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 EFA74FA3740 for ; Thu, 27 Oct 2022 17:30:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235951AbiJ0Ra3 (ORCPT ); Thu, 27 Oct 2022 13:30:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235840AbiJ0RaS (ORCPT ); Thu, 27 Oct 2022 13:30:18 -0400 Received: from mail-pf1-x433.google.com (mail-pf1-x433.google.com [IPv6:2607:f8b0:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AAF6F45F4C for ; Thu, 27 Oct 2022 10:30:14 -0700 (PDT) Received: by mail-pf1-x433.google.com with SMTP id i3so2249714pfc.11 for ; Thu, 27 Oct 2022 10:30:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=i90u/Uf2jYE0+hrCgqCAgN0GAbxmncytTIkPhq3S0qI=; b=EI6URPO1CuEaiVYhCgdKTi96gCaG7jguowcRqg1P4rQc2aXOhQRYoviwLuauhrW/rj IvfRngDCHxTCiVsKVGfU8yxjZxb0ta+useELLhjLfbgD1/HxloRXBMfNVokd2n6b7Sad nEk9LSxHfnHkooXNe2eHo083I7ypbpTaIBbgJ8BoiZhynYGFQMcjo7hFAjToVlD1Rz0D jeVspwwn5FV+spWcYEbo4AMNpX4vAj7y6zldSJY1GKiV+B48TcqBMTwvlTUXnusjvPTu ddhsnX1lhWxk/GmTwLYaWztZ25qT60u4w2PiGxETjmwnTcrao6EmIeN6WKqHhmTsFC2J dH4A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=i90u/Uf2jYE0+hrCgqCAgN0GAbxmncytTIkPhq3S0qI=; b=LYLZz3uproCCZpntVMtH2S51hewWz0Kk1tep8XTB5XoyfcY2P2TlTpHHol/S5kFeAS u5ixMhBJNXv0ggVYC8EkcUFF5XUcOqzySTCXzGHt2Nob28XgukGMyNyDOQsnYGRqghVn 776tAHYiBHoCPniHrdt5oYxZnDj3+GzjNNVaUU1S2Z/pYh8Qq5RVwzFzdi+NT1tQSUQz pwzkWbJb6Ot7SYOsCB9PFN7L5lNqICg02X0cKoqRfMGoJjGMseQoUChmAWTvK/KLEsQy Li4H/8L87gni8oTLzb7h3jwqrhjMHigmHKD7iJHWJux0kROIhdI4QRsEeHBaIFlkyvQM FIwg== X-Gm-Message-State: ACrzQf05ULwbys22yxLq+B/WZPKoTQS0lDEl8UmfXOdIEohK3XE02sAo DmGUXOmhzv8zODAZYAMygpI= X-Google-Smtp-Source: AMsMyM7jC2bcEuLwv2GZWzC1z7PmlNL6h5cLDonNo2ECQ5++cNinRUGeyy5ddU/iI8MIv/Wupb/9cQ== X-Received: by 2002:a65:4508:0:b0:43c:e3c6:d1c2 with SMTP id n8-20020a654508000000b0043ce3c6d1c2mr42555256pgq.582.1666891814045; Thu, 27 Oct 2022 10:30:14 -0700 (PDT) Received: from smtpclient.apple ([66.170.99.95]) by smtp.gmail.com with ESMTPSA id t2-20020aa79462000000b0056c063dd4cfsm1429687pfq.66.2022.10.27.10.30.12 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Oct 2022 10:30:13 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.1\)) Subject: Re: [PATCH 01/13] mm: Update ptep_get_lockless()s comment From: Nadav Amit In-Reply-To: Date: Thu, 27 Oct 2022 10:30:11 -0700 Cc: Jann Horn , John Hubbard , X86 ML , Matthew Wilcox , Linus Torvalds , Andrew Morton , kernel list , Linux-MM , Andrea Arcangeli , "Kirill A . Shutemov" , jroedel@suse.de, ubizjak@gmail.com Content-Transfer-Encoding: quoted-printable Message-Id: <1701B847-EE00-474A-ACF2-C4051884F8F1@gmail.com> References: <20221022111403.531902164@infradead.org> <20221022114424.515572025@infradead.org> <2c800ed1-d17a-def4-39e1-09281ee78d05@nvidia.com> To: Peter Zijlstra X-Mailer: Apple Mail (2.3696.120.41.1.1) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Oct 27, 2022, at 12:27 AM, Peter Zijlstra = wrote: >> One alternative may be using mm_tlb_flush_pending() when setting a = new PTE >> to check for pending flushes and flushing the TLB if that is the = case. This >> is somewhat similar to what ptep_clear_flush() does. Anyhow, I guess = this >> might induce some overheads. As noted before, it is possible to track >> pending TLB flushes in VMA/page-table granularity, with different = tradeoffs >> of overheads. >=20 > Right; I just don't believe in VMAs for this, they're *waaay* to big. Well, I did it for VMA in an RFC only because I was pushed. I thought = and do think that page-table granularity is the right one.=