From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 188BCC433E4 for ; Tue, 28 Jul 2020 09:47:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFD3F207E8 for ; Tue, 28 Jul 2020 09:47:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728235AbgG1Jrc (ORCPT ); Tue, 28 Jul 2020 05:47:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48532 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728050AbgG1Jrc (ORCPT ); Tue, 28 Jul 2020 05:47:32 -0400 X-Greylist: delayed 366 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 28 Jul 2020 02:47:32 PDT Received: from mout-p-202.mailbox.org (mout-p-202.mailbox.org [IPv6:2001:67c:2050::465:202]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 24775C061794; Tue, 28 Jul 2020 02:47:32 -0700 (PDT) Received: from smtp1.mailbox.org (smtp1.mailbox.org [IPv6:2001:67c:2050:105:465:1:1:0]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by mout-p-202.mailbox.org (Postfix) with ESMTPS id 4BGBWj2tvzzQlKZ; Tue, 28 Jul 2020 11:41:21 +0200 (CEST) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp1.mailbox.org ([80.241.60.240]) by spamfilter02.heinlein-hosting.de (spamfilter02.heinlein-hosting.de [80.241.56.116]) (amavisd-new, port 10030) with ESMTP id mL45Y320Mr-I; Tue, 28 Jul 2020 11:41:17 +0200 (CEST) Date: Tue, 28 Jul 2020 19:41:09 +1000 From: Aleksa Sarai To: "Eric W. Biederman" Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Kees Cook , Pavel Machek , "Rafael J. Wysocki" , linux-fsdevel@vger.kernel.org, Oleg Nesterov , linux-pm@vger.kernel.org Subject: Re: [RFC][PATCH] exec: Freeze the other threads during a multi-threaded exec Message-ID: <20200728092359.jrv7ygt6dwktwsgp@yavin.dot.cyphar.com> References: <87h7tsllgw.fsf@x220.int.ebiederm.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="ifgp4clg667prhsz" Content-Disposition: inline In-Reply-To: <87h7tsllgw.fsf@x220.int.ebiederm.org> X-MBO-SPAM-Probability: 0 X-Rspamd-Score: -4.89 / 15.00 / 15.00 X-Rspamd-Queue-Id: E1EE11837 X-Rspamd-UID: 106a35 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org --ifgp4clg667prhsz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2020-07-27, Eric W. Biederman wrote: > To the best of my knowledge processes with more than one thread > calling exec are not common, and as all of the threads will be killed > by exec there does not appear to be any useful work a thread can > reliably do during exec. Every Go program which calls exec (this includes runc, Docker, LXD, Kubernetes, et al) fills the niche of "multi-threaded program that calls exec" -- all Go programs are multi-threaded and there's no way of disabling this. This will most likely cause pretty bad performance regression for basically all container workloads. --=20 Aleksa Sarai Senior Software Engineer (Containers) SUSE Linux GmbH --ifgp4clg667prhsz Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQSxZm6dtfE8gxLLfYqdlLljIbnQEgUCXx/ysgAKCRCdlLljIbnQ EkKKAQDoy8ZD4VcTpwNYsy7hTgaSyJYCrr3BEVWWGgivWDOsTAD/YSG2mqdY6Xxb /MSwhLo3kjae0B+Zbr6HVENFaTzZjgc= =1hzK -----END PGP SIGNATURE----- --ifgp4clg667prhsz--