From owner-freebsd-stable@FreeBSD.ORG Tue Apr 1 13:57:13 2014 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 8483373F; Tue, 1 Apr 2014 13:57:13 +0000 (UTC) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 5B30A6E5; Tue, 1 Apr 2014 13:57:13 +0000 (UTC) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id EBB46B918; Tue, 1 Apr 2014 09:57:11 -0400 (EDT) From: John Baldwin To: freebsd-hackers@freebsd.org Subject: Re: Process handlers, and zombies, or preap(1) Date: Tue, 1 Apr 2014 09:41:33 -0400 User-Agent: KMail/1.13.5 (FreeBSD/8.4-CBSD-20130906; KDE/4.5.5; amd64; ; ) References: <26dbb84bafaf0114cb75c3fbe060d412.authenticated@ultimatedns.net> In-Reply-To: <26dbb84bafaf0114cb75c3fbe060d412.authenticated@ultimatedns.net> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201404010941.33741.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Tue, 01 Apr 2014 09:57:12 -0400 (EDT) Cc: freebsd-hackers , freebsd-stable , Chris H X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Apr 2014 13:57:13 -0000 On Monday, March 31, 2014 4:06:43 pm Chris H wrote: > Greetings, > I'm evaluating/experimenting on releng_9. The install, and now > custom kernel have noting exotic, or anything out of the ordinary. > top(1), and ps(1) indicate a (1) zombie, or process. On > my releng_8 systems, when I occasionally encounter one of these, > they soon disappear (are reaped) from the process table. While I > have not investigated this far enough on both versions to determine > whether the parent process reaped the child on the releng_8 systems, > and the parent on releng_9 is simply an irresponsible parent, eg; > a different parent. Before I do, I was wondering if there was any > specific difference between the 2 versions that might cause better > handling of such situations. While I recognize that resource > starvation is HIGHLY unlikely, except by perhaps a rouge parent > spawning multitudes of zombies. I thought it might be useful for > "housekeeping" to 1) provide a process table housekeeper (zombie > reaper), or 2) create a system utility/command like SunOS/OpenSolaris > has; preap(1). > > http://www.freebsd.org/cgi/man.cgi?query=preap&manpath=SunOS+5.10 > > Thank you for your time, and consideration. Nothing is different with child processes in 9 vs 8. It is most likely a misbehaving parent (or the parent is stuck or hung). -- John Baldwin