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=-4.1 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 0A92EC433E3 for ; Mon, 17 Aug 2020 12:52:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D07812086A for ; Mon, 17 Aug 2020 12:52:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597668737; bh=LCkDhp0yrQ1H4GBGLsPDHG1MxDxVdl9KXyWjwLTvWPI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=DzT9MdWO9M3HPOg/yHPZwHV5curmM7pEdv7cZkbOHyvpCAewEMX2VOq57tRtwV642 Lafe1W6aNssy27IG8/ZN7SxYgvFKpa0/wHC7PNdcUvMWSjGU1r1fpD+fQFwCKXBsLi fsIh4wxQ1NtiO1RPCfZZ2df6XcRAhVQagkiYzi/o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728449AbgHQMwQ (ORCPT ); Mon, 17 Aug 2020 08:52:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:40734 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726265AbgHQMwN (ORCPT ); Mon, 17 Aug 2020 08:52:13 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BA53020789; Mon, 17 Aug 2020 12:52:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597668732; bh=LCkDhp0yrQ1H4GBGLsPDHG1MxDxVdl9KXyWjwLTvWPI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=pUHLfV+s8fddXGPPQLHHqlb1z8AbfUZG7NYwsP6qnq5K2IVfcprGJsRrncpdFA9ra 0yWmrmbHicohobmmQJY+O/OkOVFL+9FwbcCNn8IymvQarItwreniFbq0rqYpjzwCEx WpS6O+f+OLhmp7XvP9Rx93u16E0rFw/5ea5eTJsA= Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1k7ecV-003ZH0-B9; Mon, 17 Aug 2020 13:52:11 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 17 Aug 2020 13:52:11 +0100 From: Marc Zyngier To: Keqian Zhu Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Steven Price , Andrew Jones , Catalin Marinas , Will Deacon , James Morse , Suzuki K Poulose , wanghaibin.wang@huawei.com Subject: Re: [PATCH 1/2] clocksource: arm_arch_timer: Simplify and fix count reader code logic In-Reply-To: <20200817122415.6568-2-zhukeqian1@huawei.com> References: <20200817122415.6568-1-zhukeqian1@huawei.com> <20200817122415.6568-2-zhukeqian1@huawei.com> User-Agent: Roundcube Webmail/1.4.7 Message-ID: <267c5f9151c39fd2dcd0ce0b09d96545@kernel.org> X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: zhukeqian1@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, steven.price@arm.com, drjones@redhat.com, catalin.marinas@arm.com, will@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, wanghaibin.wang@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-08-17 13:24, Keqian Zhu wrote: > In commit 0ea415390cd3 (clocksource/arm_arch_timer: Use > arch_timer_read_counter > to access stable counters), we separate stable and normal count reader. > Actually > the stable reader can correctly lead us to normal reader if we has no > workaround. Resulting in an unnecessary overhead on non-broken systems that can run without CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND. Not happening. > Besides, in erratum_set_next_event_tval_generic(), we use normal > reader, it is > obviously wrong, so just revert this commit to solve this problem by > the way. If you want to fix something, post a patch that does exactly that. M. -- Jazz is not dead. It just smells funny...