Hi all,
I'm writing a module that can do a dynamic isolcpus at run time. This is
much easier to do in the kernel than in userspace. In order to do this,
I need to iterate over all tasks in the system but I could not find a
way to do this from a module.
So instead of exporting the tasklist_lock (and opening up a great big
can of worms), I wrote this utility function that will allow a module to
iterate some function over all tasks in the system.
Comments and flames welcome.
Signed-off-by: Steven Rostedt <[email protected]>
Index: linux-2.6.21.6-rt21/kernel/sched.c
===================================================================
--- linux-2.6.21.6-rt21.orig/kernel/sched.c
+++ linux-2.6.21.6-rt21/kernel/sched.c
@@ -7065,6 +7065,31 @@ void normalize_rt_tasks(void)
#endif /* CONFIG_MAGIC_SYSRQ */
+/**
+ * on_each_task - run a function on every task.
+ * @func - function to call on the task
+ * @data - data to pass in to func.
+ *
+ * Iterate a function over all tasks in the system.
+ */
+void on_each_task(int(*func)(struct task_struct *t, void *d), void *data)
+{
+ struct task_struct *g, *p;
+
+ read_lock(&tasklist_lock);
+
+ do_each_thread(g, p) {
+
+ /* do_each_thread is a double loop! */
+ if (func(p, data))
+ goto out;
+
+ } while_each_thread(g, p);
+ out:
+ read_unlock(&tasklist_lock);
+}
+EXPORT_SYMBOL_GPL(on_each_task);
+
#ifdef CONFIG_IA64
/*
* These functions are only useful for the IA64 MCA handling.
Index: linux-2.6.21.6-rt21/include/linux/sched.h
===================================================================
--- linux-2.6.21.6-rt21.orig/include/linux/sched.h
+++ linux-2.6.21.6-rt21/include/linux/sched.h
@@ -2079,6 +2079,8 @@ extern int sched_create_sysfs_power_savi
extern void normalize_rt_tasks(void);
+extern void on_each_task(int(*func)(struct task_struct *t, void *d), void *data);
+
#ifdef CONFIG_TASK_XACCT
static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
{
-
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