From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Upton Subject: Re: [PATCH v3 4/6] KVM: arm64/mmu: count KVM page table pages in pagetable stats Date: Thu, 28 Apr 2022 17:45:47 +0000 Message-ID: References: <20220426053904.3684293-1-yosryahmed@google.com> <20220426053904.3684293-5-yosryahmed@google.com> Mime-Version: 1.0 Return-path: 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=rYkNgcXPFsN0AZS9Gdq00dTATV9XxHLGEv5CoQhxVgg=; b=hzMsoV3D0yJ0Unlop+rpTzklIYhRnWH7ICsyDlDVFdcLE9BIlkNP73Wm+4oXNVuiB8 plJ8GuyyvEt6ZXQbKxd1muNdZzq09naSLXrKhBTeETybRl01LEoPVDN68ktaYn9l0zsi yoyQHHe1wradnURDVY6+HNGMMkWazXFQRLoTut+ycpEUb54hblTXLdMjgsITAqGXMdx5 3Y8FH49L78ooub0KNRfiN5ke97caoBhhHNMCuuOQncS7BD/mI1wPI6p0qS0ilNo4Z01F oWlrVzL07peONZe79tOTcyd8YQZsNWlwpVd98T9TgcHmPXq0Kuzw5WruzgVtu+f1uIoR iH0Q== Content-Disposition: inline In-Reply-To: List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Yosry Ahmed Cc: Sean Christopherson , Huacai Chen , Aleksandar Markovic , Anup Patel , Atish Patra , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , James Morse , Catalin Marinas , Shameer Kolothum , Marc Zyngier On Tue, Apr 26, 2022 at 12:27:57PM -0700, Yosry Ahmed wrote: > > What page tables do we want to account? KVM on ARM manages several page > > tables. > > > > For regular KVM, the host kernel manages allocations for the hyp stage 1 > > tables in addition to the stage 2 tables used for a particular VM. The > > former is system overhead whereas the latter could be attributed to a > > guest VM. > > Honestly I would love to get your input on this. The main motivation > here is to give users insights on the kernel memory usage on their > system (or in a cgroup). We currently have NR_PAGETABLE stats for > normal kernel page tables (allocated using > __pte_alloc_one()/pte_free()), this shows up in /proc/meminfo, > /path/to/cgroup/memory.stat, and node stats. The idea is to add > NR_SECONDARY_PAGETABLE that should include the memory used for kvm > pagetables, which should be a separate category (no overlap). What > gets included or not depends on the semantics of KVM and what exactly > falls under the category of secondary pagetables from the user's pov. > > Currently it looks like s2 page table allocations get accounted to > kmem of memory control groups (GFP_KERNEL_ACCOUNT), while hyp page > table allocations do not (GFP_KERNEL). So we could either follow this > and only account s2 page table allocations in the stats, or make hyp > allocations use GFP_KERNEL_ACCOUNT as well and add them to the stats. > Let me know what you think. I think it is reasonable to just focus on stage 2 table allocations and ignore all else. As Marc pointed out it isn't workable in other contexts anyway (pKVM), and keeps the patch tidy too. GFP_KERNEL_ACCOUNT for hyp allocations wouldn't make sense, as it is done at init to build out the system page tables for EL2. -- Thanks, Oliver From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Upton Date: Thu, 28 Apr 2022 17:45:47 +0000 Subject: [PATCH v3 4/6] KVM: arm64/mmu: count KVM page table pages in pagetable stats In-Reply-To: References: <20220426053904.3684293-1-yosryahmed@google.com> <20220426053904.3684293-5-yosryahmed@google.com> Message-ID: List-Id: To: kvm-riscv@lists.infradead.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Tue, Apr 26, 2022 at 12:27:57PM -0700, Yosry Ahmed wrote: > > What page tables do we want to account? KVM on ARM manages several page > > tables. > > > > For regular KVM, the host kernel manages allocations for the hyp stage 1 > > tables in addition to the stage 2 tables used for a particular VM. The > > former is system overhead whereas the latter could be attributed to a > > guest VM. > > Honestly I would love to get your input on this. The main motivation > here is to give users insights on the kernel memory usage on their > system (or in a cgroup). We currently have NR_PAGETABLE stats for > normal kernel page tables (allocated using > __pte_alloc_one()/pte_free()), this shows up in /proc/meminfo, > /path/to/cgroup/memory.stat, and node stats. The idea is to add > NR_SECONDARY_PAGETABLE that should include the memory used for kvm > pagetables, which should be a separate category (no overlap). What > gets included or not depends on the semantics of KVM and what exactly > falls under the category of secondary pagetables from the user's pov. > > Currently it looks like s2 page table allocations get accounted to > kmem of memory control groups (GFP_KERNEL_ACCOUNT), while hyp page > table allocations do not (GFP_KERNEL). So we could either follow this > and only account s2 page table allocations in the stats, or make hyp > allocations use GFP_KERNEL_ACCOUNT as well and add them to the stats. > Let me know what you think. I think it is reasonable to just focus on stage 2 table allocations and ignore all else. As Marc pointed out it isn't workable in other contexts anyway (pKVM), and keeps the patch tidy too. GFP_KERNEL_ACCOUNT for hyp allocations wouldn't make sense, as it is done at init to build out the system page tables for EL2. -- Thanks, Oliver 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 mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0EF44C433F5 for ; Thu, 28 Apr 2022 17:45:59 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 7359549EBE; Thu, 28 Apr 2022 13:45:59 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@google.com Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id AAyIeSFjsT9n; Thu, 28 Apr 2022 13:45:55 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 660D24B10C; Thu, 28 Apr 2022 13:45:55 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id D95BA49F28 for ; Thu, 28 Apr 2022 13:45:54 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XA+GZAboTaFL for ; Thu, 28 Apr 2022 13:45:52 -0400 (EDT) Received: from mail-io1-f49.google.com (mail-io1-f49.google.com [209.85.166.49]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 7002949E1E for ; Thu, 28 Apr 2022 13:45:52 -0400 (EDT) Received: by mail-io1-f49.google.com with SMTP id 125so7261310iov.10 for ; Thu, 28 Apr 2022 10:45:52 -0700 (PDT) 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=rYkNgcXPFsN0AZS9Gdq00dTATV9XxHLGEv5CoQhxVgg=; b=hzMsoV3D0yJ0Unlop+rpTzklIYhRnWH7ICsyDlDVFdcLE9BIlkNP73Wm+4oXNVuiB8 plJ8GuyyvEt6ZXQbKxd1muNdZzq09naSLXrKhBTeETybRl01LEoPVDN68ktaYn9l0zsi yoyQHHe1wradnURDVY6+HNGMMkWazXFQRLoTut+ycpEUb54hblTXLdMjgsITAqGXMdx5 3Y8FH49L78ooub0KNRfiN5ke97caoBhhHNMCuuOQncS7BD/mI1wPI6p0qS0ilNo4Z01F oWlrVzL07peONZe79tOTcyd8YQZsNWlwpVd98T9TgcHmPXq0Kuzw5WruzgVtu+f1uIoR iH0Q== 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=rYkNgcXPFsN0AZS9Gdq00dTATV9XxHLGEv5CoQhxVgg=; b=NbsME7MI1xCtmjZsCFZ3Q2ziYyo0+zoyPpiJMpbA0+TqM702aZxnG8Ar00NC8bvQSe xjB5KLSQns/+QKCX+7Nsd1IitMmxkKDHuupOo7ONnnfwxSz75jbkyJRALzD+DriW7DBU yskoFdjfG/0/WJf0OumOdXbVr5S4t/pnqbmzn5mVvDohMFp9N95zwwihz+An0Y9+vF87 80xqD6PaMTunhXTEhiAasCSOobrz1iCxlIVxXjsDdZ/rV0WJrpk+soxfPLvs162feomV wnJDUFbNoC9Y0ZS1a5NvQt45Fsthm8WB1dNSmnqBR5dm9ubO7G9jrbUDzlbttdRJlMyj fmsA== X-Gm-Message-State: AOAM533sU75vR438qcqqtkIY4tgCbvER0jI6nTS9JU3AU0rMT5I6UVIE Z+c56TCoTnwknzO346XIPj43hQ== X-Google-Smtp-Source: ABdhPJx/sYY/i7dOFt3+PaiV4KhSUz6X+tqTVPbVDr2OqPDCjEE/yaOau4YnhKo+v4gz0/SI7nAHRg== X-Received: by 2002:a02:cc48:0:b0:32b:14:4186 with SMTP id i8-20020a02cc48000000b0032b00144186mr6761137jaq.189.1651167951414; Thu, 28 Apr 2022 10:45:51 -0700 (PDT) Received: from google.com (194.225.68.34.bc.googleusercontent.com. [34.68.225.194]) by smtp.gmail.com with ESMTPSA id f15-20020a056e020c6f00b002cbc9935527sm269640ilj.83.2022.04.28.10.45.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Apr 2022 10:45:50 -0700 (PDT) Date: Thu, 28 Apr 2022 17:45:47 +0000 From: Oliver Upton To: Yosry Ahmed Subject: Re: [PATCH v3 4/6] KVM: arm64/mmu: count KVM page table pages in pagetable stats Message-ID: References: <20220426053904.3684293-1-yosryahmed@google.com> <20220426053904.3684293-5-yosryahmed@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Cc: Wanpeng Li , kvm@vger.kernel.org, Catalin Marinas , Roman Gushchin , Michal Hocko , Linux-MM , kvmarm@lists.cs.columbia.edu, Marc Zyngier , Joerg Roedel , Huacai Chen , Aleksandar Markovic , Johannes Weiner , Shakeel Butt , Atish Patra , cgroups@vger.kernel.org, Vitaly Kuznetsov , linux-arm-kernel@lists.infradead.org, Jim Mattson , linux-mips@vger.kernel.org, Linux Kernel Mailing List , kvm-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, Paolo Bonzini , Andrew Morton X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Tue, Apr 26, 2022 at 12:27:57PM -0700, Yosry Ahmed wrote: > > What page tables do we want to account? KVM on ARM manages several page > > tables. > > > > For regular KVM, the host kernel manages allocations for the hyp stage 1 > > tables in addition to the stage 2 tables used for a particular VM. The > > former is system overhead whereas the latter could be attributed to a > > guest VM. > > Honestly I would love to get your input on this. The main motivation > here is to give users insights on the kernel memory usage on their > system (or in a cgroup). We currently have NR_PAGETABLE stats for > normal kernel page tables (allocated using > __pte_alloc_one()/pte_free()), this shows up in /proc/meminfo, > /path/to/cgroup/memory.stat, and node stats. The idea is to add > NR_SECONDARY_PAGETABLE that should include the memory used for kvm > pagetables, which should be a separate category (no overlap). What > gets included or not depends on the semantics of KVM and what exactly > falls under the category of secondary pagetables from the user's pov. > > Currently it looks like s2 page table allocations get accounted to > kmem of memory control groups (GFP_KERNEL_ACCOUNT), while hyp page > table allocations do not (GFP_KERNEL). So we could either follow this > and only account s2 page table allocations in the stats, or make hyp > allocations use GFP_KERNEL_ACCOUNT as well and add them to the stats. > Let me know what you think. I think it is reasonable to just focus on stage 2 table allocations and ignore all else. As Marc pointed out it isn't workable in other contexts anyway (pKVM), and keeps the patch tidy too. GFP_KERNEL_ACCOUNT for hyp allocations wouldn't make sense, as it is done at init to build out the system page tables for EL2. -- Thanks, Oliver _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm 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 7A74CC433EF for ; Thu, 28 Apr 2022 17:45:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350601AbiD1RtJ (ORCPT ); Thu, 28 Apr 2022 13:49:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350588AbiD1RtI (ORCPT ); Thu, 28 Apr 2022 13:49:08 -0400 Received: from mail-io1-xd2b.google.com (mail-io1-xd2b.google.com [IPv6:2607:f8b0:4864:20::d2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8044485672 for ; Thu, 28 Apr 2022 10:45:52 -0700 (PDT) Received: by mail-io1-xd2b.google.com with SMTP id e3so3534245ios.6 for ; Thu, 28 Apr 2022 10:45:52 -0700 (PDT) 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=rYkNgcXPFsN0AZS9Gdq00dTATV9XxHLGEv5CoQhxVgg=; b=hzMsoV3D0yJ0Unlop+rpTzklIYhRnWH7ICsyDlDVFdcLE9BIlkNP73Wm+4oXNVuiB8 plJ8GuyyvEt6ZXQbKxd1muNdZzq09naSLXrKhBTeETybRl01LEoPVDN68ktaYn9l0zsi yoyQHHe1wradnURDVY6+HNGMMkWazXFQRLoTut+ycpEUb54hblTXLdMjgsITAqGXMdx5 3Y8FH49L78ooub0KNRfiN5ke97caoBhhHNMCuuOQncS7BD/mI1wPI6p0qS0ilNo4Z01F oWlrVzL07peONZe79tOTcyd8YQZsNWlwpVd98T9TgcHmPXq0Kuzw5WruzgVtu+f1uIoR iH0Q== 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=rYkNgcXPFsN0AZS9Gdq00dTATV9XxHLGEv5CoQhxVgg=; b=UQYmj2Ee/g8J/s+v7cfZ9Xc63HCMcsDPA5r7vBYiYT4KFnKtqQ2gLRB/khM64trovJ W6Z8rEC5vJPkYYUaT6GUUJqJMCtLbnMAE9uYQafzBKw1t+FfUKilGmHZIc22SN99N5XI qxIEXkjkPNoI12qQbDmcQQil1aR1C3veNww88kCUa8cBOyFJMNbW22AM3RPV/gkM7moj iSqLT+/JGl41j9kwFIS/KJ1h4r3OgpgiTuFJGTeMEVGHTUBkfUcInzZaFVLOQRsnUJqz pXBn20Ezv94QcoRTYhV2DtbI6Hw2sL2qJERP29O1eGAd/GUgV51qjRZcxb7nVpCUOHI8 vTOQ== X-Gm-Message-State: AOAM530G8LRTiytbGiZucMOL+f11HUEWxUKTppDOqmoGyRQyYk49YgYW VtsyfFSIHI5UOEE1+UcJG3sOoA== X-Google-Smtp-Source: ABdhPJx/sYY/i7dOFt3+PaiV4KhSUz6X+tqTVPbVDr2OqPDCjEE/yaOau4YnhKo+v4gz0/SI7nAHRg== X-Received: by 2002:a02:cc48:0:b0:32b:14:4186 with SMTP id i8-20020a02cc48000000b0032b00144186mr6761137jaq.189.1651167951414; Thu, 28 Apr 2022 10:45:51 -0700 (PDT) Received: from google.com (194.225.68.34.bc.googleusercontent.com. [34.68.225.194]) by smtp.gmail.com with ESMTPSA id f15-20020a056e020c6f00b002cbc9935527sm269640ilj.83.2022.04.28.10.45.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Apr 2022 10:45:50 -0700 (PDT) Date: Thu, 28 Apr 2022 17:45:47 +0000 From: Oliver Upton To: Yosry Ahmed Cc: Sean Christopherson , Huacai Chen , Aleksandar Markovic , Anup Patel , Atish Patra , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , James Morse , Catalin Marinas , Shameer Kolothum , Marc Zyngier , Alexandru Elisei , Suzuki K Poulose , linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, Linux Kernel Mailing List , linux-fsdevel@vger.kernel.org, Linux-MM , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Subject: Re: [PATCH v3 4/6] KVM: arm64/mmu: count KVM page table pages in pagetable stats Message-ID: References: <20220426053904.3684293-1-yosryahmed@google.com> <20220426053904.3684293-5-yosryahmed@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: linux-mips@vger.kernel.org On Tue, Apr 26, 2022 at 12:27:57PM -0700, Yosry Ahmed wrote: > > What page tables do we want to account? KVM on ARM manages several page > > tables. > > > > For regular KVM, the host kernel manages allocations for the hyp stage 1 > > tables in addition to the stage 2 tables used for a particular VM. The > > former is system overhead whereas the latter could be attributed to a > > guest VM. > > Honestly I would love to get your input on this. The main motivation > here is to give users insights on the kernel memory usage on their > system (or in a cgroup). We currently have NR_PAGETABLE stats for > normal kernel page tables (allocated using > __pte_alloc_one()/pte_free()), this shows up in /proc/meminfo, > /path/to/cgroup/memory.stat, and node stats. The idea is to add > NR_SECONDARY_PAGETABLE that should include the memory used for kvm > pagetables, which should be a separate category (no overlap). What > gets included or not depends on the semantics of KVM and what exactly > falls under the category of secondary pagetables from the user's pov. > > Currently it looks like s2 page table allocations get accounted to > kmem of memory control groups (GFP_KERNEL_ACCOUNT), while hyp page > table allocations do not (GFP_KERNEL). So we could either follow this > and only account s2 page table allocations in the stats, or make hyp > allocations use GFP_KERNEL_ACCOUNT as well and add them to the stats. > Let me know what you think. I think it is reasonable to just focus on stage 2 table allocations and ignore all else. As Marc pointed out it isn't workable in other contexts anyway (pKVM), and keeps the patch tidy too. GFP_KERNEL_ACCOUNT for hyp allocations wouldn't make sense, as it is done at init to build out the system page tables for EL2. -- Thanks, Oliver 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C87C4C433F5 for ; Thu, 28 Apr 2022 17:47:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=DwBvpYhGOoB8dpOd/fNrW7u9xiq41lt0iALzEUycf4w=; b=ojaPk/1xk+TztB UXe5Lw5DaFxhIL5wxHU2X2wCxxLBQ0Ofa5rrQMJwiSIt526P88Pj49HwHjB3+kndyOLrXjqXldozq D0l2GxfyQiTnk8tsl8HSukPzXgdSGsjbWN4yg0MaPWum0WT1uEOwEHIoQH/RSVmcHJKaFWs85Gxha p+bBb7cNtFZ79g3XIgbmRlWbp3BTvlT4rdWlqsFiPqW/bIa4VexixjZU2cZgH++VZmgpn00UUGjei kIJZeFdnX4TJLsSppCtxDsdKWs4TwiYq73TVuUBI3hLHfa4+AHPJ2XIyQ4Fm2PY2lCuxaVKgPv8DE CapPSN3dichvLeeszjVA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nk8DH-0084f1-3D; Thu, 28 Apr 2022 17:45:59 +0000 Received: from mail-io1-xd34.google.com ([2607:f8b0:4864:20::d34]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nk8DE-0084dZ-6C for linux-arm-kernel@lists.infradead.org; Thu, 28 Apr 2022 17:45:57 +0000 Received: by mail-io1-xd34.google.com with SMTP id h8so7242879iov.12 for ; Thu, 28 Apr 2022 10:45:52 -0700 (PDT) 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=rYkNgcXPFsN0AZS9Gdq00dTATV9XxHLGEv5CoQhxVgg=; b=hzMsoV3D0yJ0Unlop+rpTzklIYhRnWH7ICsyDlDVFdcLE9BIlkNP73Wm+4oXNVuiB8 plJ8GuyyvEt6ZXQbKxd1muNdZzq09naSLXrKhBTeETybRl01LEoPVDN68ktaYn9l0zsi yoyQHHe1wradnURDVY6+HNGMMkWazXFQRLoTut+ycpEUb54hblTXLdMjgsITAqGXMdx5 3Y8FH49L78ooub0KNRfiN5ke97caoBhhHNMCuuOQncS7BD/mI1wPI6p0qS0ilNo4Z01F oWlrVzL07peONZe79tOTcyd8YQZsNWlwpVd98T9TgcHmPXq0Kuzw5WruzgVtu+f1uIoR iH0Q== 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=rYkNgcXPFsN0AZS9Gdq00dTATV9XxHLGEv5CoQhxVgg=; b=aXvWK2LY0ual3K4kTnaiydgZ5tZ7VmOFBogyXax4HAQr1mX7mtIpb8sIXoKWc0/Uur HaqZnhWXW0XSNLDB+JcrJNHWBpj4g8gZO9hIHNgnolEWx4siXXsxU6vKUr+4OxPOVQgr gKwhW7G0LDejFer/7jX9R14eKEfWV28u8IFvkDdzt/81LUNM+oCIfV0yA9gwPy1d5RFO 2oKQafepffq7tKPqYkQMS2dXVYpLnINYiFWImmOhA227yowhVHt6Pq7jJBonKzOemvzB 51m33lmByKgaVe59nxX9SYCwYt6HqUzRSYvW6ahtN75gVlZAABm6W/lpVxfHV0kAZKIy zwVA== X-Gm-Message-State: AOAM532AHxu2gYkz8wpdG2V1uq9v3SJBsSBOiJWlhbzvcGdWq10w06Jc q0wZu9PamZFWdrW8SC61HWn9og== X-Google-Smtp-Source: ABdhPJx/sYY/i7dOFt3+PaiV4KhSUz6X+tqTVPbVDr2OqPDCjEE/yaOau4YnhKo+v4gz0/SI7nAHRg== X-Received: by 2002:a02:cc48:0:b0:32b:14:4186 with SMTP id i8-20020a02cc48000000b0032b00144186mr6761137jaq.189.1651167951414; Thu, 28 Apr 2022 10:45:51 -0700 (PDT) Received: from google.com (194.225.68.34.bc.googleusercontent.com. [34.68.225.194]) by smtp.gmail.com with ESMTPSA id f15-20020a056e020c6f00b002cbc9935527sm269640ilj.83.2022.04.28.10.45.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Apr 2022 10:45:50 -0700 (PDT) Date: Thu, 28 Apr 2022 17:45:47 +0000 From: Oliver Upton To: Yosry Ahmed Cc: Sean Christopherson , Huacai Chen , Aleksandar Markovic , Anup Patel , Atish Patra , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , James Morse , Catalin Marinas , Shameer Kolothum , Marc Zyngier , Alexandru Elisei , Suzuki K Poulose , linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, Linux Kernel Mailing List , linux-fsdevel@vger.kernel.org, Linux-MM , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Subject: Re: [PATCH v3 4/6] KVM: arm64/mmu: count KVM page table pages in pagetable stats Message-ID: References: <20220426053904.3684293-1-yosryahmed@google.com> <20220426053904.3684293-5-yosryahmed@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220428_104556_252785_A0208347 X-CRM114-Status: GOOD ( 23.89 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Apr 26, 2022 at 12:27:57PM -0700, Yosry Ahmed wrote: > > What page tables do we want to account? KVM on ARM manages several page > > tables. > > > > For regular KVM, the host kernel manages allocations for the hyp stage 1 > > tables in addition to the stage 2 tables used for a particular VM. The > > former is system overhead whereas the latter could be attributed to a > > guest VM. > > Honestly I would love to get your input on this. The main motivation > here is to give users insights on the kernel memory usage on their > system (or in a cgroup). We currently have NR_PAGETABLE stats for > normal kernel page tables (allocated using > __pte_alloc_one()/pte_free()), this shows up in /proc/meminfo, > /path/to/cgroup/memory.stat, and node stats. The idea is to add > NR_SECONDARY_PAGETABLE that should include the memory used for kvm > pagetables, which should be a separate category (no overlap). What > gets included or not depends on the semantics of KVM and what exactly > falls under the category of secondary pagetables from the user's pov. > > Currently it looks like s2 page table allocations get accounted to > kmem of memory control groups (GFP_KERNEL_ACCOUNT), while hyp page > table allocations do not (GFP_KERNEL). So we could either follow this > and only account s2 page table allocations in the stats, or make hyp > allocations use GFP_KERNEL_ACCOUNT as well and add them to the stats. > Let me know what you think. I think it is reasonable to just focus on stage 2 table allocations and ignore all else. As Marc pointed out it isn't workable in other contexts anyway (pKVM), and keeps the patch tidy too. GFP_KERNEL_ACCOUNT for hyp allocations wouldn't make sense, as it is done at init to build out the system page tables for EL2. -- Thanks, Oliver _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel