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=-12.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 1B55AC4332E for ; Wed, 17 Mar 2021 10:41:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC0FC64F5E for ; Wed, 17 Mar 2021 10:41:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230236AbhCQKks (ORCPT ); Wed, 17 Mar 2021 06:40:48 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:37606 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230051AbhCQKk2 (ORCPT ); Wed, 17 Mar 2021 06:40:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615977627; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+uA62LYXXYt34SbzMiUOo/GuFglM+koNWxYIoI0HaWE=; b=d5Z/nXPvdqcfX0LvzoLIcdsg7gNFgr5+v+NexEunJVjgcq5SLhQr7CO8bemWnFaG2WZGJa Dy1f8cJ26CPlkgFsWx6aQZrXhA9U3LeeM1IUQUZ66mvYvM3gOWoLBNPh5CFWlFLem/VoQO xo9fzCJyJJsxpnyeAYgrjmYtIClOaWo= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-600-35tD18ZuPAmb2vlaSY37Vw-1; Wed, 17 Mar 2021 06:40:26 -0400 X-MC-Unique: 35tD18ZuPAmb2vlaSY37Vw-1 Received: by mail-wr1-f71.google.com with SMTP id h21so18036691wrc.19 for ; Wed, 17 Mar 2021 03:40:25 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:subject:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=+uA62LYXXYt34SbzMiUOo/GuFglM+koNWxYIoI0HaWE=; b=p5h8736AbMZ030TIx6kcQdg2D2i8A8/L3eqzmg/92rIC5ceStEuf0ND/tieMPI+VW3 ghPIj/BIlcNK8omwml4VXNCuDLirBWP+qbHiYv8AlkuYPiFfmb/I+9HB93KvBNorH1CC LwEYTWPAcOAZ5L6FF5GT0JHJzUVqKtOUB9sWjo3DygPd+82umF8rq/tOOQWeT91wZYBR 2CrS4dDmLZ7HRh2+N4fXuQEWDo2xYfoyQTmSqKlVhNuYj18VTaIQ1a+50Spf7PbClm/q Zr/bVLPRLn0ijXCLDAV6qkPuM5FxcQGoQpq9jBZMVG8MDTJliT35cSrMUdxUULkAUSHo KCHw== X-Gm-Message-State: AOAM532c4LCTSbDRZ1OhhBhaheRgvAN9MlzK9lernfXHz6VaNXBEkKpm 6PiaiFe4xQogpGWRO1Z+J8jtGFDjuvVU6A27J+b8m0Gy7tuhyYx4IqjXehSZjE71nCXaf/Yd6Yh B2kEeQOpARnxOb7HztXJvhtla X-Received: by 2002:a5d:4904:: with SMTP id x4mr3643792wrq.69.1615977624798; Wed, 17 Mar 2021 03:40:24 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzBZF3gGd+0hYA9nqALSuEG9p1iV25XmceN6jt1DKaC69m024BQgq4l21LRQchOZyC/bGwd1A== X-Received: by 2002:a5d:4904:: with SMTP id x4mr3643776wrq.69.1615977624655; Wed, 17 Mar 2021 03:40:24 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id p16sm30048521wrt.54.2021.03.17.03.40.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Mar 2021 03:40:24 -0700 (PDT) To: Marc Zyngier , Wanpeng Li Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Ben Gardon , Shakeel Butt References: <1615959984-7122-1-git-send-email-wanpengli@tencent.com> <87mtv2i1s3.wl-maz@kernel.org> From: Paolo Bonzini Subject: Re: [PATCH] KVM: arm: memcg awareness Message-ID: Date: Wed, 17 Mar 2021 11:40:23 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <87mtv2i1s3.wl-maz@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/03/21 10:10, Marc Zyngier wrote: >> @@ -366,7 +366,7 @@ static int hyp_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, >> if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1)) >> return -EINVAL; >> >> - childp = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL); >> + childp = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL_ACCOUNT); > No, this is wrong. > > You cannot account the hypervisor page tables to the guest because we > don't ever unmap them, and that we can't distinguish two data > structures from two different VMs occupying the same page. If you never unmap them, there should at least be a shrinker to get rid of unused pages in the event of memory pressure. Paolo