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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB99BC433F5 for ; Mon, 22 Nov 2021 04:22:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231676AbhKVEZR (ORCPT ); Sun, 21 Nov 2021 23:25:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230218AbhKVEZO (ORCPT ); Sun, 21 Nov 2021 23:25:14 -0500 Received: from mail-yb1-xb30.google.com (mail-yb1-xb30.google.com [IPv6:2607:f8b0:4864:20::b30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DE80BC061714 for ; Sun, 21 Nov 2021 20:22:08 -0800 (PST) Received: by mail-yb1-xb30.google.com with SMTP id v7so46671364ybq.0 for ; Sun, 21 Nov 2021 20:22:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mQsLjE4VGO0GATJ9B+7NKTiNyNHw6FkgFYmoa5dRxaE=; b=n2wxVyb1ktE/Q3z6Up43RPvke0doMGm7LsaT1A3inEXXo7bAW8Rv4agR9gFi4nxpYu QpRn+MB5CK+ksrmTA+vEFDRq+SBlaSnERuN8x4q3V87cSyalGIW1H8AcPIJ4ySa+il2C Upg+Ir/DKLdh+MGVdQoFBfT7pZJK8map2eTu3cqgYtA7UwZniDV+rcTlfYTduQ+X+Eja tmkpNU07wpIZbPVIoo+oG6Ca04ao5Wt+ny9hrx553Sh6afvyRqrtpfPs7M0bW39UqWzd 7ZwNKkjK4iru7FuLlVJ3F4JesEcJ7S+GspwGvM98J5bnSys3BhVg54PZWfIIyQIJlK1K TxBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mQsLjE4VGO0GATJ9B+7NKTiNyNHw6FkgFYmoa5dRxaE=; b=Pd+6XUlZmnkmXEzqPknRnaKXWsVGWJ9X8QSBPM4oxSldyQ/prXGcRFsBqxq5Bv4Jeb 1LEgB9uD6YHeOCb1t0UN7hR5lBxzbso+HOs61C2v7URPhaWwVzs6leZSygPYhgHkSIRD rEGMb+9OjSU21tp09Fr1VJJ0umOJ2PP6SMPX/ifsjs5zhELGEhEUPVVokgQIGcaklIyw kLW+Eqo12WaJJBd8S3J0omKdidQUr27F4Bs0ZdnEJCrtLzVbHpw8V3xQiRYPTfBEYMM2 buKzOmYBPcGDAHxsAx7S37G+SEyhZ8ZaNAw0axDWIF1dJJrhxRERtQrsXWsiyMUJFsrF w6rw== X-Gm-Message-State: AOAM533JcWYvCZK1uL7VIyzQdYJvAfHZLK4AQpwpTmw9yth4/1S6Edtp EMQ3SVG/7VCZYZHPPR29D+TtLighh/1DvSOvlWSmFw== X-Google-Smtp-Source: ABdhPJxkQANMOc1KWaxVyyp66k2Es4bDOOEupiGo2PTdTOZqGNwZC04+EYiUjduPrrRpVNzw4kkPbidwB/luXt/4NV0= X-Received: by 2002:a05:6902:1144:: with SMTP id p4mr3480817ybu.189.1637554928109; Sun, 21 Nov 2021 20:22:08 -0800 (PST) MIME-Version: 1.0 References: <20211101031651.75851-1-songmuchun@bytedance.com> <35c5217d-eb8f-6f70-544a-a3e8bd009a46@oracle.com> In-Reply-To: From: Muchun Song Date: Mon, 22 Nov 2021 12:21:32 +0800 Message-ID: Subject: Re: [PATCH v7 0/5] Free the 2nd vmemmap page associated with each HugeTLB page To: Mike Kravetz , Andrew Morton , Oscar Salvador , David Hildenbrand , Michal Hocko , Matthew Wilcox Cc: Jonathan Corbet , Xiongchun duan , fam.zheng@bytedance.com, Muchun Song , Qi Zheng , linux-doc@vger.kernel.org, LKML , Linux Memory Management List , "Song Bao Hua (Barry Song)" , Barry Song <21cnbao@gmail.com>, Chen Huang , "Bodeddula, Balasubramaniam" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 10, 2021 at 2:18 PM Muchun Song wrote: > > On Tue, Nov 9, 2021 at 3:33 AM Mike Kravetz wrote: > > > > On 11/8/21 12:16 AM, Muchun Song wrote: > > > On Mon, Nov 1, 2021 at 11:22 AM Muchun Song wrote: > > >> > > >> This series can minimize the overhead of struct page for 2MB HugeTLB pages > > >> significantly. It further reduces the overhead of struct page by 12.5% for > > >> a 2MB HugeTLB compared to the previous approach, which means 2GB per 1TB > > >> HugeTLB. It is a nice gain. Comments and reviews are welcome. Thanks. > > >> > > > > > > Hi, > > > > > > Ping guys. Does anyone have any comments or suggestions > > > on this series? > > > > > > Thanks. > > > > > > > I did look over the series earlier. I have no issue with the hugetlb and > > vmemmap modifications as they are enhancements to the existing > > optimizations. My primary concern is the (small) increased overhead > > for the helpers as outlined in your cover letter. Since these helpers > > are not limited to hugetlb and used throughout the kernel, I would > > really like to get comments from others with a better understanding of > > the potential impact. > > Thanks Mike. I'd like to hear others' comments about this as well. > From my point of view, maybe the (small) overhead is acceptable > since it only affects the head page, however Matthew Wilcox's folio > series could reduce this situation as well. > > Looking forward to others' comments. > Ping guys. Hi Andrew, Do you have any suggestions on this series to move it on? Thanks.