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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,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 ADB23C5519F for ; Mon, 30 Nov 2020 09:34:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 200322076E for ; Mon, 30 Nov 2020 09:34:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="DZmGHuBX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 200322076E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 88BC48D0002; Mon, 30 Nov 2020 04:34:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 83C548D0001; Mon, 30 Nov 2020 04:34:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 779338D0002; Mon, 30 Nov 2020 04:34:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0252.hostedemail.com [216.40.44.252]) by kanga.kvack.org (Postfix) with ESMTP id 622228D0001 for ; Mon, 30 Nov 2020 04:34:22 -0500 (EST) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 25F0C181AC9CB for ; Mon, 30 Nov 2020 09:34:22 +0000 (UTC) X-FDA: 77540573964.06.glue51_1a0fd11273a0 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin06.hostedemail.com (Postfix) with ESMTP id D7A0C10042B7A for ; Mon, 30 Nov 2020 09:34:21 +0000 (UTC) X-HE-Tag: glue51_1a0fd11273a0 X-Filterd-Recvd-Size: 3147 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by imf12.hostedemail.com (Postfix) with ESMTP for ; Mon, 30 Nov 2020 09:34:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=0rWZ/IKLgX5YBtYlsGOEnzcxhpN2D379f2O4Lio8snw=; b=DZmGHuBX23XyOb0cYXxLwKvpB+ 1QFJSgOTkI0TdQcuEDlwzcyxfvK3NW4jFlga+VMD1+hut7ZfTUVDPiUZg3xzF3qLlP+Ac1USFi6qp 4YPToAcqP+rNdlu7fqFgH0OGt0wmYCFT/6L1/DE07qbTOPFDXO4mKDdJhGVoRLRDUPLytj7/QB3QO 7btaCKCgshCA358zEjjiqbMdS8WOI/Oz2FA5XL/ZvrcoogYQU/ql+fcUXzEV2kuq7/40oBjjGMzwG PUnV/3WJfZ+yQycDAIuAN1vCwkquC+gl0cJ06EY6rBnJh+aLw1wUU17oDBEXk4K5uqm6mAfKXQMv4 eCafddhg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kjfZa-0001G5-CH; Mon, 30 Nov 2020 09:34:18 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 278DA3003E1; Mon, 30 Nov 2020 10:34:17 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 12B1720107BE2; Mon, 30 Nov 2020 10:34:17 +0100 (CET) Date: Mon, 30 Nov 2020 10:34:17 +0100 From: Peter Zijlstra To: Andy Lutomirski Cc: Nicholas Piggin , LKML , X86 ML , Mathieu Desnoyers , Arnd Bergmann , linux-arch , linuxppc-dev , Linux-MM , Anton Blanchard Subject: Re: [PATCH 6/8] lazy tlb: shoot lazies, a non-refcounting lazy tlb option Message-ID: <20201130093417.GI3092@hirez.programming.kicks-ass.net> References: <20201128160141.1003903-1-npiggin@gmail.com> <20201128160141.1003903-7-npiggin@gmail.com> <20201130093000.GM2414@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201130093000.GM2414@hirez.programming.kicks-ass.net> 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 Mon, Nov 30, 2020 at 10:30:00AM +0100, Peter Zijlstra wrote: > On Sat, Nov 28, 2020 at 07:54:57PM -0800, Andy Lutomirski wrote: > > This means that mm_cpumask operations won't need to be full barriers > > forever, and we might not want to take the implied full barriers in > > set_bit() and clear_bit() for granted. > > There is no implied full barrier for those ops. Neither ARM nor Power implies any ordering on those ops. But Power has some of the worst atomic performance in the world despite of that. IIRC they don't do their LL/SC in L1.