From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2931836-1525370669-2-7932675090294135553 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org', XOriginatingCountry='CA' X-Spam-charsets: plain='utf-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-api-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1525370668; b=WTa9ehKPlth5OAkbQXEvxj2QhSeQW6wwyKQ9uJKVDilHLp5GJn hW57Oc9S3df/aSSCNAishHBCpgOA+JcwEDr5oNStBem6JbYKl+5/pvGe+vQSc9LV 9Pw7YSE/IO/V4Q9O5aEX3cE4cU5eZKLyhikRC0wpdes6ItbaD0Ltx6VvMC3Qfs5N nBnMLVgnEuEkMdHGarlTOGt+ja3cFBirhix3UlbV8Paoup77ySKHM42tvNS8bhWe XeNj8rTOO4cunbiKy/qeDN7w0vnvioaE5Weh58vJbCUGXPS34VAabImuZtmgAUMA J+4G/uOjcpSIpCVOeGwGr/+si+COFdXCKMPA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-type :content-transfer-encoding:sender:list-id; s=fm2; t=1525370668; bh=DRCcyCoav8xl81M1T/GQjgUQGWsARynLol99sYM0bdo=; b=WxxhsSAbkgfR K9mnQW9+Vh71F1tQAk2fKllkj67kaDO8ptTUGny+ivbAXEidLPMaqqOhgG5Vhtik HTqH+etewU+UQpyLbNjYR0z7nzbYCxkqf9du8XX2dT5niIgFj2mIVjvE98etljMm je3sTR8fCYQNCDFBlbf9TuJS7ehGoqzxRgMwcEXECgeMsrP26S2RcQAuu37j5cM9 azycvgWJTr2dohWDMQXdaj/BRvZXcEQ6WCM924ya/lcIoIzpio143RwYb6du/qLi uYSif6Sr9L2MOZU8IEYjQO8tUU+MBlcuZ/5vPAigo2u6PHQXAhbWx6x6fEQ2YF69 2jsbXsCbMw== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=efficios.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=efficios.com header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=efficios.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=efficios.com header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfJXvD5WfbXSO3op/1R/DXaL6XkJloRKVBjuKRV3kN8HJN3C1f4CEBMShqsSfcW8tdYmDJUAV0aIxtaFarKh3uSLateZFtBymuaayiIcPFAjs1/zxQsVJ mMmS9uaqvSIPzrL3eTu5m4fdzolNJVKnsH3g6YP5XgSeISl6M8kRSFZUZy4iSF2oFKREZ/Hxv0C1PobPt10I4DOUX0Xg3Au2Af9TlWHoLuqH+PQFx37kbo9C X-CM-Analysis: v=2.3 cv=E8HjW5Vl c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=FKkrIqjQGGEA:10 a=alcw4SYXYecA:10 a=IkcTkHD0fZMA:10 a=VUJBJC2UJ8kA:10 a=FqpbrowB-PMA:10 a=1XWaLZrsAAAA:8 a=7d_E57ReAAAA:8 a=D19gQVrFAAAA:8 a=VwQbUJbxAAAA:8 a=twcFBZ8WiawN7c8m46cA:9 a=QEXdDO2ut3YA:10 a=x8gzFH9gYPwA:10 a=jhqOcbufqs7Y1TYCrUUU:22 a=W4TVW4IDbPiebHqcZpNg:22 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751195AbeECSE0 (ORCPT ); Thu, 3 May 2018 14:04:26 -0400 Received: from mail.efficios.com ([167.114.142.138]:58178 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751132AbeECSEZ (ORCPT ); Thu, 3 May 2018 14:04:25 -0400 Date: Thu, 3 May 2018 14:04:24 -0400 (EDT) From: Mathieu Desnoyers To: Daniel Colascione Cc: Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Andy Lutomirski , Dave Watson , linux-kernel , linux-api , Paul Turner , Andrew Morton , Russell King , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Hunter , Andi Kleen , Chris Lameter , Ben Maurer , rostedt , Josh Triplett , Linus Torvalds , Catalin Marinas , Will Deacon , Michael Kerrisk , Joel Fernandes Message-ID: <702933118.10410.1525370664578.JavaMail.zimbra@efficios.com> In-Reply-To: References: <20180430224433.17407-1-mathieu.desnoyers@efficios.com> <660904075.9201.1525276988842.JavaMail.zimbra@efficios.com> <1718748931.10084.1525363941807.JavaMail.zimbra@efficios.com> Subject: Re: [RFC PATCH for 4.18 00/14] Restartable Sequences MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.142.138] X-Mailer: Zimbra 8.8.8_GA_2009 (ZimbraWebClient - FF52 (Linux)/8.8.8_GA_2009) Thread-Topic: Restartable Sequences Thread-Index: j2E8hgZac2IxhUNyhqgh0vRIxtvmiA== Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: ----- On May 3, 2018, at 12:22 PM, Daniel Colascione dancol@google.com wrote: > On Thu, May 3, 2018 at 9:12 AM Mathieu Desnoyers < > mathieu.desnoyers@efficios.com> wrote: >> By the way, if we eventually find a way to enhance user-space mutexes in > the >> fashion you describe here, it would belong to another TLS area, and would >> be registered by another system call than rseq. I proposed a more generic >> "TLS area registration" system call a few years ago, but Linus told me he >> wanted a system call that was specific to rseq. If we need to implement >> other use-cases in a TLS area shared between kernel and user-space in a >> similar fashion, the plan is to do it in a distinct system call. > > If we proliferate TLS areas; we'd have to register each one upon thread > creation, adding to the overall thread creation path. There's already a > provision for versioning the TLS area. What's the benefit of splitting the > registration over multiple system calls? See the original discussion thread at https://lkml.org/lkml/2016/4/7/502 Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com