1 files changed, 87 insertions, 0 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
new file mode 100644
index 000000000000..fbf7f2284952
--- /dev/null
+++ b/kernel/delayacct.c
@@ -0,0 +1,87 @@
+/* delayacct.c - 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 would 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.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/sysctl.h>
+#include <linux/delayacct.h>
+
+int delayacct_on __read_mostly;	/* Delay accounting turned on/off */
+kmem_cache_t *delayacct_cache;
+
+static int __init delayacct_setup_enable(char *str)
+{
+	delayacct_on = 1;
+	return 1;
+}
+__setup("delayacct", delayacct_setup_enable);
+
+void delayacct_init(void)
+{
+	delayacct_cache = kmem_cache_create("delayacct_cache",
+					sizeof(struct task_delay_info),
+					0,
+					SLAB_PANIC,
+					NULL, NULL);
+	delayacct_tsk_init(&init_task);
+}
+
+void __delayacct_tsk_init(struct task_struct *tsk)
+{
+	tsk->delays = kmem_cache_zalloc(delayacct_cache, SLAB_KERNEL);
+	if (tsk->delays)
+		spin_lock_init(&tsk->delays->lock);
+}
+
+void __delayacct_tsk_exit(struct task_struct *tsk)
+{
+	kmem_cache_free(delayacct_cache, tsk->delays);
+	tsk->delays = NULL;
+}
+
+/*
+ * Start accounting for a delay statistic using
+ * its starting timestamp (@start)
+ */
+
+static inline void delayacct_start(struct timespec *start)
+{
+	do_posix_clock_monotonic_gettime(start);
+}
+
+/*
+ * Finish delay accounting for a statistic using
+ * its timestamps (@start, @end), accumalator (@total) and @count
+ */
+
+static void delayacct_end(struct timespec *start, struct timespec *end,
+				u64 *total, u32 *count)
+{
+	struct timespec ts;
+	s64 ns;
+
+	do_posix_clock_monotonic_gettime(end);
+	ts = timespec_sub(*end, *start);
+	ns = timespec_to_ns(&ts);
+	if (ns < 0)
+		return;
+
+	spin_lock(&current->delays->lock);
+	*total += ns;
+	(*count)++;
+	spin_unlock(&current->delays->lock);
+}
+