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 69026C433EF for ; Sun, 9 Jan 2022 05:56:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9D4036B0072; Sun, 9 Jan 2022 00:56:50 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9841D6B0073; Sun, 9 Jan 2022 00:56:50 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 84C2A6B0074; Sun, 9 Jan 2022 00:56:50 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0001.hostedemail.com [216.40.44.1]) by kanga.kvack.org (Postfix) with ESMTP id 7588E6B0072 for ; Sun, 9 Jan 2022 00:56:50 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id ED99C92E11 for ; Sun, 9 Jan 2022 05:56:49 +0000 (UTC) X-FDA: 79009689738.03.C9F9294 Received: from mail-pj1-f49.google.com (mail-pj1-f49.google.com [209.85.216.49]) by imf20.hostedemail.com (Postfix) with ESMTP id 79F211C0003 for ; Sun, 9 Jan 2022 05:56:49 +0000 (UTC) Received: by mail-pj1-f49.google.com with SMTP id b1-20020a17090a990100b001b14bd47532so12697536pjp.0 for ; Sat, 08 Jan 2022 21:56:49 -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=BYgoseMaCQaqf6kS78DgqqK4BzLu4TTPo27v5EsTVGvZsTlhyalkMVLcxcCNNifu/y rzypAoybt81mXzZhoyvaxuudBA22xllwl3FeP3cqzWCIXmirIRG373AU3zunYpzFjZU7 kKjLsS5boRx+qXOxZTToyvU7NkIWwgFGcjPeFdzWg391l/9iPUSSe8cftTt+9sZjmK0D OUnR6f4MMKQqBZrbTCSS1klN9HSLSxY0QAlKBGkvC+tEYjj/ieBowXYy8BBDtUd7dhQQ 34B3g6zOQ/4tQepkvq6jD3AX2saMB/355iMIorWd0fG7IeVT5mmSTTD52/ixDkvJ/ZvJ l8+A== X-Gm-Message-State: AOAM530CrDKcLs2smzsrnTLiFUvsV3k1zqU0YAU4DYeneAsHk1XqN9ry u/gRcI5GuozjbI6E1yklTIw= 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) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b="Hkd9K/s1"; spf=pass (imf20.hostedemail.com: domain of nadav.amit@gmail.com designates 209.85.216.49 as permitted sender) smtp.mailfrom=nadav.amit@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 79F211C0003 X-Stat-Signature: mnep9zgzpeh78s35tekhhrpf3gfyeuop X-HE-Tag: 1641707809-382214 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 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?