From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43D70C43610 for ; Thu, 22 Nov 2018 01:09:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0779F2075B for ; Thu, 22 Nov 2018 01:09:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=cisco.com header.i=@cisco.com header.b="j7LRlEiC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0779F2075B Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=cisco.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391309AbeKVLqo (ORCPT ); Thu, 22 Nov 2018 06:46:44 -0500 Received: from rcdn-iport-4.cisco.com ([173.37.86.75]:61286 "EHLO rcdn-iport-4.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732372AbeKVLqn (ORCPT ); Thu, 22 Nov 2018 06:46:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=1878; q=dns/txt; s=iport; t=1542848990; x=1544058590; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=bmz3GIx9sS1ehSEvyWkOyb8XtNxhMm31yATQ8Z1tICc=; b=j7LRlEiC8xl9DPrHRWvrKUopFuthTPUf3NDu0ANv/mwBBq099yxvDhl2 M2I4sLobboQ9uLIB/3Nn2qjjfMFXKOQEsA+jw3j+0Z/ZgmvGty3zHhllH b8ZbZAAKCHtHpd6cp+knasoDK8hyjO8FuDcU32dvrtMJq7lkt+0hSkZQ2 E=; X-IronPort-AV: E=Sophos;i="5.56,263,1539648000"; d="scan'208";a="486624729" Received: from rcdn-core-9.cisco.com ([173.37.93.145]) by rcdn-iport-4.cisco.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Nov 2018 01:09:50 +0000 Received: from [10.24.99.63] ([10.24.99.63]) by rcdn-core-9.cisco.com (8.15.2/8.15.2) with ESMTP id wAM19lXN018356; Thu, 22 Nov 2018 01:09:47 GMT Subject: Re: [PATCH v5] kernel/signal: Signal-based pre-coredump notification To: Andrew Morton Cc: Oleg Nesterov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Peter Zijlstra , Arnd Bergmann , "Eric W. Biederman" , Khalid Aziz , Kate Stewart , Helge Deller , Greg Kroah-Hartman , Al Viro , Christian Brauner , Catalin Marinas , Will Deacon , Dave Martin , Mauro Carvalho Chehab , Michal Hocko , Rik van Riel , "Kirill A. Shutemov" , Roman Gushchin , Marcos Paulo de Souza , Dominik Brodowski , Cyrill Gorcunov , Yang Shi , Jann Horn , Kees Cook , x86@kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, "Victor Kamensky (kamensky)" , xe-linux-external@cisco.com, Stefan Strogin , Enke Chen References: <458c04d8-d189-4a26-729a-bb1d1d751534@cisco.com> <7741efa7-a3f8-62a1-ba52-613883164643@cisco.com> <84460a77-a111-404e-4bad-88104a6e246e@cisco.com> <20181026082812.GA10581@redhat.com> <21f678a8-4001-df36-c26e-e96cf203b1b1@cisco.com> <20181029111804.GA24820@redhat.com> <0c197608-3b7e-ffd1-8943-801a60beb917@cisco.com> <20181030164628.GD7643@redhat.com> <20181121163711.2c00316784d221eb1750edb0@linux-foundation.org> From: Enke Chen Message-ID: Date: Wed, 21 Nov 2018 17:09:50 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181121163711.2c00316784d221eb1750edb0@linux-foundation.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Auto-Response-Suppress: DR, OOF, AutoReply X-Outbound-SMTP-Client: 10.24.99.63, [10.24.99.63] X-Outbound-Node: rcdn-core-9.cisco.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Andrew: On 11/21/18 4:37 PM, Andrew Morton wrote: > On Tue, 30 Oct 2018 17:46:29 +0100 Oleg Nesterov wrote: > >> On 10/29, Enke Chen wrote: >>> >>> Reviewed-by: Oleg Nesterov >> >> Hmm. I didn't say this ;) >> >> But OK, feel free to keep this tag. >> >> I do not like this feauture. > > Why is that? > >> But I see no technical problems in this version >> and I never pretented I understand the user-space needs, so I won't argue. > > The changelog appears to spell this all out quite well? Unusually > well, in my experience ;) I also followed up with a little more explanation in the email thread on 10/30/2018: --- As I explained earlier, the primary application is in the area of network high-availability / non-stop-forwarding where early fault notification and early action can help maintain BFD sessions and thus avoid unnecessary disruption to forwarding while the control-plane is recovering. --- BTW, I probably should have pointed out this earlier: BFD stands for "RFC 5880: Bi-directional forwarding detection". > > A couple of things... > > - We'll be looking for a manpage update please. (Search MAINTAINERS > for "manpage") Yes, I will submit a manpage update. Most of the text is already written in the patch description. > > - As it's a linux-specific feature, a test under > tools/testing/selftests would be appropriate. I don't know how much > that work will be. The selftest code was submitted on 10/25/2018: [PATCH] selftests/prctl: selftest for pre-coredump signal notification > Do we have other linux-specific signal extensions which could piggyback onto that? No. There are enough existing signals that an application can choose for this purpose, such as SIGUSR1, SIGUSR1, and any of the RT signals. Thanks. -- Enke