From mboxrd@z Thu Jan 1 00:00:00 1970 From: Enke Chen Subject: Re: [PATCH v5] kernel/signal: Signal-based pre-coredump notification Date: Wed, 21 Nov 2018 20:57:31 -0800 Message-ID: <08366d06-9f47-b80e-3662-a84c5107be89@cisco.com> 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> <20181121173341.707a0a869bf16b85f09d75b5@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181121173341.707a0a869bf16b85f09d75b5@linux-foundation.org> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-arch.vger.kernel.org Hi, Andrew: As suggested, I will post them as a patch series (with the same version v5): [PATCH v5 1/2] kernel/signal: Signal-based pre-coredump notification [PATCH v5 2/2] selftests/prctl: selftest for pre-coredump signal notification I have a diff for the manpage as well. I guess that it should be submitted separately from the code. Thanks. -- Enke On 11/21/18 5:33 PM, Andrew Morton wrote: > On Wed, 21 Nov 2018 17:09:50 -0800 Enke Chen wrote: > >> 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". > > I saw that. My point is that your above followup wasn't necessary - > the changelog is clear! > >>> >>> - 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 > > OK, please prepare these as a patch series. > >>> 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. >> > > My point is that if we have previously added any linux-specific signal > expensions then your selftest patch would be an appropriate place where > we could add tests for those features. I'm not saying that you should > add such tests at this time, but please do prepare the selftest as a > thing which tests linux-specific signal extensions in general, not as a > thing which tests pre-coredump signals only. > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rcdn-iport-3.cisco.com ([173.37.86.74]:10109 "EHLO rcdn-iport-3.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732146AbeKVPfK (ORCPT ); Thu, 22 Nov 2018 10:35:10 -0500 Subject: Re: [PATCH v5] kernel/signal: Signal-based pre-coredump notification 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> <20181121173341.707a0a869bf16b85f09d75b5@linux-foundation.org> From: Enke Chen Message-ID: <08366d06-9f47-b80e-3662-a84c5107be89@cisco.com> Date: Wed, 21 Nov 2018 20:57:31 -0800 MIME-Version: 1.0 In-Reply-To: <20181121173341.707a0a869bf16b85f09d75b5@linux-foundation.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: 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 Message-ID: <20181122045731.H7mIDuSBvli0bfJuz7IMKEMVYCi8DbBsY-a8OPWxT4o@z> Hi, Andrew: As suggested, I will post them as a patch series (with the same version v5): [PATCH v5 1/2] kernel/signal: Signal-based pre-coredump notification [PATCH v5 2/2] selftests/prctl: selftest for pre-coredump signal notification I have a diff for the manpage as well. I guess that it should be submitted separately from the code. Thanks. -- Enke On 11/21/18 5:33 PM, Andrew Morton wrote: > On Wed, 21 Nov 2018 17:09:50 -0800 Enke Chen wrote: > >> 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". > > I saw that. My point is that your above followup wasn't necessary - > the changelog is clear! > >>> >>> - 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 > > OK, please prepare these as a patch series. > >>> 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. >> > > My point is that if we have previously added any linux-specific signal > expensions then your selftest patch would be an appropriate place where > we could add tests for those features. I'm not saying that you should > add such tests at this time, but please do prepare the selftest as a > thing which tests linux-specific signal extensions in general, not as a > thing which tests pre-coredump signals only. >