayacct_freepages_end(void)
+{
+	if (current->delays)
+		__delayacct_freepages_end();
+}
+
+#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_free(struct task_struct *tsk)
+{}
+static inline void delayacct_blkio_start(void)
+{}
+static inline void delayacct_blkio_end(void)
+{}
+static inline int delayacct_add_tsk(struct taskstats *d,
+					struct task_struct *tsk)
+{ return 0; }
+static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
+{ return 0; }
+static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
+{ return 0; }
+static inline void delayacct_freepages_start(void)
+{}
+static inline void delayacct_freepages_end(void)
+{}
+
+#endif /* CONFIG_TASK_DELAY_ACCT */
+
+#endif