From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 37119 invoked by alias); 15 Jun 2018 17:50:21 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 37103 invoked by uid 89); 15 Jun 2018 17:50:20 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-6.9 required=5.0 tests=BAYES_00,GIT_PATCH_2,SPF_PASS autolearn=ham version=3.3.2 spammy=interest X-HELO: mail.efficios.com DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com D91ED22B6BA Date: Fri, 15 Jun 2018 17:50:00 -0000 From: Mathieu Desnoyers To: Florian Weimer Cc: Pavel Machek , carlos , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Thomas Gleixner , linux-kernel , libc-alpha Message-ID: <422468177.14427.1529085017684.JavaMail.zimbra@efficios.com> In-Reply-To: References: <1084280721.10859.1528746558696.JavaMail.zimbra@efficios.com> <31fc101a-295b-067b-1a82-7e9e509fc92f@redhat.com> <305409897.10888.1528747473727.JavaMail.zimbra@efficios.com> <091061df-3482-8762-30e4-feaf3417be11@redhat.com> <417742741.11550.1528821084084.JavaMail.zimbra@efficios.com> <20180614122759.GB8798@amd> <894222691.12973.1528981314012.JavaMail.zimbra@efficios.com> Subject: Re: Restartable Sequences system call merged into Linux MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2018-06/txt/msg00443.txt.bz2 ----- On Jun 15, 2018, at 1:09 AM, Florian Weimer fweimer@redhat.com wrote: > On 06/14/2018 03:01 PM, Mathieu Desnoyers wrote: >> Another alternative would be to somehow let glibc handle the registration, >> perhaps only doing it for applications expressing their interest for rseq. > > That's not really possible. We can't rely on the visibility of symbol > bindings due to lazy binding and hidden visibility. Registration of > intent by other means will not work because if it is done from user > code, some other library may have already launched a thread at this point. > > (It's also a moot point if we want to use restartable sequences in glibc > itself.) Considering that we can expect the glibc memory allocator to benefit from rseq to speed up its memory allocator, this means pretty much any application linked against glibc *will* end up using rseq indirectly. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com