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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 921F3ECE588 for ; Tue, 15 Oct 2019 14:05:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F60021925 for ; Tue, 15 Oct 2019 14:05:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571148312; bh=iNdFITxGoV/+QqRd9iQcdX3LKbCrRpdY6xzLl71y/EI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=zVXfJwt036Fd2QbaSLXHYMIF9A7N3Scd/XhOTfjbamWl5nsVQ4h50L9I9EpLCpy/O 9CH7rWqfyAeoLtf9pnm2HYfipucjeHFwXDXl+0t6NdCjAOAH1V5wpxqhky4TNXnWE1 jLmI4xjjI8tPqnishuJAKYfDaFRGBJLOj04OWBVk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732431AbfJOOFL (ORCPT ); Tue, 15 Oct 2019 10:05:11 -0400 Received: from mx2.suse.de ([195.135.220.15]:38310 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732292AbfJOOFL (ORCPT ); Tue, 15 Oct 2019 10:05:11 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 88132AFBB; Tue, 15 Oct 2019 14:05:09 +0000 (UTC) Date: Tue, 15 Oct 2019 16:05:08 +0200 From: Michal Hocko To: "Guilherme G. Piccoli" Cc: Guilherme Piccoli , Qian Cai , linux-mm@kvack.org, mike.kravetz@oracle.com, linux-kernel@vger.kernel.org, Jay Vosburgh , "Guilherme G. Piccoli" Subject: Re: [PATCH] hugetlb: Add nohugepages parameter to prevent hugepages creation Message-ID: <20191015140508.GJ317@dhcp22.suse.cz> References: <4641B95A-6DD8-4E8A-AD53-06E7B72D956C@lca.pw> <20191015121803.GB24932@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 15-10-19 10:58:36, Guilherme G. Piccoli wrote: > On 10/15/19 9:18 AM, Michal Hocko wrote: > > I do agree with Qian Cai here. Kdump kernel requires a very tailored > > environment considering it is running in a very restricted > > configuration. The hugetlb pre-allocation sounds like a tooling problem > > and should be fixed at that layer. > > > > Hi Michal, thanks for your response. Can you suggest me a current way of > preventing hugepages for being created, using userspace? The goal for this > patch is exactly this, introduce such a way. Simply restrict the environment to not allocate any hugepages? Kdump already controls the kernel command line and it also starts only a very minimal subset of services. So who is allocating those hugepages? sysctls should be already excluded by default as Qian mentioned. -- Michal Hocko SUSE Labs