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=-0.6 required=3.0 tests=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 F30AFC54FCC for ; Tue, 21 Apr 2020 17:16:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBE15206D5 for ; Tue, 21 Apr 2020 17:16:59 +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="JsuqJaG0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729508AbgDURQ7 (ORCPT ); Tue, 21 Apr 2020 13:16:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46364 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726878AbgDURQ6 (ORCPT ); Tue, 21 Apr 2020 13:16:58 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EDE17C061A41; Tue, 21 Apr 2020 10:16:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=25trWX6WEnBP45ZCKj9I9u577utZjAybZI5wPJusmTQ=; b=JsuqJaG0t9Ueemdh2TossAsFXC Enrc7icqmuLeubDIWEaAT8FC8ETFfjzIlJOEAILBdsTGMbDcu60kY/dRzNlHkaNQNapU/WhlLsI3W SXMGRUIjSNAmO/5V8lpbJLl/PP765eLZhsRsTy62aL+ultW7JRjuzfm1AvUK4S6QhqngrKZN+aWyy oIbCtOi5vkohLY+qd3CdwTjwSa85Fqb9xkFdAz1xq++dGUb3WLzczuYGzJGRg5cHuWoHRliDDuqwq Ls9bYiHbS7DZacH/jygXDL7msouWmqPaKftbzP0qznzzEsDberPVYswJU3L6+GgFpZPNtatL+MhJq OSsK/Fkg==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jQwVl-00077n-1R; Tue, 21 Apr 2020 17:16:41 +0000 Date: Tue, 21 Apr 2020 10:16:41 -0700 From: Christoph Hellwig To: Peter Zijlstra Cc: Christoph Hellwig , Zhenyu Ye , mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, aneesh.kumar@linux.ibm.com, akpm@linux-foundation.org, npiggin@gmail.com, arnd@arndb.de, rostedt@goodmis.org, maz@kernel.org, suzuki.poulose@arm.com, tglx@linutronix.de, yuzhao@google.com, Dave.Martin@arm.com, steven.price@arm.com, broonie@kernel.org, guohanjun@huawei.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, xiexiangyou@huawei.com, zhangshaokun@hisilicon.com, linux-mm@kvack.org, arm@kernel.org, prime.zeng@hisilicon.com, kuhn.chenqun@huawei.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v1 1/6] arm64: Detect the ARMv8.4 TTL feature Message-ID: <20200421171641.GA25391@infradead.org> References: <20200403090048.938-1-yezhenyu2@huawei.com> <20200403090048.938-2-yezhenyu2@huawei.com> <20200421165346.GA11171@infradead.org> <20200421171328.GW20730@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200421171328.GW20730@hirez.programming.kicks-ass.net> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 21, 2020 at 07:13:28PM +0200, Peter Zijlstra wrote: > On Tue, Apr 21, 2020 at 09:53:46AM -0700, Christoph Hellwig wrote: > > On Fri, Apr 03, 2020 at 05:00:43PM +0800, Zhenyu Ye wrote: > > > From: Marc Zyngier > > > > > > In order to reduce the cost of TLB invalidation, the ARMv8.4 TTL > > > feature allows TLBs to be issued with a level allowing for quicker > > > invalidation. > > > > What does "issued with a level" mean? > > What I understood it to be is page-size based on page-table hierarchy. > Just like we have on x86, 4k, 2m, 1g etc.. > > So where x86 INVLPG will tear down any sized page for the address given, > you can now day, kill me the PMD level translation for @addr. > > Power9 radix also has things like this. Maybe this needs to be spelled out a little more? The current commit log sounds like paper generated by a neural network.