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 X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 396EEC433FE for ; Fri, 11 Dec 2020 00:11:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D21A424694 for ; Fri, 11 Dec 2020 00:11:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D21A424694 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 522046B0036; Thu, 10 Dec 2020 19:11:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4D2206B005D; Thu, 10 Dec 2020 19:11:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3E8B46B0068; Thu, 10 Dec 2020 19:11:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 283B26B0036 for ; Thu, 10 Dec 2020 19:11:51 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id E6B03180AD837 for ; Fri, 11 Dec 2020 00:11:50 +0000 (UTC) X-FDA: 77579073180.23.pin82_3b141b1273fc Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id CBB9837604 for ; Fri, 11 Dec 2020 00:11:50 +0000 (UTC) X-HE-Tag: pin82_3b141b1273fc X-Filterd-Recvd-Size: 2930 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Fri, 11 Dec 2020 00:11:50 +0000 (UTC) X-Gm-Message-State: AOAM531Ll3H+HuV35Sfr+rs9oLaxkMs/3UHRRw3hfHYGIl+mHHqQR1y1 V/lB1Exf6IU8dFsJqH3i3rnwqfuQ5gvlXOVoMQh5CA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607645509; bh=Cofiyz62cvN7fzCefudCkKNVJKZ45g5WsucZa64FPpA=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=C+0jn6o9vwUqjjd6f6CIgI8ic4Dc1d+O9ysXMT3QZQbI4JG6cNTs1xXSKSM5DkCvV FhOTbsiz7Z1d6drfO1VoXxt9NP2zpaXtAh00zU8Jzp0Mx1PKhhruws1mNybQscSirZ TvDZcXfTovOEPMgyK5/MAkgkWU1UaGo7MMD1BPm2VaLPuGjIvVfJhqKwWdEX4rvEbg UOGReXpyRtUliPrTjgLUOJLCdu0KcjG5pvNOcUs+ZcY98DQ8bER9e2pFUPW246aLTC OLUtPW/EFWAV8JXDukqZMTlMP/DwB49qgTg9qhZ4ufDIJfxeMP1oQ9txHO71iE6w12 qk9es7bV3hILw== X-Google-Smtp-Source: ABdhPJxDDSK+EyEWrV85EAnSD1YFD7Ma/HEk0AvjGndG+w0b26Y9PplLtS1ujaNX2t/s+KYP+0f/cLisBWT1kfjpRfA= X-Received: by 2002:adf:e64b:: with SMTP id b11mr10727032wrn.257.1607645507570; Thu, 10 Dec 2020 16:11:47 -0800 (PST) MIME-Version: 1.0 References: <1607152918.fkgmomgfw9.astroid@bobo.none> <116A6B40-C77B-4B6A-897B-18342CD62CEC@amacapital.net> <1607209402.fogfsh8ov4.astroid@bobo.none> <1607224014.8xeujbleij.astroid@bobo.none> In-Reply-To: <1607224014.8xeujbleij.astroid@bobo.none> From: Andy Lutomirski Date: Thu, 10 Dec 2020 16:11:36 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 2/8] x86: use exit_lazy_tlb rather than membarrier_mm_sync_core_before_usermode To: Nicholas Piggin Cc: Andy Lutomirski , Anton Blanchard , Arnd Bergmann , linux-arch , LKML , Linux-MM , linuxppc-dev , Mathieu Desnoyers , Peter Zijlstra , X86 ML Content-Type: text/plain; charset="UTF-8" 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 Dec 5, 2020, at 7:59 PM, Nicholas Piggin wrote: > > I'm still going to persue shoot-lazies for the merge window. As you > see it's about a dozen lines and a if (IS_ENABLED(... in core code. > Your change is common code, but a significant complexity (which > affects all archs) so needs a lot more review and testing at this > point. I don't think it's ready for this merge window. I read the early patches again, and I think they make the membarrier code worse, not better. I'm not fundamentally opposed to the shoot-lazies concept, but it needs more thought and it needs a cleaner foundation.