Received: by 2002:a05:6a10:22f:0:0:0:0 with SMTP id 15csp1496377pxk; Fri, 2 Oct 2020 10:56:05 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxwSWwHwly/Mvby102xrV6PN7mW2qzcSKH/lMHC/6/GMthlnBaER+qbA5Tn0UVVjZ6Kd/tG X-Received: by 2002:a50:8e58:: with SMTP id 24mr3767857edx.226.1601661365164; Fri, 02 Oct 2020 10:56:05 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1601661365; cv=none; d=google.com; s=arc-20160816; b=gGz4QuwKQX9sq0fNzmqsd6UGX0459DShNpkMs4hrAiNoGlRNJDajb/uIS3O+Qpd24j ul1zW+JsHlD2y7YQ+v6i9bITnBkQekanwX1REVamRcCWW8c6rXQIj3gB22l1pHEf2k1T H8Vh5VXjSFnmb/xKGfpd68nN1zOq4lMit3KdtAPMP+1M79hvUVe99pHsZRvbwwXNoAhu EMd1xcLs1eu1mHtyEb+Kvf7UAwCMu9+sprkejqgzHV85jUqf6wGNyUhaeTQMUbVa61JE +u1mvzpu2RKdc0n/gfqw1gtwzvPOQ2L6ICROn/dXjgPqlJNcGftTIkQPuXapXnovtrCn k6Xw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:content-language :in-reply-to:mime-version:user-agent:date:message-id:organization :autocrypt:from:references:to:subject:dkim-signature; bh=UYhZcO1NLSMAx4sk89Nhzce3JSq4NgIfHV17KuBrZ9s=; b=cV+WtmdjjHCp4A+gGvURK1mqpquPN0p7orhwAS9iMEWJQ6m+L8O8lRUuSWXASUm/eX 65A2ILJlPwPootsOoh2gh8kJ+oMSlonYTnedJPSgT0QBHyRMqhIY0se/O+jMnhD8NSMN OFQkOBGAGPWpXDhcl3DdQfcmtFb8CNAzku07WRzNOFBjy7UyNH3ezwK7/7fyVBtv8q6e UpIg0yFqD5kwLckUL42RvdOEITS69hvSOr8gFrWBc6+KIxvTL5m62bRJBV1dJQ2J325r h18GXu1tThw1cvfAL6vUhdhHIwchIuN95MWS/B1gcNDC71Hwdg36B8fv5ljePlkg+bGm VV4w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=heIwSkRf; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id c2si1118961ejs.327.2020.10.02.10.55.42; Fri, 02 Oct 2020 10:56:05 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=heIwSkRf; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388270AbgJBRw1 (ORCPT + 99 others); Fri, 2 Oct 2020 13:52:27 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:23632 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726017AbgJBRw0 (ORCPT ); Fri, 2 Oct 2020 13:52:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601661145; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=UYhZcO1NLSMAx4sk89Nhzce3JSq4NgIfHV17KuBrZ9s=; b=heIwSkRfg1Z4nzVYlizNa6HHaG5ZGbtAf64Sb3sNoxiKDpf8FYeNTX4+mStEhAfN095yT9 LKffguVp+8OYgutDIYBhFGeOLTdqZRYm/uN7A89PSipJhOQ/62NPGpfAIn6YkYPdItRacH Ee5w3UgB6PoZ22mLdOwRrB6XCJ+Y+hs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-155-ZCci1aZmPEW9Wajk-4B_Fg-1; Fri, 02 Oct 2020 13:52:22 -0400 X-MC-Unique: ZCci1aZmPEW9Wajk-4B_Fg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2D007802B5E; Fri, 2 Oct 2020 17:52:21 +0000 (UTC) Received: from [10.36.113.228] (ovpn-113-228.ams2.redhat.com [10.36.113.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 107A37367D; Fri, 2 Oct 2020 17:52:19 +0000 (UTC) Subject: Re: [PATCH] mm: optionally disable brk() To: Topi Miettinen , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20201002171921.3053-1-toiwoton@gmail.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63W5Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAjwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat GmbH Message-ID: <653873ef-2a57-37e0-1ac3-fba763652b35@redhat.com> Date: Fri, 2 Oct 2020 19:52:19 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20201002171921.3053-1-toiwoton@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02.10.20 19:19, Topi Miettinen wrote: > The brk() system call allows to change data segment size (heap). This > is mainly used by glibc for memory allocation, but it can use mmap() > and that results in more randomized memory mappings since the heap is > always located at fixed offset to program while mmap()ed memory is > randomized. Want to take more Unix out of Linux? Honestly, why care about disabling? User space can happily use mmap() if it prefers. -- Thanks, David / dhildenb