From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-f200.google.com (mail-lj1-f200.google.com [209.85.208.200]) by kanga.kvack.org (Postfix) with ESMTP id B8BB28E00F9 for ; Sat, 5 Jan 2019 18:28:39 -0500 (EST) Received: by mail-lj1-f200.google.com with SMTP id t22-v6so10816122lji.14 for ; Sat, 05 Jan 2019 15:28:39 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id x66-v6sor35490602ljb.20.2019.01.05.15.28.38 for (Google Transport Security); Sat, 05 Jan 2019 15:28:38 -0800 (PST) Received: from mail-lj1-f172.google.com (mail-lj1-f172.google.com. [209.85.208.172]) by smtp.gmail.com with ESMTPSA id n8-v6sm14216334lji.90.2019.01.05.15.28.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 05 Jan 2019 15:28:36 -0800 (PST) Received: by mail-lj1-f172.google.com with SMTP id n18-v6so35264490lji.7 for ; Sat, 05 Jan 2019 15:28:35 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Linus Torvalds Date: Sat, 5 Jan 2019 15:28:19 -0800 Message-ID: Subject: Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Jann Horn Cc: Jiri Kosina , Andrew Morton , Greg KH , Peter Zijlstra , Michal Hocko , Linux-MM , kernel list , Linux API On Sat, Jan 5, 2019 at 3:16 PM Linus Torvalds wrote: > > It goes back to forever, it looks like. I can't find a reason. Our man-pages talk abouit the "without doing IO" part. That may be the result of our code, though, not the reason for it. The BSD man-page has other flags, but doesn't describe what "in core" really means: MINCORE_INCORE Page is in core (resident). MINCORE_REFERENCED Page has been referenced by us. MINCORE_MODIFIED Page has been modified by us. MINCORE_REFERENCED_OTHER Page has been referenced. MINCORE_MODIFIED_OTHER Page has been modified. MINCORE_SUPER Page is part of a large (``super'') page. but the fact that it has MINCORE_MODIFIED_OTHER does obviously imply that yes, historically it really did look up the pages elsewhere, not just in the page tables. Still, maybe we can get away with just making it be about our own page tables. That would be lovely. Linus 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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable 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 E8E29C43387 for ; Sat, 5 Jan 2019 23:28:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A40E6222BB for ; Sat, 5 Jan 2019 23:28:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Vy1s/+P5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A40E6222BB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 551C58E0134; Sat, 5 Jan 2019 18:28:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4D8E28E00F9; Sat, 5 Jan 2019 18:28:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 37A578E0134; Sat, 5 Jan 2019 18:28:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-lj1-f200.google.com (mail-lj1-f200.google.com [209.85.208.200]) by kanga.kvack.org (Postfix) with ESMTP id B8BB28E00F9 for ; Sat, 5 Jan 2019 18:28:39 -0500 (EST) Received: by mail-lj1-f200.google.com with SMTP id t22-v6so10816122lji.14 for ; Sat, 05 Jan 2019 15:28:39 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:mime-version:references :in-reply-to:from:date:message-id:subject:to:cc; bh=5UH4pfWyQs4/o8iN9usZb3uixTnpzedXbZLwZju+Xnw=; b=NMHkyy9dVThDTJz9uKq39fzvEuhKpJXtjeTHESZQ0xbiv5pOBbuHyGrJVcXpi21c5j p0ZurxQURxcj6a3VGfV1oWSYUAhGAaVwZ7LTqL0eCwjbn4SLtxxlzi2xrVciUxSxZCdF N1gbOj78PDenbg70Djtdb5XjdH/ylY6cLXBrar8/OIp63WMz68877yMG/MtfGuo43IQZ aON2QxsHNOb0gzRBdwijO/nFk75yWuIiw45hA1ZsWkDuOmI0nkDx5ljX3cRPwVmh5UdQ 90j1W4OVNlGYI8uyMGc7x+KsmfI1ecoqkcYRZZ7FKv2l21FVsuE6f2ndLb42/GEatBxh n5lw== X-Gm-Message-State: AJcUukcL6kDFY19rgO8LaEyr7pmnDUjqWK1g+rMDC/3jzkQwnIPZvu4F GiXhrIw/1sJBCKR6RdP1Qp8j/E7JcA4Q7GRBkh5U0OK62hdIIxve8f6K7EZJ7Hoz+/YJRxJRft3 iwvcsBSYjw7eNaGWL0LdK1lB8qUNvUtmmLBSKcQOj5uz5rST9DT23DIvz9jlv6ClADh6ljjJvzz m/13T4RVGCp+gMcdIzJEBgWN093UQPUayalNQdwIyn+diqq1uVLQecTNn/MYDSxmsfCz1tcvxRJ bGTTYSJkr1Ca1TFxcgGYrlzb+VR0Q445DEU8WddVflkxoekEThRUi0+mgecInwRQrC0I913SkgN kttSnKuCOWt3iU2bLKdS35l8tcH0WlAJc2ja0Y6fsKVwteaggCBPdhPjH2/gA3O7L8m1uHOhpz7 S X-Received: by 2002:a2e:9c52:: with SMTP id t18-v6mr26063190ljj.149.1546730919175; Sat, 05 Jan 2019 15:28:39 -0800 (PST) X-Received: by 2002:a2e:9c52:: with SMTP id t18-v6mr26063180ljj.149.1546730918339; Sat, 05 Jan 2019 15:28:38 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1546730918; cv=none; d=google.com; s=arc-20160816; b=qwyt/9SYabCGcn6h8I0yywVJUWAWOMjkzqbzF33ZDkILXsO3wYMQe+/Tk0FFrav8uq 7Db7Hu42lV1iboOvrv9okQrHEbMvkW3m+8xsAQ7udJ3ZblGwxX6Ltv97dj4Inp4pXvyz /DNSJ9+2U/AxTsSvTVbkKvG+NqT3yghk8iKmuPpNmhj2W5zF68jYfGDWR/cfDB23+ujc fvFGHtWCGHR89TerVSm75A0iVsKfkl/y5UDKHlPat+Fs0ISdVD+m09B9dM8vrZUQOaY6 38wQnvD9kGmq4jhi4Itlg4FkSISI+jHcXnB9zRluMNDtxf+plMDr1d889uo/3LC9rSB/ neyw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:dkim-signature; bh=5UH4pfWyQs4/o8iN9usZb3uixTnpzedXbZLwZju+Xnw=; b=wxaSCDidB2CXpxSVlzC3Ldyq41ziDQiotGa637vbBfT/IDsjNoYhYL6y+2/txcuBnv Jyu1uMEkrml4wavEn8rkiEDDKckEUIluoXKI5KibZmOC/yjHJmbDQTd0qt6nVd4FqqvM PWeNyrdokqnTl41Ixurw+eW347TW217l/c4blWBOandbQzrpMa2EIxzUiyqRgTVGXvmY zrnRKbdcLnvBHUBCsPvAqy6rx6G2t2v8f7sArgT6LPAx3CMHA97jhvyb1AVlt1EVKhG5 mbuGkoHqojB5r1Ay6nEX8cS90rVMBHrAJaI8kTgbSmQLOIowjVSWOmUBaW0F3oXpjqGc /27A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linux-foundation.org header.s=google header.b="Vy1s/+P5"; spf=pass (google.com: domain of torvalds@linuxfoundation.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. 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[209.85.208.172]) by smtp.gmail.com with ESMTPSA id n8-v6sm14216334lji.90.2019.01.05.15.28.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 05 Jan 2019 15:28:36 -0800 (PST) Received: by mail-lj1-f172.google.com with SMTP id n18-v6so35264490lji.7 for ; Sat, 05 Jan 2019 15:28:35 -0800 (PST) X-Received: by 2002:a2e:9983:: with SMTP id w3-v6mr15001293lji.133.1546730915544; Sat, 05 Jan 2019 15:28:35 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Linus Torvalds Date: Sat, 5 Jan 2019 15:28:19 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged To: Jann Horn Cc: Jiri Kosina , Andrew Morton , Greg KH , Peter Zijlstra , Michal Hocko , Linux-MM , kernel list , Linux API Content-Type: text/plain; charset="UTF-8" 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: Message-ID: <20190105232819.6OsdO__63Y7aCrngmR1KlOxwxH3DR0D1c-e_omgoK8o@z> On Sat, Jan 5, 2019 at 3:16 PM Linus Torvalds wrote: > > It goes back to forever, it looks like. I can't find a reason. Our man-pages talk abouit the "without doing IO" part. That may be the result of our code, though, not the reason for it. The BSD man-page has other flags, but doesn't describe what "in core" really means: MINCORE_INCORE Page is in core (resident). MINCORE_REFERENCED Page has been referenced by us. MINCORE_MODIFIED Page has been modified by us. MINCORE_REFERENCED_OTHER Page has been referenced. MINCORE_MODIFIED_OTHER Page has been modified. MINCORE_SUPER Page is part of a large (``super'') page. but the fact that it has MINCORE_MODIFIED_OTHER does obviously imply that yes, historically it really did look up the pages elsewhere, not just in the page tables. Still, maybe we can get away with just making it be about our own page tables. That would be lovely. Linus