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 2BABEC433FE for ; Sun, 9 Jan 2022 05:56:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235173AbiAIF4t (ORCPT ); Sun, 9 Jan 2022 00:56:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229960AbiAIF4t (ORCPT ); Sun, 9 Jan 2022 00:56:49 -0500 Received: from mail-pj1-x102e.google.com (mail-pj1-x102e.google.com [IPv6:2607:f8b0:4864:20::102e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0101AC06173F for ; Sat, 8 Jan 2022 21:56:49 -0800 (PST) Received: by mail-pj1-x102e.google.com with SMTP id ie23-20020a17090b401700b001b38a5318easo3573578pjb.2 for ; Sat, 08 Jan 2022 21:56:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=YQ3N/XCzp9QF6bsJmUFotftFxkyrPK0SSHmU+gmOo2U=; b=Hkd9K/s16ohx4c4W4u2XdH2i/MBtFnq1k0awDuIq6XKx/0znSo362sRVeItIe8SXQe 8SDGe5B2F/ll8pNhuvdknr34oh29HBSHl0LEt2X80tEVvOcaECmd4J7Iq+dnVq/mbcOO aY04WMDZhzcXbz2Aq8n0yRuvIGzjh+ozBiLK16ajxk7O2MY3bcrvZ09yf/Kcj6/G28g9 vr1t/emd8cFlN4Vaq17psR9TSSq6dqHwx8UmmyovcyU4pcKacwJy9Ee2cuVtv3XjFL3f iDTYuR8iFHbDiuKNIgGU3DOBo61eoNAl5Fh0+C68C+6wsWfjcP7+dk+r53jLXZfPE51H 2Ywg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=YQ3N/XCzp9QF6bsJmUFotftFxkyrPK0SSHmU+gmOo2U=; b=v+9MnBDbI6cvn2msehq0NcGNzXaLCPI1PNFqWDEFwzWzcgFi7fHP9YqFrc6k4puADR auViUlORYDPtnAckGxlrp7aB97sler+M2oEO1OZvCSnI/6HKuJ0dM6ppVO+vb3C/Lnxk IqMaHa1iGajMGIkUih7oIvLHkdWqKSA8+acCK8Bo4bgrzmi/JOWDgQm55LKtM9Ei/fXJ zafLueW/CQbMvwPOpmTd2vDlmFPkS2CMh4hjbhV+rSIT1cQTKlyzoUiGM1RZ9YU7kAgA 3nRWyjYIb0ANESMXqXcnXbIRGBPQm2oq5jN/JagDbqYJ0PQcqfT+Ul9/l+yA18CFtRkq Ekbg== X-Gm-Message-State: AOAM531LJfHGfo6RoI7cydqUqTnnWbcNQsqtgwnS1QLL+FHdreSGjORK mNR4WP+1Sw07yRM7GunuPpo= X-Google-Smtp-Source: ABdhPJxQqRGUvZt52Hw6VUiIcbS8BLGEZjDOT+nXfe7Irx0K1XSmEQvmJecm86R0hyikKzisXjw8Yg== X-Received: by 2002:a17:903:2352:b0:14a:b4a:4629 with SMTP id c18-20020a170903235200b0014a0b4a4629mr8330722plh.45.1641707808255; Sat, 08 Jan 2022 21:56:48 -0800 (PST) Received: from smtpclient.apple (c-24-6-216-183.hsd1.ca.comcast.net. [24.6.216.183]) by smtp.gmail.com with ESMTPSA id on2sm4885712pjb.19.2022.01.08.21.56.46 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 08 Jan 2022 21:56:47 -0800 (PST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.120.0.1.13\)) Subject: Re: [PATCH 16/23] sched: Use lightweight hazard pointers to grab lazy mms From: Nadav Amit In-Reply-To: <7c9c388c388df8e88bb5d14828053ac0cb11cf69.1641659630.git.luto@kernel.org> Date: Sat, 8 Jan 2022 21:56:45 -0800 Cc: Andrew Morton , Linux-MM , Nicholas Piggin , Anton Blanchard , Benjamin Herrenschmidt , Paul Mackerras , Randy Dunlap , linux-arch , X86 ML , Rik van Riel , Dave Hansen , Peter Zijlstra , Mathieu Desnoyers , Linus Torvalds Content-Transfer-Encoding: quoted-printable Message-Id: <739A3109-04DD-4BA5-A02B-52EE30E820AE@gmail.com> References: <7c9c388c388df8e88bb5d14828053ac0cb11cf69.1641659630.git.luto@kernel.org> To: Andy Lutomirski X-Mailer: Apple Mail (2.3654.120.0.1.13) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org > On Jan 8, 2022, at 8:44 AM, Andy Lutomirski wrote: >=20 > The purpose of mmgrab() and mmdrop() is to make "lazy tlb" mode safe. Just wondering: In a world of ASID/PCID - does the =E2=80=9Clazy TLB=E2=80= =9D really have a worthy advantage? Considering the fact that with PTI anyhow address spaces are switched all the time, can=E2=80=99t we just get rid of it?