From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 9F0101F462 for ; Sat, 15 Jun 2019 19:15:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726614AbfFOTPV (ORCPT ); Sat, 15 Jun 2019 15:15:21 -0400 Received: from injection.crustytoothpaste.net ([192.241.140.119]:60084 "EHLO injection.crustytoothpaste.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726363AbfFOTPV (ORCPT ); Sat, 15 Jun 2019 15:15:21 -0400 Received: from genre.crustytoothpaste.net (unknown [IPv6:2001:470:b978:101:4429:e8a6:430:6b59]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by injection.crustytoothpaste.net (Postfix) with ESMTPSA id EA35A60100; Sat, 15 Jun 2019 19:15:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=crustytoothpaste.net; s=default; t=1560626119; bh=KY6f01F+ZjpWCQCdvKsauxXv0IRZ1gm0/dwPP2ne4Uo=; h=Date:From:To:Cc:Subject:References:Content-Type: Content-Disposition:In-Reply-To:From:Reply-To:Subject:Date:To:CC: Resent-Date:Resent-From:Resent-To:Resent-Cc:In-Reply-To:References: Content-Type:Content-Disposition; b=LHa5t2d6HlbzQ67TM8UQB23QDesZwwNuXhUTxvYa17ySpNS2VtVIeFam5JkuQJ5Gr /rauLetqtrTybzQtOgPFW/OG0Wu2CETfrZL82pITlkSwwdiy9Bt9CqjQJ5totEr3a7 GsRy6SV3YKcKukatbnrUpjpeblIiUJV9S3P/McrayOiNXRO8bPUhB9CHOHKWaPg++u hSa9fKhPIR9EdnW79VErr8ilUnJlMitYdQSCu1kwmvYTmWb9fhaKKT+fzTIvQKHbXJ Naf0PuOIRSs6vfn8Po9YNWBFKiBpDVxpOac7HNiWiAUoPhcfWAjXkCH8/kslRCCEF0 Z40drmzgTnEOhlelhb373VpCw2E++sMv/O2bnJ3ub00mqlcp8eza6X8cm2Jf8jy2OT xqFCFSOjPOf26hUV8zJvlXJKTuW4Ost3YSEOOgzUvDNPE/9zBAEfnYpoSneJlI4pyb MM1vESDiHC+xv7Cz6SNf4UBC+Y3KBBNBIlTayLhbosqxyotcp51 Date: Sat, 15 Jun 2019 19:15:14 +0000 From: "brian m. carlson" To: =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason Cc: Johannes Schindelin via GitGitGadget , git@vger.kernel.org, Junio C Hamano , Johannes Schindelin , SZEDER =?utf-8?B?R8OhYm9y?= , Jeff King , git-packagers@googlegroups.com Subject: Re: Can we just get rid of kwset & obstack in favor of optimistically using PCRE v2 JIT? Message-ID: <20190615191514.GD8616@genre.crustytoothpaste.net> Mail-Followup-To: "brian m. carlson" , =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason , Johannes Schindelin via GitGitGadget , git@vger.kernel.org, Junio C Hamano , Johannes Schindelin , SZEDER =?utf-8?B?R8OhYm9y?= , Jeff King , git-packagers@googlegroups.com References: <87v9x793qi.fsf@evledraar.gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Ilsi/0vOxQ+fn9lZ" Content-Disposition: inline In-Reply-To: <87v9x793qi.fsf@evledraar.gmail.com> X-Machine: Running on genre using GNU/Linux on x86_64 (Linux kernel 4.19.0-5-amd64) User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 127.0.1.1 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org --Ilsi/0vOxQ+fn9lZ Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2019-06-14 at 22:55:17, =C3=86var Arnfj=C3=B6r=C3=B0 Bjarmason wrote: > It seems most packagers build with PCRE v2 now (CC: > git-packagers@). I.e. we'd keep something like compile_fixed_regexp() > (and as an aside just use PCRE's \Q...\E instead of our own escaping). >=20 > We'd have performance regression for platforms that use kwset() now but > don't build pcre2, or where pcre2 jit doesn't work. Does anyone care? I know that there are people shipping newer versions of Git using CentOS 6, which IIRC doesn't ship PCRE 2[0]. Since having to ship your own PCRE is a security maintenance nightmare, it's probably best to leave this at least compatible with non-PCRE 2 systems until November 2020. At that point, I'm happy to drop support for it. If it would work but just be slower with PCRE 1, I'm not too terribly concerned. Let that be an incentive to users to upgrade. Also, as Carlos pointed out, not all platforms will have the JIT support functional, such as OpenBSD, NetBSD, and PaX Linux systems. That may be more of a blocker than the CentOS issue, especially since people run PaX kernels with standard distros. [0] I'm not certain because CentOS 6 Docker images segfault on newer kernels and I'm too lazy to download a live CD image for testing. --=20 brian m. carlson: Houston, Texas, US OpenPGP: https://keybase.io/bk2204 --Ilsi/0vOxQ+fn9lZ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.2.15 (GNU/Linux) iQIzBAABCgAdFiEEX8OngXdrJt+H9ww3v1NdgR9S9osFAl0FQ8IACgkQv1NdgR9S 9ovs5w/+NJhAjpfCjzba55zHh7CEcF1wV9JtriYR8fHchapnPbVC2GM/4zaCqFdB 5o0HibFHVHacSMSp5YTmbeAbmiIhF4n5Vaxk+v2uz0m/u0iuEehxlTEPtM0jZhSc hxhiuGe9HYvnlKNjveWMGD1AWUG92jktgEwxK6qTXD/NB3RN0iFhOyJXP4XNXRrD xeP5XzzsZO43P3heYJBpLTOTJZDsmwMP0nG/tt4chOfAzRIyzn8lLeO4e/Ko5cH2 SLvPC+Swlr8h+oF2KdGnm3VfgJO3xPGJ9k5hYUqKLfWKHsimgFTrRNzOMspzIgaZ 1wrRomX9Hpzi+3xbef1n2awCouq/mnX+9YGwKoOmgFOG6UiolS/Fa0zWEYiyjrl1 4RQO3Dqq9wHVDPa0hyGTWYIkg7JnvqflKObDn4ycrCM1qbpfwhYf4VLO9qgdaLlV dtqcO1v1SqRT0Nm2/df8h9fH6eg3GMjT/RyqLvMCrcC3TwLSX4QVnpKzff3Ju+gu SBY4y1Yy7LDxLHMYN34bvgB7s1XeVu+xoYRyyczS06NbrlEGL+67jePpUzUhje52 YE8CUMizGDzujRe9b4Vtrts5OqCNskeQsOzDsLLL2HhJJqhQJkgqMHzDKiCP8rI5 4Ri9Y1Xr3ByyMwQNzYBEpEKex49DjU8811IMDY1mKGV3ihoZoLk= =Bc7G -----END PGP SIGNATURE----- --Ilsi/0vOxQ+fn9lZ--