[PATCH] Add timestamp field to process events

This adds a timestamp field to the events sent via the process event
connector.  The timestamp allows listeners to accurately account the
duration(s) between a process' events and offers strong means with which
to determine the order of events with respect to a given task while also
avoiding the addition of per-task data.

This alters the size and layout of the event structure and hence would
break compatibility if process events connector as it stands in 2.6.15-rc2
were released as a mainline kernel.
Signed-off-by: NMatt Helsley <matthltc@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/connector/cn_proc.c

@@ -56,6 +56,7 @@ void proc_fork_connector(struct task_struct *task)
 	msg = (struct cn_msg*)buffer;
 	ev = (struct proc_event*)msg->data;
 	get_seq(&msg->seq, &ev->cpu);
+	getnstimestamp(&ev->timestamp);
 	ev->what = PROC_EVENT_FORK;
 	ev->event_data.fork.parent_pid = task->real_parent->pid;
 	ev->event_data.fork.parent_tgid = task->real_parent->tgid;
@@ -81,6 +82,7 @@ void proc_exec_connector(struct task_struct *task)
 	msg = (struct cn_msg*)buffer;
 	ev = (struct proc_event*)msg->data;
 	get_seq(&msg->seq, &ev->cpu);
+	getnstimestamp(&ev->timestamp);
 	ev->what = PROC_EVENT_EXEC;
 	ev->event_data.exec.process_pid = task->pid;
 	ev->event_data.exec.process_tgid = task->tgid;
@@ -114,6 +116,7 @@ void proc_id_connector(struct task_struct *task, int which_id)
 	} else
 	     	return;
 	get_seq(&msg->seq, &ev->cpu);
+	getnstimestamp(&ev->timestamp);
 
 	memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 	msg->ack = 0; /* not used */
@@ -133,6 +136,7 @@ void proc_exit_connector(struct task_struct *task)
 	msg = (struct cn_msg*)buffer;
 	ev = (struct proc_event*)msg->data;
 	get_seq(&msg->seq, &ev->cpu);
+	getnstimestamp(&ev->timestamp);
 	ev->what = PROC_EVENT_EXIT;
 	ev->event_data.exit.process_pid = task->pid;
 	ev->event_data.exit.process_tgid = task->tgid;
@@ -165,6 +169,7 @@ static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 	msg = (struct cn_msg*)buffer;
 	ev = (struct proc_event*)msg->data;
 	msg->seq = rcvd_seq;
+	getnstimestamp(&ev->timestamp);
 	ev->cpu = -1;
 	ev->what = PROC_EVENT_NONE;
 	ev->event_data.ack.err = err;

include/linux/cn_proc.h

@@ -26,6 +26,7 @@
 #define CN_PROC_H
 
 #include <linux/types.h>
+#include <linux/time.h>
 #include <linux/connector.h>
 
 /*
@@ -65,6 +66,7 @@ struct proc_event {
 		PROC_EVENT_EXIT = 0x80000000
 	} what;
 	__u32 cpu;
+	struct timespec timestamp;
 	union { /* must be last field of proc_event struct */
 		struct {
 			__u32 err;