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([2001:b07:6468:f312:9af8:e5f5:7516:fa89]) by smtp.googlemail.com with ESMTPSA id ky16-20020a170907779000b00730a73cbe08sm2246142ejc.169.2022.08.10.05.35.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 10 Aug 2022 05:35:58 -0700 (PDT) Message-ID: Date: Wed, 10 Aug 2022 14:35:55 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.12.0 Subject: Re: [PATCH 1/2] KVM: selftests: Make rseq compatible with glibc-2.35 Content-Language: en-US To: Mathieu Desnoyers , Gavin Shan Cc: Sean Christopherson , shuah , Florian Weimer , kvmarm , KVM list , linux-kselftest , linux-kernel , maz , oliver upton , andrew jones , yihyu , shan gavin References: <20220809060627.115847-1-gshan@redhat.com> <7844e3fa-e49e-de75-e424-e82d3a023dd6@redhat.com> <87o7wtnay6.fsf@oldenburg.str.redhat.com> <616d4de6-81f6-9d14-4e57-4a79fec45690@redhat.com> <797306043.114963.1660047714774.JavaMail.zimbra@efficios.com> <1014177394.115022.1660052656961.JavaMail.zimbra@efficios.com> <8c1f33b4-a5a1-fcfa-4521-36253ffa22c8@redhat.com> <1316061904.375.1660134559269.JavaMail.zimbra@efficios.com> From: Paolo Bonzini In-Reply-To: <1316061904.375.1660134559269.JavaMail.zimbra@efficios.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On 8/10/22 14:29, Mathieu Desnoyers wrote: >> - By design, selftests/rseq and selftests/kvm are parallel. It's going to >> introduce >> unnecessary dependency for selftests/kvm to use selftests/rseq/librseq.so. To >> me, >> it makes the maintainability even harder. > In terms of build system, yes, selftests/rseq and selftests/kvm are side-by-side, > and I agree it is odd to have a cross-dependency. > > That's where moving rseq.c to tools/lib/ makes sense. > >> - What selftests/kvm needs is rseq-thread-pointer.h, which accounts for ~5% of >> functionalities, provided by selftests/rseq/librseq.so. > I've never seen this type of argument used to prevent using a library before, except > on extremely memory-constrained devices, which is not our target here. I agree. To me, the main argument against moving librseq to tools/lib is a variant of the build-system argument, namely that recursive Make sucks[1] and selftests/kvm right now does not use tools/lib. So, for a single-file library, it may be simply not worth the hassle. On the other hand, if "somebody else" does the work, I would have no problem with having selftests/kvm depend on tools/lib, not at all. Thanks, Paolo [1] Kbuild is a marvel that makes it work, but it works because there are no such cross-subdirectory dependencies and anyway tools/testing/selftests does not use Kbuild.