Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756239AbYJVKHd (ORCPT ); Wed, 22 Oct 2008 06:07:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754527AbYJVKHN (ORCPT ); Wed, 22 Oct 2008 06:07:13 -0400 Received: from mtagate7.uk.ibm.com ([195.212.29.140]:39766 "EHLO mtagate7.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753513AbYJVKHM (ORCPT ); Wed, 22 Oct 2008 06:07:12 -0400 Subject: Re: [Devel] Re: [PATCH 08/10] Introduce functions to restart a process From: Greg Kurz To: Louis.Rilling@kerlabs.com Cc: Andrey Mirkin , containers@lists.linux-foundation.org, Cedric Le Goater , linux-kernel@vger.kernel.org, Pavel Emelyanov In-Reply-To: <20081022092502.GW15171@hawkmoon.kerlabs.com> References: <1224285098-573-1-git-send-email-major@openvz.org> <1224285098-573-9-git-send-email-major@openvz.org> <48FC4E0C.7050008@fr.ibm.com> <200810221249.55600.major@openvz.org> <20081022092502.GW15171@hawkmoon.kerlabs.com> Content-Type: text/plain Date: Wed, 22 Oct 2008 12:06:19 +0200 Message-Id: <1224669979.4210.15.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 (2.22.3.1-1.fc9) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1339 Lines: 30 On Wed, 2008-10-22 at 11:25 +0200, Louis Rilling wrote: > Do you checkpoint uninterruptible syscalls as well? If only interruptible > syscalls are checkpointed, I'd say that either this syscall uses ERESTARTSYS or > ERESTART_RESTARTBLOCK, and then signal handling code already does the trick, or > this syscall does not restart itself when interrupted, and well, this is life, > userspace just sees -EINTR, which is allowed by the syscall spec. > Actually this is how we checkpoint/migrate tasks in interruptible syscalls in > Kerrighed and this works. > > Louis > I don't know Kerrighed internals but I understand you perform checkpoint with a signal handler. Right ? This approach has a huge benefit: the signal handling code do all the arch dependant stuff to save registers in user memory. -- Gregory Kurz gkurz@fr.ibm.com Software Engineer @ IBM/Meiosys http://www.ibm.com Tel +33 (0)534 638 479 Fax +33 (0)561 400 420 "Anarchy is about taking complete responsibility for yourself." Alan Moore. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/