From owner-svn-src-all@FreeBSD.ORG Thu Sep 2 08:11:43 2010 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A9AD41065751; Thu, 2 Sep 2010 08:11:43 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id 453EF8FC1E; Thu, 2 Sep 2010 08:11:42 +0000 (UTC) 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 o828BaSo004481 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 2 Sep 2010 11:11:36 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4) with ESMTP id o828Bait056049; Thu, 2 Sep 2010 11:11:36 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4/Submit) id o828BaYt056048; Thu, 2 Sep 2010 11:11:36 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Thu, 2 Sep 2010 11:11:36 +0300 From: Kostik Belousov To: David Xu Message-ID: <20100902081136.GG2396@deviant.kiev.zoral.com.ua> References: <201009010218.o812IX5G048257@svn.freebsd.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="DNWMrkyqDUV26QiQ" Content-Disposition: inline In-Reply-To: <201009010218.o812IX5G048257@svn.freebsd.org> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-2.2 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_50, DNS_FROM_OPENWHOIS autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r212076 - head/lib/libthr/thread X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 Sep 2010 08:11:43 -0000 --DNWMrkyqDUV26QiQ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Sep 01, 2010 at 02:18:33AM +0000, David Xu wrote: > Author: davidxu > Date: Wed Sep 1 02:18:33 2010 > New Revision: 212076 > URL: http://svn.freebsd.org/changeset/base/212076 >=20 > Log: > Add signal handler wrapper, the reason to add it becauses there are > some cases we want to improve: > 1) if a thread signal got a signal while in cancellation point, > it is possible the TDP_WAKEUP may be eaten by signal handler > if the handler called some interruptibly system calls. > 2) In signal handler, we want to disable cancellation. > 3) When thread holding some low level locks, it is better to > disable signal, those code need not to worry reentrancy, > sigprocmask system call is avoided because it is a bit expensive. > The signal handler wrapper works in this way: > 1) libthr installs its signal handler if user code invokes sigaction > to install its handler, the user handler is recorded in internal > array. > 2) when a signal is delivered, libthr's signal handler is invoke, > libthr checks if thread holds some low level lock or is in critical > region, if it is true, the signal is buffered, and all signals are > masked, once the thread leaves critical region, correct signal > mask is restored and buffered signal is processed. > 3) before user signal handler is invoked, cancellation is temporarily > disabled, after user signal handler is returned, cancellation state > is restored, and pending cancellation is rescheduled. > +static void > +thr_sighandler(int sig, siginfo_t *info, void *_ucp) > +{ > + if ((actp->sa_flags & SA_SIGINFO) !=3D 0) > + (*(sigfunc))(sig, info, ucp); > + else { > + ((ohandler)(*sigfunc))( > + sig, info->si_code, (struct sigcontext *)ucp, > + info->si_addr, (__sighandler_t *)sigfunc); > + } I do not think this is very important, but freebsd old-style signal handler fourth argument is usually the faulted %eip value. This is most likely irrelevant for any source that is linked with libthr.so new enough to contain this change. --DNWMrkyqDUV26QiQ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkx/XDgACgkQC3+MBN1Mb4iwWQCgjjl5Xxc5WHgKeHE+VJ5cpPpu vmAAn1Ez/iXX4u9dZCd+mU7aJ9k0+Jhu =42+D -----END PGP SIGNATURE----- --DNWMrkyqDUV26QiQ--