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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 6900DC4363A for ; Mon, 5 Oct 2020 14:12:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 03857205F4 for ; Mon, 5 Oct 2020 14:12:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 03857205F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lwn.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 98A3C6B0070; Mon, 5 Oct 2020 10:12:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 93B046B0071; Mon, 5 Oct 2020 10:12:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 877DB6B0072; Mon, 5 Oct 2020 10:12:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0043.hostedemail.com [216.40.44.43]) by kanga.kvack.org (Postfix) with ESMTP id 5C14C6B0070 for ; Mon, 5 Oct 2020 10:12:17 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id EF4B433CD for ; Mon, 5 Oct 2020 14:12:16 +0000 (UTC) X-FDA: 77338061472.29.food29_49056c2271be Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id C7E6518086CC0 for ; Mon, 5 Oct 2020 14:12:16 +0000 (UTC) X-HE-Tag: food29_49056c2271be X-Filterd-Recvd-Size: 1762 Received: from ms.lwn.net (ms.lwn.net [45.79.88.28]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Mon, 5 Oct 2020 14:12:15 +0000 (UTC) Received: from lwn.net (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ms.lwn.net (Postfix) with ESMTPSA id 423A32E4; Mon, 5 Oct 2020 14:12:12 +0000 (UTC) Date: Mon, 5 Oct 2020 08:12:10 -0600 From: Jonathan Corbet To: Topi Miettinen Cc: Michal Hocko , David Hildenbrand , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: optionally disable brk() Message-ID: <20201005081210.2231e552@lwn.net> In-Reply-To: <7d7b1ac5-d6a7-5e43-8fb8-12b844d7f501@gmail.com> References: <20201002171921.3053-1-toiwoton@gmail.com> <653873ef-2a57-37e0-1ac3-fba763652b35@redhat.com> <2a0f5ade-d770-c36e-50bc-ff0c8e9dacbf@gmail.com> <20201005061248.GN4555@dhcp22.suse.cz> <7d7b1ac5-d6a7-5e43-8fb8-12b844d7f501@gmail.com> Organization: LWN.net MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 5 Oct 2020 11:11:35 +0300 Topi Miettinen wrote: > The point is not to shrink the kernel (it will shrink by one small=20 > function) or get rid of complexity. The point is to disable an inferior= =20 > interface. Memory returned by mmap() is at a random location but with=20 > brk() it is located near the data segment, so the address is more easil= y=20 > predictable. So if your true objective is to get glibc to allocate memory differently, perhaps the right thing to do is to patch glibc? Thanks, jon