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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 938B8C2D0A3 for ; Thu, 29 Oct 2020 13:35:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2B26E2075E for ; Thu, 29 Oct 2020 13:35:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=bytedance-com.20150623.gappssmtp.com header.i=@bytedance-com.20150623.gappssmtp.com header.b="bHBQYcj8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727106AbgJ2NfG (ORCPT ); Thu, 29 Oct 2020 09:35:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725300AbgJ2NfF (ORCPT ); Thu, 29 Oct 2020 09:35:05 -0400 Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C9884C0613D3 for ; Thu, 29 Oct 2020 06:35:01 -0700 (PDT) Received: by mail-wr1-x443.google.com with SMTP id w1so2808819wrm.4 for ; Thu, 29 Oct 2020 06:35:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=KpTzlVayUqmIgARPOMPHIPf+pVQBXZ57u27MnCRyRl4=; b=bHBQYcj8neeWwxu6NrAHcOkwrOtEZGmaAjWKrh8jI1JhyZORzyCnXt3On6YqLd0N6p tErqMaeHRpKVhnOsWX3ipgXBeAanJDaLg2D8M4OQev81G0DQIHUklusbFlwpETgl05pA 9uzcGGNCaO4+1Zg9YIBIK8jKoXD+ErnUL7DN3jIGsEqoYlvUdmyR609Qw/hR5IczuWjV VOAARd7lzT6kY3GvtELMpY3LsYW8LByBImUhKXyPeXliSUfxfhqOAPaLA5/E3P/6e0Cw EAEc+4wV66ab4E6oPsOs9CQKokMSZ7Skmwwz6q3RzYKcpQ3sF5XwenicLyIEirLdcuLc LAJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=KpTzlVayUqmIgARPOMPHIPf+pVQBXZ57u27MnCRyRl4=; b=rpni5LZeJklKKYTBGcsJCMbi5D9/ZNN8qfSA8PsvQvOiNvn31U7oAd8wAJpD2s4SdJ XlMVEg+Y9Rn46BQSrSd4X3lQiXvrSF5Ib5UYtQ1vRY9vH8OmM1Y3GjpVPTALQ/ao/nt9 cdWELK0MJkoRCodrkw+w/f5F/nxYJPwY5XRDD6LuRVjjJbErXeXDrUD9zDNPH+/n5bs3 IgVyjdxghCtbCKqA+utv6UaIxz15MRd4tzMD+FNF+wJIAOxoewj85G89IkPT+jlfc40z e1TBkD25kjeyp4ycNwCWDWFx6kvb0t10/qaoOdT2z+0nHBbdecTBSEXDTpLFGRJSwKs2 K0kQ== X-Gm-Message-State: AOAM533L9hPI9TpC8Pf7U5Ox6j6AO5AbeRJeeUsd5bRKtSBwLgzF2tD+ q9rgBfUL+/gf7l8FTH2u6vnVDFNQL/A2Zf8CDOOxPw== X-Google-Smtp-Source: ABdhPJzoa2kj33P5RHtMoZgDs5yNcjZnapoviF7YdfZYL3bAMykZSBtyBQnjKWARVTGdeTQXxtRcORTM2XC5tC0dDY8= X-Received: by 2002:a5d:69d1:: with SMTP id s17mr5830591wrw.398.1603978500435; Thu, 29 Oct 2020 06:35:00 -0700 (PDT) MIME-Version: 1.0 References: <20201026145114.59424-1-songmuchun@bytedance.com> <20201026145114.59424-4-songmuchun@bytedance.com> <20201029102913.GA31881@linux> In-Reply-To: <20201029102913.GA31881@linux> From: Muchun Song Date: Thu, 29 Oct 2020 21:34:22 +0800 Message-ID: Subject: Re: [External] Re: [PATCH v2 03/19] mm/hugetlb: Introduce a new config HUGETLB_PAGE_FREE_VMEMMAP To: Oscar Salvador Cc: Jonathan Corbet , Mike Kravetz , Thomas Gleixner , mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, Peter Zijlstra , viro@zeniv.linux.org.uk, Andrew Morton , paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, Randy Dunlap , oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, Mina Almasry , David Rientjes , Matthew Wilcox , Xiongchun duan , linux-doc@vger.kernel.org, LKML , Linux Memory Management List , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Archived-At: List-Archive: List-Post: On Thu, Oct 29, 2020 at 6:29 PM Oscar Salvador wrote: > > On Mon, Oct 26, 2020 at 10:50:58PM +0800, Muchun Song wrote: > > The purpose of introducing HUGETLB_PAGE_FREE_VMEMMAP is to configure > > whether to enable the feature of freeing unused vmemmap associated > > with HugeTLB pages. Now only support x86. > > Why this needs to be a config thing? > If this space-memory-optimization does not come with a trade-off, > why does the user have to set this instead of coming by default? Now we only support x86_64. If we want to support other archs. We need some arch special code to support this feature. In the future, if this patch series is merged to mainline, I will implement this optimization for other archs. At that time we can remove the HUGETLB_PAGE_FREE_VMEMMAP. Thanks. > > > -- > Oscar Salvador > SUSE L3 -- Yours, Muchun