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=-11.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 AC04EC433E2 for ; Wed, 16 Sep 2020 02:11:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68A952087D for ; Wed, 16 Sep 2020 02:11:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="jge5AAJn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726254AbgIPCLT (ORCPT ); Tue, 15 Sep 2020 22:11:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726028AbgIPCLR (ORCPT ); Tue, 15 Sep 2020 22:11:17 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79044C06174A; Tue, 15 Sep 2020 19:11:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description; bh=nTKIBWOP6+WpdGT2H6jGa3P9YtQ8grc6+Ik6AGR2Qb8=; b=jge5AAJnaS9TAKULysr8Xc2YMC s9CakwAKXd+snWykDY8VDpiXY3MlJAy8TAr2fbKuIIDozCIZfMVJqOvnfcAuJpbRvcz9U8/adLuKI xDxs/NUBIeNIbSQZmn691oWqIYHm6/TMRuA51NWsMVusavMrO8hTNcizmjKAxc9xup1sR/bPoO5v+ 73WQPIQ/mHAwn1I3Hj1bH5gkEJvqfyD74V2rhI81ujeqyLxdit5YaLGL942QCotj3mVsbZxg8qCwc h8RwIQ9ikhgFawVW3ozqFvoUEYMBGAowuzZOHcC9CNrwv8DlljmTE9GLrQgyYSJsHoBDj51RMWvl4 nosL32/g==; Received: from [2601:1c0:6280:3f0::19c2] by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIMuc-00021E-TN; Wed, 16 Sep 2020 02:11:11 +0000 Subject: Re: [RFC PATCH 20/24] mm/hugetlb: Add a kernel parameter hugetlb_free_vmemmap To: Muchun Song , corbet@lwn.net, mike.kravetz@oracle.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, almasrymina@google.com, rientjes@google.com Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org References: <20200915125947.26204-1-songmuchun@bytedance.com> <20200915125947.26204-21-songmuchun@bytedance.com> From: Randy Dunlap Message-ID: Date: Tue, 15 Sep 2020 19:10:59 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200915125947.26204-21-songmuchun@bytedance.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Please see comments below. On 9/15/20 5:59 AM, Muchun Song wrote: > Add a kernel parameter hugetlb_free_vmemmap to disable the feature of > freeing unused vmemmap pages associated with each hugetlb page on boot. > > Signed-off-by: Muchun Song > --- > .../admin-guide/kernel-parameters.txt | 9 ++++++++ > Documentation/admin-guide/mm/hugetlbpage.rst | 3 +++ > mm/hugetlb.c | 23 +++++++++++++++++++ > 3 files changed, 35 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 5debfe238027..69d18ef6f66b 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1551,6 +1551,15 @@ > Documentation/admin-guide/mm/hugetlbpage.rst. > Format: size[KMG] > > + hugetlb_free_vmemmap= > + [KNL] When CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is set, > + this disables freeing unused vmemmap pages associated this controls > + each HugeTLB page. with each HugeTLB page. > + Format: { on (default) | off } > + > + on: enable the feature > + off: dosable the feature disable > + > hung_task_panic= > [KNL] Should the hung task detector generate panics. > Format: 0 | 1 > diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst > index f7b1c7462991..7d6129ee97dd 100644 > --- a/Documentation/admin-guide/mm/hugetlbpage.rst > +++ b/Documentation/admin-guide/mm/hugetlbpage.rst > @@ -145,6 +145,9 @@ default_hugepagesz > > will all result in 256 2M huge pages being allocated. Valid default > huge page size is architecture dependent. insert blank line here. > +hugetlb_free_vmemmap > + When CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is set, this disables freeing > + unused vmemmap pages associated each HugeTLB page. > > When multiple huge page sizes are supported, ``/proc/sys/vm/nr_hugepages`` > indicates the current number of pre-allocated huge pages of the default size. -- ~Randy