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 944A1C433EF for ; Tue, 11 Jan 2022 02:25:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346587AbiAKCZC (ORCPT ); Mon, 10 Jan 2022 21:25:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346579AbiAKCZB (ORCPT ); Mon, 10 Jan 2022 21:25:01 -0500 Received: from mail-pl1-x62f.google.com (mail-pl1-x62f.google.com [IPv6:2607:f8b0:4864:20::62f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 735D5C06173F for ; Mon, 10 Jan 2022 18:25:01 -0800 (PST) Received: by mail-pl1-x62f.google.com with SMTP id w7so14928833plp.13 for ; Mon, 10 Jan 2022 18:25:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:subject:to:cc:references:in-reply-to:mime-version :message-id:content-transfer-encoding; bh=1nSGYhHp6awGMeT+4Vew5HuXwiw2XBFjZuDQom4mnVc=; b=kDFEy8ysPKyieBoDc7io/9sZ0SbCerAYh7rc9yDQ7cmqNe6xIbCsAUcheBXpdFEhx8 RlAYYVDZmDT7GUNEPmdw6Tz2mSbDrZSPnBiV0OcwIvXPJ9dI//jxFzobdq1aNoS241IK BLXjipehxEmQeSGCu5UcGArLzUcw7utkyaFdfzOobGSWPPtWvOUgQcx5vV76DFQdjyT2 TRXXGPlQY7FY1QfmbfyytMIQN15whWKUknzV1/oRNJa9+FpGgBpHG4qdezG8Rv3ifnlZ AxjydkZJxGY5pekNzpTurt6qZyem3NLL9LLmlR/yY0fBRWhXt3F3ym2Tjf5RPX08VQaE v9OA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:subject:to:cc:references:in-reply-to :mime-version:message-id:content-transfer-encoding; bh=1nSGYhHp6awGMeT+4Vew5HuXwiw2XBFjZuDQom4mnVc=; b=qCMmHccHealyciJyWZZk28eX2wviVu52cYyXvZw959uUsnMNJ2UxM7o+XZ7sxxi60m 7llplIYWhbHYxXMqe6KLYNo5ywHqYhXvpFcyI8DOkpzEWdxGOdWQQCOqC5giJOj2IEOw ZOU1uEChGLH2UaykAZ53jaTMVs3B858riI45H+F/H9bwvnvdAxqO/oqhmMe3WVv02D3C OMRXUtXT7WzB0PFnGduYYNvPj0ewlO248V6n8ryqq4wFg3jvBtZDqjZjCPwSfeKqjgIz Td3szfsxN/sSk5gJDkAqjVUE5PYcfyhTlvTt87HRJa98FCbcruNwAhyN9rwQGqdDedAt PSDw== X-Gm-Message-State: AOAM531CzMx0YYvO1M73x/6hBmX4B8NaDABg8j2jpbWrjZWO11K02mVF JXt9dW47QI4IxwmXcrqNTdk= X-Google-Smtp-Source: ABdhPJyRpojrUNiFPVD5I45rygGKiOTmajqSsgVpMyce095UmYc7P4v0rn9U8PDDl607h9zaAvQ4uQ== X-Received: by 2002:a17:902:6906:b0:149:7087:355c with SMTP id j6-20020a170902690600b001497087355cmr2189351plk.153.1641867901044; Mon, 10 Jan 2022 18:25:01 -0800 (PST) Received: from localhost (124-171-74-95.tpgi.com.au. [124.171.74.95]) by smtp.gmail.com with ESMTPSA id kb1sm318355pjb.56.2022.01.10.18.24.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Jan 2022 18:25:00 -0800 (PST) Date: Tue, 11 Jan 2022 12:24:55 +1000 From: Nicholas Piggin Subject: Re: [PATCH 16/23] sched: Use lightweight hazard pointers to grab lazy mms To: Linus Torvalds Cc: Andrew Morton , Anton Blanchard , Benjamin Herrenschmidt , Catalin Marinas , Dave Hansen , linux-arch , Linux-MM , Andy Lutomirski , Mathieu Desnoyers , Nadav Amit , Paul Mackerras , "Peter Zijlstra (Intel)" , Randy Dunlap , Rik van Riel , Will Deacon , the arch/x86 maintainers References: <7c9c388c388df8e88bb5d14828053ac0cb11cf69.1641659630.git.luto@kernel.org> <3586aa63-2dd2-4569-b9b9-f51080962ff2@www.fastmail.com> <430e3db1-693f-4d46-bebf-0a953fe6c2fc@www.fastmail.com> <484a7f37-ceed-44f6-8629-0e67a0860dc8@www.fastmail.com> <1641790309.2vqc26hwm3.astroid@bobo.none> <1641791321.kvkq0n8kbq.astroid@bobo.none> In-Reply-To: MIME-Version: 1.0 Message-Id: <1641867685.59h0j3zwhw.astroid@bobo.none> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Excerpts from Linus Torvalds's message of January 11, 2022 3:19 am: > On Sun, Jan 9, 2022 at 9:18 PM Nicholas Piggin wrote: >> >> This is the patch that goes on top of the series I posted. It's not >> very clean at the moment it was just a proof of concept. >=20 > Yeah, this looks like what x86 basically already effectively does. >=20 > x86 obviously doesn't have that TLBIE option, and already has that > "exit lazy mode" logic (although it does so differently, using > switch_mm_irqs_off(), and guards it with the 'info->freed_tables' > check). >=20 > But there are so many different possible ways to flush TLB's (the > whole "paravirt vs native") that it would still require some > double-checking that there isn't some case that does it differently.. Oh yeah x86 needs a little porting to be able to use this for sure, but there's no reason it couldn't do it. Thanks, Nick