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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 6FDF5C2D0DB for ; Fri, 31 Jan 2020 19:40:23 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D36BA20707 for ; Fri, 31 Jan 2020 19:40:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D36BA20707 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 488SHS0jPWzDqkW for ; Sat, 1 Feb 2020 06:40:20 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 488SFn3zv1zDqSw for ; Sat, 1 Feb 2020 06:38:53 +1100 (AEDT) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 00VJcZbS006329; Fri, 31 Jan 2020 13:38:35 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 00VJcXRI006321; Fri, 31 Jan 2020 13:38:33 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 31 Jan 2020 13:38:33 -0600 From: Segher Boessenkool To: Christophe Leroy Subject: Re: [PATCH] powerpc/32s: Don't flush all TLBs when flushing one page Message-ID: <20200131193833.GF22482@gate.crashing.org> References: <20200131155150.GD22482@gate.crashing.org> <27cef66b-df5b-0baa-abac-5532e58bd055@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <27cef66b-df5b-0baa-abac-5532e58bd055@c-s.fr> User-Agent: Mutt/1.4.2.3i X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Mackerras , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Jan 31, 2020 at 05:15:20PM +0100, Christophe Leroy wrote: > Le 31/01/2020 à 16:51, Segher Boessenkool a écrit : > >On Fri, Jan 31, 2020 at 03:37:34PM +0000, Christophe Leroy wrote: > >>When the range is a single page, do a page flush instead. > > > >>+ start &= PAGE_MASK; > >>+ end = (end - 1) | ~PAGE_MASK; > >> if (!Hash) { > >>- _tlbia(); > >>+ if (end - start == PAGE_SIZE) > >>+ _tlbie(start); > >>+ else > >>+ _tlbia(); > >> return; > >> } > > > >For just one page, you get end - start == 0 actually? > > Oops, good catch. > > Indeed you don't get PAGE_SIZE but (PAGE_SIZE - 1) for just one page. You have all low bits masked off in both start and end, so you get zero. You could make the condion read "if (start == end)? Maybe a nicer way to describe what you do is "if start and end are on the same memory page, flush that page." Segher 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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 75F57C2D0DB for ; Fri, 31 Jan 2020 19:39:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 47AA720707 for ; Fri, 31 Jan 2020 19:39:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726677AbgAaTjD (ORCPT ); Fri, 31 Jan 2020 14:39:03 -0500 Received: from gate.crashing.org ([63.228.1.57]:58945 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726001AbgAaTjD (ORCPT ); Fri, 31 Jan 2020 14:39:03 -0500 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 00VJcZbS006329; Fri, 31 Jan 2020 13:38:35 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 00VJcXRI006321; Fri, 31 Jan 2020 13:38:33 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 31 Jan 2020 13:38:33 -0600 From: Segher Boessenkool To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc/32s: Don't flush all TLBs when flushing one page Message-ID: <20200131193833.GF22482@gate.crashing.org> References: <20200131155150.GD22482@gate.crashing.org> <27cef66b-df5b-0baa-abac-5532e58bd055@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <27cef66b-df5b-0baa-abac-5532e58bd055@c-s.fr> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 31, 2020 at 05:15:20PM +0100, Christophe Leroy wrote: > Le 31/01/2020 à 16:51, Segher Boessenkool a écrit : > >On Fri, Jan 31, 2020 at 03:37:34PM +0000, Christophe Leroy wrote: > >>When the range is a single page, do a page flush instead. > > > >>+ start &= PAGE_MASK; > >>+ end = (end - 1) | ~PAGE_MASK; > >> if (!Hash) { > >>- _tlbia(); > >>+ if (end - start == PAGE_SIZE) > >>+ _tlbie(start); > >>+ else > >>+ _tlbia(); > >> return; > >> } > > > >For just one page, you get end - start == 0 actually? > > Oops, good catch. > > Indeed you don't get PAGE_SIZE but (PAGE_SIZE - 1) for just one page. You have all low bits masked off in both start and end, so you get zero. You could make the condion read "if (start == end)? Maybe a nicer way to describe what you do is "if start and end are on the same memory page, flush that page." Segher