Re: [RFC] Per-thread getrusage

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 28 Jan 2008 12:38:17 +0300 Pavel Emelyanov <xemul@openvz.org> wrote:

> > If the code was using find_task_by_vpid() then OK (I guess).  But it is
> 
> Yup, find_task_by_vpid() will find the proper (i.e. in your namespace) task.
> 
> > looking the tids up in the init_pid_ns.  Which I assume means that if it's
> > in a new namespace and is looking up a sibling thread it will simply fail?
> 
> If it looks in the init_pid_ns, then it can either fail or obtain a task 
> from different namespace. The find_task_by_pid_ns() was intended to be used
> in proc mainly, to get tasks from the namespace pointed by the super-block
> being explored.
> 
> Please excuse my lamentable ignorance, but which code does such things with
> init_pid_ns? I followed the 'per-thread rusage' thread and didn't find any.

From: Vinay Sridhar <vinay@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org, libc-alpha@sourceware.org
Cc: drepper@redhat.com, wli@holomorphy.com, akpm@linux-foundation.org, sripathik@in.ibm.com
Subject: [RFC] Per-thread getrusage
...
+asmlinkage long sys_thread_getrusage(int tid, struct rusage __user *ru)
+{
+	struct task_struct *tsk;
+	tsk = find_task_by_pid(tid);
+	return getrusage(tsk, RUSAGE_THREAD, ru);
+}