From owner-svn-src-head@FreeBSD.ORG Fri Dec 5 21:03:56 2008 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D75A91065673; Fri, 5 Dec 2008 21:03:56 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.terabit.net.ua (mail.terabit.net.ua [195.137.202.147]) by mx1.freebsd.org (Postfix) with ESMTP id 7A26F8FC08; Fri, 5 Dec 2008 21:03:56 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from skuns.zoral.com.ua ([91.193.166.194] helo=mail.zoral.com.ua) by mail.terabit.net.ua with esmtps (TLSv1:AES256-SHA:256) (Exim 4.63 (FreeBSD)) (envelope-from ) id 1L8hq4-0006AA-Hq; Fri, 05 Dec 2008 23:03:52 +0200 Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id mB5L3n70094534 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 5 Dec 2008 23:03:49 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.3/8.14.3) with ESMTP id mB5L3nPQ046255; Fri, 5 Dec 2008 23:03:49 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.3/8.14.3/Submit) id mB5L3njG046254; Fri, 5 Dec 2008 23:03:49 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Fri, 5 Dec 2008 23:03:49 +0200 From: Kostik Belousov To: Julian Elischer Message-ID: <20081205210349.GQ2038@deviant.kiev.zoral.com.ua> References: <200812052050.mB5KoOcV072648@svn.freebsd.org> <49399510.2030104@elischer.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="H2kTGx6mr3R59oXC" Content-Disposition: inline In-Reply-To: <49399510.2030104@elischer.org> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: ClamAV version 0.93.3, clamav-milter version 0.93.3 on skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua X-Virus-Scanned: mail.terabit.net.ua 1L8hq4-0006AA-Hq 8c31ab556e3a6c0ec03eeb1f8f4a67fa X-Terabit: YES Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r185647 - in head/sys: kern sys X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 Dec 2008 21:03:57 -0000 --H2kTGx6mr3R59oXC Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Dec 05, 2008 at 12:54:40PM -0800, Julian Elischer wrote: > Konstantin Belousov wrote: > >Author: kib > >Date: Fri Dec 5 20:50:24 2008 > >New Revision: 185647 > >URL: http://svn.freebsd.org/changeset/base/185647 > > > >Log: > > Several threads in a process may do vfork() simultaneously. Then, all > > parent threads sleep on the parent' struct proc until corresponding > > child releases the vmspace. Each sleep is interlocked with proc mutex = of > > the child, that triggers assertion in the sleepq_add(). The assertion > > requires that at any time, all simultaneous sleepers for the channel u= se > > the same interlock. >=20 > We DID have a thread_single() in the fork code so that > only one thread would proceed through the fork itself at a time. > However it was removed last year as it proved to be a problem in some=20 > cases. Maybe we need to look at replacing it in some way. Yes, I know, and I considered restoring conditional single-threading for the vfork(). But it would immediately bring back all NFS client problems, associated with this (at least sleeping with vnode lock held and nfsbiod creation deadlocks). This is a second problem caused by removal of the single-threading. Nonetheless, I think that your change was right, and we shall just fix a corner cases. --H2kTGx6mr3R59oXC Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkk5lzQACgkQC3+MBN1Mb4jDrwCfSHI2WPu10vxN2JOd4DKcCCvI P9IAnjw6MosZ2AjszKnkkv/TER0JlOwi =jl/g -----END PGP SIGNATURE----- --H2kTGx6mr3R59oXC--