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 E9E09C433FE for ; Wed, 1 Dec 2021 20:17:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352920AbhLAUUi (ORCPT ); Wed, 1 Dec 2021 15:20:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352921AbhLAUUY (ORCPT ); Wed, 1 Dec 2021 15:20:24 -0500 Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FC10C061748 for ; Wed, 1 Dec 2021 12:17:02 -0800 (PST) Received: by mail-pl1-x62c.google.com with SMTP id b13so18602582plg.2 for ; Wed, 01 Dec 2021 12:17:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=oxe9/TSVu6V7Nxp9vuY7vKO8sJu+J+68IwlCkOcIOoM=; b=hrA6yCB+jCTivvnoNrJz+OU9DlB9MNQhMH/2SZpjtuf7mZUmOREuchOO33vSXiIWOi xdNQaL7wZLr8squyH2h3s6L5Brc5NDAxOE/314OP8K0DspINdhvN/Gu7HDLrZlUHiJL+ dQxcnNBdSprzSi7/ZzKjx7LKCZVWTArkPdlkmJ+VqnVo8oJkiKHfiwMOvifyZ/i8WyOX snaOBFOQtYDMPRJIvjdsFr58NzPwiaYhnynU26V01gtSd3WfKloTga51GG4/LltrUX8Z QQFgZCHVgCfOmhh082ZzSPKjcOE0+g5d6hIIm3W0MuGFResQ1A7ulRmKG0gugsuvOaIr X1JA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=oxe9/TSVu6V7Nxp9vuY7vKO8sJu+J+68IwlCkOcIOoM=; b=E7gXgDdM9ADdMmioF4t27q3WiYPaK9DQQSdPkP9ppP0SxK9jp7hJzTQsxMU56iASHi VVJXwjLm0uDNghH9zwtJuyshg9CLytrWC1DF43Je5n+D+7es4aVrDg3t7+cas+bUZwfN QZLPqya8+oDkqb2oZkRSSZrccgSXaj/EUJgPofb6m5kKxCxjQmsiIWkD2cnLUorNzkNw iDz5gu/7Vir/Nx7WfvXWHPhXkZo60XrjzOOcUDPMBV3pA1MF0xIn92s1MsDLoAsIC7I3 nNFkmIL8/y11OJrpQQG4I84Ikf/LkvKYp2QLv4y03ar2DoYlng0PsedjxCQDXQbi0DEg 1giQ== X-Gm-Message-State: AOAM5308DELHPm/GwwMPHaGpirBohGSJ3X9AVzVOyDOuYZTmKI//wkO5 ljz8hHUT2qjytxXQEeiwoHUI7w== X-Google-Smtp-Source: ABdhPJwvIs1G/smkDDu8bqp58NCas7vWbMshtA/JXJVWg6ZDcOHgxt0wtNaFAbtSQt1xr3e65AGCcA== X-Received: by 2002:a17:90a:c08a:: with SMTP id o10mr586638pjs.44.1638389821865; Wed, 01 Dec 2021 12:17:01 -0800 (PST) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id d17sm646427pfo.40.2021.12.01.12.17.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Dec 2021 12:17:01 -0800 (PST) Date: Wed, 1 Dec 2021 20:16:57 +0000 From: Sean Christopherson To: Ben Gardon Cc: David Matlack , Paolo Bonzini , kvm@vger.kernel.org, Joerg Roedel , Jim Mattson , Wanpeng Li , Vitaly Kuznetsov , Janis Schoetterl-Glausch , Junaid Shahid , Oliver Upton , Harish Barathvajasankar , Peter Xu , Peter Shier Subject: Re: [RFC PATCH 13/15] KVM: x86/mmu: Split large pages during CLEAR_DIRTY_LOG Message-ID: References: <20211119235759.1304274-1-dmatlack@google.com> <20211119235759.1304274-14-dmatlack@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Dec 01, 2021, Ben Gardon wrote: > On Wed, Dec 1, 2021 at 11:22 AM Sean Christopherson wrote: > > I would prefer we use hugepage when possible, mostly because that's the terminology > > used by the kernel. KVM is comically inconsistent, but if we make an effort to use > > hugepage when adding new code, hopefully someday we'll have enough inertia to commit > > fully to hugepage. > > In my mind "huge page" implies 2M and "large page" is generic to 2m > and 1g. (IDK if we settled on a name for 1G pages) What about 4m PSE pages? :-) I'm mostly joking, but it does raise the point that trying to provide unique names for each size is a bit of a fools errand, especially on non-x86 architectures that support a broader variety of hugepage sizes. IMO, the least ambiguous way to refer to hugepages is to say that everything that isn't a 4k page (or whatever PAGE_SIZE is on the architecture) is a hugepage, and then explicitly state the size of the page if it matters. > I've definitely been guilty of reinforcing this inconsistent > terminology. (Though it was consistent in my head, of course.) If we > want to pick one and use it everywhere, I'm happy to get onboard with > a standard terminology. I hear you on using "large page", I've had to undo a solid decade of "large page" terminology from my pre-Linux days. But for better or worse, the kernel uses hugepage, e.g. hugetlbfs supports 1gb and 2mb pages. I think we should follow the kernel, especially since we have aspirations of unifying more of KVM's MMU across multiple architectures.