From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: John Wiegley Newsgroups: gmane.emacs.devel Subject: Re: Removal of unexec support from glibc malloc Date: Mon, 18 Jan 2016 15:45:05 -0800 Message-ID: References: <569CDB81.6040600@redhat.com> <569D6B1E.6020002@emvision.com> Reply-To: John Wiegley NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" X-Trace: ger.gmane.org 1453160744 2458 80.91.229.3 (18 Jan 2016 23:45:44 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 18 Jan 2016 23:45:44 +0000 (UTC) Cc: emacs-devel@gnu.org To: Ali Bahrami Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Jan 19 00:45:37 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1aLJUO-0001k8-6I for ged-emacs-devel@m.gmane.org; Tue, 19 Jan 2016 00:45:36 +0100 Original-Received: from localhost ([::1]:34217 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aLJUN-0006S9-Hi for ged-emacs-devel@m.gmane.org; Mon, 18 Jan 2016 18:45:35 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:42223) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aLJUA-0006S2-7t for emacs-devel@gnu.org; Mon, 18 Jan 2016 18:45:23 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aLJU5-0000jD-Nf for emacs-devel@gnu.org; Mon, 18 Jan 2016 18:45:22 -0500 Original-Received: from mail-pa0-x22e.google.com ([2607:f8b0:400e:c03::22e]:35177) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aLJU5-0000j8-GQ for emacs-devel@gnu.org; Mon, 18 Jan 2016 18:45:17 -0500 Original-Received: by mail-pa0-x22e.google.com with SMTP id ho8so180084167pac.2 for ; Mon, 18 Jan 2016 15:45:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:in-reply-to:date:message-id:references :user-agent:reply-to:mail-followup-to:mime-version:content-type; bh=DzN5On16xny6QqqjqW8BXlNNX0n4FjoJEKQGLQ8XCKg=; b=vNykUN9BN5VWJEfjhUthsrRFiiwwggUU3jDNDLJHvdzPUQUZd7yHQT6Vup4iVtzOu6 hSCLAwCL9XLZRTeLYc5xL/qdq2Mkq+xZPsdzL8Ej30a9g/YtrqTBRrrfbKzZ6+QqHVh+ lwnpjqZDpc3EodXX2h3rIuGo+R6WAWbatctHrWmO51lZg232uZ++0xYyupJUOtZgBI/l VSNLADR2PXIF8E1SxsKbiOnUVZwxsKldwpOG49XWmMofhBtt3gpHbQW7Gi0tStOt/RZw U8bZ5A0sUf+iBgofySldp1y0IonRFm/nNWBANRi7M2wzbf1JNJ2IK7gf3tSBkU5rCzeB YUGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:in-reply-to:date:message-id :references:user-agent:reply-to:mail-followup-to:mime-version :content-type; bh=DzN5On16xny6QqqjqW8BXlNNX0n4FjoJEKQGLQ8XCKg=; b=Zc/6M7z+ZBxDeQ4JUo+2FCpcpxSACFXV58UmJchvIz1Pb+I2uBucQXpvvR6SXvdiiY TH/YjN2Mpn0GcndEjXiYtW5DJ+ehrfUaTM4vMLFnFqYH1YXMW/UT6AfW7NcYH2G0E4Zr Ju9E6zYPmKnQPiFI/cARTGpc4ov3Yw6H8iA+4k95PhyvUv423MQ7DbuY1FERR7FNDFI4 +ml4/DfjSxSKGBb0NPb79qXedvkoFBmccIp91JnJ1t0litBb+szWGKw5dRYACXchIgdv eRDwN7SKnz7YgOKVJJQxz/QCPHAu5vsQH3weGL/h8GYcR9ojthU64uTuxI5f7IgPC7md vTug== X-Gm-Message-State: ALoCoQkS4xclDV4CvKCtZQ+FPGZLbNw+ankSdkQIRrqgxMQdaukcHVFji2ccXFZzLTJ0rHKnnRABWFcvFa/KZJ8XUOpPYvMn6A== X-Received: by 10.66.63.104 with SMTP id f8mr40348550pas.41.1453160716644; Mon, 18 Jan 2016 15:45:16 -0800 (PST) Original-Received: from Vulcan.local (76-234-68-79.lightspeed.frokca.sbcglobal.net. [76.234.68.79]) by smtp.gmail.com with ESMTPSA id 26sm7833647pfo.55.2016.01.18.15.45.15 (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 18 Jan 2016 15:45:15 -0800 (PST) X-Google-Original-From: "John Wiegley" Original-Received: by Vulcan.local (Postfix, from userid 501) id 39025124C8240; Mon, 18 Jan 2016 15:45:15 -0800 (PST) In-Reply-To: <569D6B1E.6020002@emvision.com> (Ali Bahrami's message of "Mon, 18 Jan 2016 15:45:50 -0700") User-Agent: Gnus/5.130014 (Ma Gnus v0.14) Emacs/24.5 (darwin) Mail-Followup-To: Ali Bahrami , emacs-devel@gnu.org X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2607:f8b0:400e:c03::22e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:198317 Archived-At: --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable >>>>> Ali Bahrami writes: > Unexec is complicated, and it is a problem for alternative non-brk based > mallocs, or ASLR. One of the strong design points of emacs is its use of a > minimal and simple C core, with the system largely written in lisp. Losing > unexec would leave an even simpler core. > Before you fight to to save unexec, I'd encourage you to measure the impa= ct, > and see if it still matters. If it does, then it would be worthwhile to > consider other means for getting those bytes into memory quickly that don= 't > involve second guessing object layout, memory allocation, and process > layout. Speaking as a linker guy, linking is only going to get more dynam= ic, > and more complex, going forward. You might be glad, down the road, to be = out > of that game. > That's not to say that John's concerns above aren't reasonable. This is b= ig > enough that you don't want to force it, but perhaps it's time to start > considering alternatives. I agree with what you're saying. Several voices have already voiced that we= 'd like to move away from the complexity of "being in the malloc business" (thanks, Paul). Now I'd like to know what it will take to get us there. =2D-=20 John Wiegley GPG fingerprint =3D 4710 CF98 AF9B 327B B80F http://newartisans.com 60E1 46C4 BD1A 7AC1 4BA2 --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQGcBAEBCgAGBQJWnXkBAAoJEMFE2PTxn+YwowsMAKX2CGNX6ug82z/61Px1FiyP wbic0rbZglCvALxUzEse1MOES0gmYPq4P1wtjchVO5pUgHXw6yuE6wRJ95Da3nyq /H6o0s+6Swt8Sf4Ugi4I31KPXaq2arzbQ1C5i5wPdifpZK8uYsyhDlo4v86sxGAa PeBw3cGyOJEFgUKAkr5+9VIksQYBhdRW+EEp8MhbynAxkrLiUQfQWWwCsKSGDTOz HlV3vPet504+Cw7Ja4EVOv16bShzzAhO8GaRORYeFeKCfGwC1Z79VbodrlMJDI1h 6djbItPJN2pb4k9V9O0NICVK0DKT3pqpI2srTF4kaNYcuZQ7qSdSQ8m4lPecCXwp PSjMuENBxHGTvUOJiYZjjhDgWfICxVK7Y0vcGpZmOXVpsmWzCTy8OzODb5g3QZ2R kfWP4GewwTcoBR7CoQgwxIUiqP9prgQidK3ll/kGDXMr4X17ETsVNHik7Tk3IP+x 6WJCq6lCCDPkVfFqAQCCoJjllnkHdpIAcS+Gk2/hlw== =Gp8P -----END PGP SIGNATURE----- --=-=-=--