From owner-freebsd-hackers@FreeBSD.ORG  Thu Aug  2 02:25:08 2012
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id E5C421065673
	for <freebsd-hackers@freebsd.org>; Thu,  2 Aug 2012 02:25:08 +0000 (UTC)
	(envelope-from listlog2011@gmail.com)
Received: from freefall.freebsd.org (freefall.freebsd.org
	[IPv6:2001:4f8:fff6::28])
	by mx1.freebsd.org (Postfix) with ESMTP id D0D9B8FC0C;
	Thu,  2 Aug 2012 02:25:08 +0000 (UTC)
Received: from [127.0.0.1] (localhost [127.0.0.1])
	by freefall.freebsd.org (8.14.5/8.14.5) with ESMTP id q722P7PJ046977;
	Thu, 2 Aug 2012 02:25:07 GMT (envelope-from listlog2011@gmail.com)
Message-ID: <5019E500.8060105@gmail.com>
Date: Thu, 02 Aug 2012 10:25:04 +0800
From: David Xu <listlog2011@gmail.com>
User-Agent: Mozilla/5.0 (Windows NT 6.1;
	rv:14.0) Gecko/20120713 Thunderbird/14.0
MIME-Version: 1.0
To: Daniel Rudy <dr2867@pacbell.net>
References: <5019E209.50109@pacbell.net>
In-Reply-To: <5019E209.50109@pacbell.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Cc: freebsd-hackers@freebsd.org
Subject: Re: Enumerating sleeping threads
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
Reply-To: davidxu@freebsd.org
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 02 Aug 2012 02:25:09 -0000

On 2012/8/2 10:12, Daniel Rudy wrote:
> Hello,
>
> What is the best way to enumerate the sleeping threads via
> sleepqueue(9)?  Furthermore, when enumerating the threads that are on
> the run queue, what locks are needed, if any?
sleepqueue hash bucket is private data structure in subr_sleepqueue.c, I 
think you
can not access it outside of the file.
One way to enumerate the sleeping threads is iterating all threads in 
the system,
and check their states.  proc.h contains two macros:
FOREACH_PROC_IN_SYSTEM
FOREACH_THREAD_IN_PROC

To access thread state, you should use thread lock,  call thread_lock()
and thread_unlock(). thread lock is not fixed, it might be sleep-queue's 
spinlock
or per-cpu runqueue lock, there even is a blocked spin-lock for 
intermediate state
change.

> Thank you.
>