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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 E2D42ECE58D for ; Fri, 11 Oct 2019 23:36:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B71882190F for ; Fri, 11 Oct 2019 23:36:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="aXDs1GdP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727661AbfJKXgA (ORCPT ); Fri, 11 Oct 2019 19:36:00 -0400 Received: from mail-qk1-f194.google.com ([209.85.222.194]:46084 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726354AbfJKXgA (ORCPT ); Fri, 11 Oct 2019 19:36:00 -0400 Received: by mail-qk1-f194.google.com with SMTP id 201so10420604qkd.13 for ; Fri, 11 Oct 2019 16:35:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=aRw8hJuPAozTmVQlfAga1PNrnmiO6p/5H/4R+qW5ALA=; b=aXDs1GdPzcKKKOormFuS//NALpRaYnAjkxNTHPHLD7VaOZIKk/W9CyrGLEK/DMwtQe 4CSKWUm5/ZnCR4p20bpX5RPlWNUqqt+7aYwRcQBHzWhAnytQ7wvawwGBx/77oItQmAn7 jaifqJs4zff2zMJyOMSzLNiZ4Zd33e9LPY2QcodFP03XCmAvFTSOU8uDowX12QM4AYbq cEyMJGhkg2MRKnHLcdNUbWTgUNn3q32BS3NNRuJbzpksO+RIhhgR534TjGKaiNEZGx9T 77iGve+xvPeZhmyoFJ+sPOTFHZ9QT8PVq/Gg/Z99FqBB6OQN77ZUT7SPPSREAaY9o0yp I8XQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:content-transfer-encoding:from:mime-version :subject:date:message-id:references:cc:in-reply-to:to; bh=aRw8hJuPAozTmVQlfAga1PNrnmiO6p/5H/4R+qW5ALA=; b=CdnUmERdULery6pCDfIvLbAKNFj2/pUB6MZFGkejPXR9zP6SvzKVy53uOhn82RGA6i ju23+D2q8xCYY/oP7jLliYfx5qMRZtO898dI/cUzwsKMeS2VhfH5Tqnn/PXqjq7pfXPx lRjZzfAzpUf44kIRIgXrbHt+CrkmdLhu5MfJq5tA+dSnBvuGniLaoS2K+dQUREJf3ccm DGdFvHcSsDaR6AIX1h84+zuCMRBARiIYDX9+ohaNiD/Czi2ZCT1LjEmwkAypoBa9M+Q6 2yJYsdLPtKomE1si3yBMJtkopsMV0/xuvEqLK+tP1Wo3Q71rOqCXdINOSZqGi+kL/H4v 1wug== X-Gm-Message-State: APjAAAXj4+kE6P7MDOf5JiU5R2lQQqQZMD+/kWK/bLubgRsADYla5TO0 E/SrbtQOrnG6lm3J1Q+qNGjENg== X-Google-Smtp-Source: APXvYqzSc2HFdsBlaqRV99E/dFMnMal4Vn5+RT/NZBdiuRn+HdHjluTCmENwQM2s/hsIK4S0YHx/UA== X-Received: by 2002:a37:412:: with SMTP id 18mr13073500qke.203.1570836959114; Fri, 11 Oct 2019 16:35:59 -0700 (PDT) Received: from [192.168.1.183] (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id q64sm5404232qkb.32.2019.10.11.16.35.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Oct 2019 16:35:58 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH] hugetlb: Add nohugepages parameter to prevent hugepages creation Date: Fri, 11 Oct 2019 19:35:57 -0400 Message-Id: <36C2B5DF-7F21-42C6-BA77-6D86EDCB6BB3@lca.pw> References: <20191011223955.1435-1-gpiccoli@canonical.com> Cc: linux-mm@kvack.org, mike.kravetz@oracle.com, linux-kernel@vger.kernel.org, jay.vosburgh@canonical.com, kernel@gpiccoli.net In-Reply-To: <20191011223955.1435-1-gpiccoli@canonical.com> To: "Guilherme G. Piccoli" X-Mailer: iPhone Mail (17A860) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Oct 11, 2019, at 6:40 PM, Guilherme G. Piccoli = wrote: >=20 > Kdump kernels won't benefit from hugepages - in fact it's quite opposite, > it may be the case hugepages on kdump kernel can lead to OOM if kernel > gets unable to allocate demanded pages due to the fact the preallocated > hugepages are consuming a lot of memory. >=20 > This patch proposes a new kernel parameter to prevent the creation of > HugeTLB hugepages - we currently don't have a way to do that. We can > even have kdump scripts removing the kernel command-line options to > set hugepages, but it's not straightforward to prevent sysctl/sysfs > configuration, given it happens in later boot or anytime when the > system is running. Typically, kdump kernel has its own initramfs, and don=E2=80=99t even need t= o mount a rootfs, so I can=E2=80=99t see how sysfs/sysctl is relevant here.=