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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7550CC43334 for ; Mon, 27 Jun 2022 16:07:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CA63B6B0071; Mon, 27 Jun 2022 12:07:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C2F486B0072; Mon, 27 Jun 2022 12:07:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AA90D8E0001; Mon, 27 Jun 2022 12:07:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 9618C6B0071 for ; Mon, 27 Jun 2022 12:07:39 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 6DB2360FE5 for ; Mon, 27 Jun 2022 16:07:39 +0000 (UTC) X-FDA: 79624496238.10.07C394D Received: from mail-pl1-f173.google.com (mail-pl1-f173.google.com [209.85.214.173]) by imf13.hostedemail.com (Postfix) with ESMTP id C0F1620040 for ; Mon, 27 Jun 2022 16:07:37 +0000 (UTC) Received: by mail-pl1-f173.google.com with SMTP id n10so8631021plp.0 for ; Mon, 27 Jun 2022 09:07:37 -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=l0pibN8bjG0PnvfGdr94sagjrAjKQlwTKx4ke7hg5TE=; b=KXpJaULYCMOBvM0KZ+Y0QmYKcs5GsOT3UDoT12OxOmZTuofXiRwwGm/WgJTM1heXoI t1dv3k342OQnZ9iooXjd608cniWLl0qlDw2/EFrZO3JITiMUniSnoS9vRpsVYcQj8vN/ I7nko6H+yxfXlWmj6BpVmIQCvWqpF55RTmiG3dExwV8krl6JWA8dxuz7o3cuKUtlCKLL AUH1GrHaKcLi0AxNkq1Q0RlPIztx9SDq4ccjZXK7Aa2jkpBZXbRVUSJ+/fIBfJxIB9bo wqHrvEDbll+Qw87/iH2rzRcMOLCQ34VpKyfcZXoB0fUgM3GYU80A2xB80LHN6E80KQa1 5riQ== 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=l0pibN8bjG0PnvfGdr94sagjrAjKQlwTKx4ke7hg5TE=; b=bRKbAT62fbU/41I3xcStkmQPvFHHbAsRzyxEsDTxXQeOgyR0Iez4eCedVWniHjmGyX KCnwubOxID5fhJStuuYHPVPCB66u0gvP3a22uwj5IN/OJ6GDkIFkCFgWHHMF4GyOEec0 elqiDOiOGOxfiLLKiIxlg7OXK57mwnJKb3bxMU5+uTzhiu9bjvZooCNtCjEc1NE3NPXn LgFrOr745Gmq6lpwkos3iSHRwHZfbltgNWQMjH1nACKltsL8MTAIRt/6xtKycSfjfsb8 J0SV7YEmiueBIfYxiSGYMeVmFTbGM3A1oKZIRxWcFlR2oYr452GiEqVZk8uJ+YefNNG3 uRYA== X-Gm-Message-State: AJIora92nt0YMsbSp9PISRvVrbFgu9wmIlgefXiFuCNXy6hAWJbXPoqe g6R5Cb+3HiEe6HGEOZCOPhYmTQ== X-Google-Smtp-Source: AGRyM1uyfo5AfaNgmfF7G/qEE7dWnvzScXgctBWfKk3cum7fj6D7nx+TeglAS/qAbSPCsy6MAsmoPA== X-Received: by 2002:a17:902:9f97:b0:16a:9b9:fb63 with SMTP id g23-20020a1709029f9700b0016a09b9fb63mr15547216plq.7.1656346056250; Mon, 27 Jun 2022 09:07:36 -0700 (PDT) Received: from google.com (123.65.230.35.bc.googleusercontent.com. [35.230.65.123]) by smtp.gmail.com with ESMTPSA id g17-20020aa78191000000b005254bd90f22sm7528584pfi.150.2022.06.27.09.07.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Jun 2022 09:07:35 -0700 (PDT) Date: Mon, 27 Jun 2022 16:07:32 +0000 From: Sean Christopherson To: Yosry Ahmed Cc: Tejun Heo , Johannes Weiner , Zefan Li , Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Andrew Morton , Michal Hocko , Roman Gushchin , Shakeel Butt , Oliver Upton , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v5 1/4] mm: add NR_SECONDARY_PAGETABLE to count secondary page table uses. Message-ID: References: <20220606222058.86688-1-yosryahmed@google.com> <20220606222058.86688-2-yosryahmed@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220606222058.86688-2-yosryahmed@google.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656346059; a=rsa-sha256; cv=none; b=ZQrxExvQAfsVgDtH48+ZTfF+W9SmW1Bvv6X0SLiEylyWv0x6aaug5ENu0JmnSTejbSJYWp XbVCIrBHuVQ1pZL62/99VCcIjjweHAA1/Nj1WQ55Re0o2U3vg1dl/U2NWlFY8RDkAGo8ab l9IkACGJOOLS608QZsOKe2CaQ5fctN4= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=KXpJaULY; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf13.hostedemail.com: domain of seanjc@google.com designates 209.85.214.173 as permitted sender) smtp.mailfrom=seanjc@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656346059; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=l0pibN8bjG0PnvfGdr94sagjrAjKQlwTKx4ke7hg5TE=; b=T+pSmqUb7WCNkJ/R54ehEnqtExAGsUaqipfSK0RzqOEIlIKqAHkIG33lzdkhIpWXCPSc8U xmPTsJ4n50Jgf2Elf4o4Gn/1wPM9Oa+bXDLIQJW8I+fMJy3kotV4DZfmF6WV/LRbiy0hgN tnXzxqT4hbMP15zJGprpjSxPjbTE58s= X-Stat-Signature: gbw7cr5kijhgm8kh64d8u337bnoxtqo3 X-Rspamd-Queue-Id: C0F1620040 Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=KXpJaULY; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf13.hostedemail.com: domain of seanjc@google.com designates 209.85.214.173 as permitted sender) smtp.mailfrom=seanjc@google.com X-Rspamd-Server: rspam10 X-Rspam-User: X-HE-Tag: 1656346057-881850 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jun 06, 2022, Yosry Ahmed wrote: > Add NR_SECONDARY_PAGETABLE stat to count secondary page table uses, e.g. > KVM mmu. This provides more insights on the kernel memory used > by a workload. Please provide more justification for NR_SECONDARY_PAGETABLE in the changelog. Specially, answer the questions that were asked in the previous version: 1. Why not piggyback NR_PAGETABLE? 2. Why a "generic" NR_SECONDARY_PAGETABLE instead of NR_VIRT_PAGETABLE? It doesn't have to be super long, but provide enough info so that reviewers and future readers don't need to go spelunking to understand the motivation for the new counter type. And it's probably worth an explicit Link to Marc's question that prompted the long discussion in the previous version, that way if someone does want the gory details they have a link readily available. Link: https://lore.kernel.org/all/87ilqoi77b.wl-maz@kernel.org