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=-3.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 38297C43387 for ; Fri, 18 Jan 2019 14:23:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0A1D920883 for ; Fri, 18 Jan 2019 14:23:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547821389; bh=FsLASoKsUR2hEwLe55WKKaJrXYzkv434ZZv/qnewgxg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=dBB9139WwHoaSOaIppB8sswqxdtiOo0HFH/RCgDWY7Hcd7O7lg4fUoV5p7PncLTMV v7vKxhC8oanE8u1rIQGMLRsyS6k9/0sR3epuCGVgxW1hltkxAkbV0/SnufpQTo2xJ5 nLcMylSxnSBq/zJ8E9XXAqMZHwYcPl5Eb7CMlrbk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727518AbfAROXH (ORCPT ); Fri, 18 Jan 2019 09:23:07 -0500 Received: from mail-yb1-f194.google.com ([209.85.219.194]:38398 "EHLO mail-yb1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727123AbfAROXG (ORCPT ); Fri, 18 Jan 2019 09:23:06 -0500 Received: by mail-yb1-f194.google.com with SMTP id x9so4403647ybj.5; Fri, 18 Jan 2019 06:23:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=fShawxudI26SvDbmZ3eSrcYp4BsXCd4u6t/WObVnJOs=; b=urmcgzTKKAN9cFALqi3SnsfcMXx3nk3V0CsP42IYiK7AXq26Dn09OU7KjwO8BAZKCx PYn9mrnU3Tj3xvcoevrmntqsbDmJTPi3nT5YEDxpXyZfpYOIJDnhzKjoo9bgTrcW7cJY YtuXp9bSD+NR52lOOYvHvhsl2IZtSRRYict3jo5jMZrFLsvb/+mF5aB1vnl38AXDVLUM BVY/2GiVJX8hhg5Cp83XqWjBVzBQlslsLLidzCyWwyq80AVGidXYrRe0L8JLThHP5WF6 Lh7XOAd7Pb+zFlsKzcIwwvGD5EGX4V1IMeHlmj9uku2hmX521JMfxjn2jYbSWWXw1DPk T/gg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=fShawxudI26SvDbmZ3eSrcYp4BsXCd4u6t/WObVnJOs=; b=XX61RpivHLHV3Ee16BbcJfGqHP5x4ZtqAMh54x8bzKcORYVp4rfSNPsIezaa87H0GE u21pMJWYlY4E8J0pD1tXOXjGJfBSc/1YcmJ0X635KNNC+u8xkERsm4Ftt3/wf3hDkxMC oMDmuF0IBb2AzVOp3aSu1nw2MKzYIm2UZ8PgENS6VOyUN0XstJfd7EmkV2txeOMZdjRd 860F8vzi3aZsqxpVSZPC33fyC2u5xx0YhI2UJ97cPeyPOwks1vAwtk93rujZKA2yrhz7 InpzUPn33M92AvHKgCukOD0wcBKor1gY7cgWagBLXP0AqfyvR5653gTR8cT2IXrD9qQr DO9g== X-Gm-Message-State: AJcUukdXb20B5nLwm/ULDlLqAfpxQGBZ0mp2mfXcW3sLJTZCZc+SD4Vo CwbVH50SsdRFupWqoLrtcmCruJ3I X-Google-Smtp-Source: ALg8bN65S+HR/xKxfr1sSLU4LhKw/a9sDj6TQysynAPP+2ix5SkZ1nyia3Id8m424R/r9wCIraURFg== X-Received: by 2002:a25:c886:: with SMTP id y128mr6622821ybf.250.1547821385124; Fri, 18 Jan 2019 06:23:05 -0800 (PST) Received: from localhost ([2620:10d:c091:200::6:586f]) by smtp.gmail.com with ESMTPSA id b144sm2604765ywa.33.2019.01.18.06.23.03 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 Jan 2019 06:23:03 -0800 (PST) Date: Fri, 18 Jan 2019 06:23:02 -0800 From: Tejun Heo To: Linus Torvalds Cc: Jiri Kosina , Masatake YAMATO , Andrew Morton , Greg KH , Peter Zijlstra , Michal Hocko , linux-mm@kvack.org, Linux List Kernel Mailing , linux-api@vger.kernel.org Subject: Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged Message-ID: <20190118142302.GC50184@devbig004.ftw2.facebook.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Linus. On Sat, Jan 05, 2019 at 01:54:03PM -0800, Linus Torvalds wrote: > And the first hit is 'fincore', which probably nobody cares about > anyway, but it does > > fd = open (name, O_RDONLY) > .. > mmap(window, len, PROT_NONE, MAP_PRIVATE, .. So, folks here have been using fincore(1) for diagnostic purposes and are also looking to expand on it to investigate per-cgroup cache usages (mmap -> mincore -> /proc/self/pagemap -> /proc/kpagecgroup -> cgroup path). These are all root-only usages to find out what's going on with the whole page cache. We aren't attached to doing things this particular way but it'd suck if there's no way. Thanks. -- tejun