From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiaotian Feng Subject: Re: [PATCH -V2] acpi: don't cond_resched if irq is disabled Date: Mon, 28 Dec 2009 14:02:30 +0800 Message-ID: <4B3849F6.1080403@redhat.com> References: <20091210100907.GA2446@ucw.cz> <1260446205-16868-1-git-send-email-dfeng@redhat.com> <4B20E7B2.1010208@suse.de> <1260510373.10543.17.camel@minggr.sh.intel.com> <4B223185.80202@suse.de> <20091211161549.GA15760@elf.ucw.cz> <4B227275.5010201@gmail.com> <20091211173424.GC15760@elf.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:9025 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750818AbZL1GDR (ORCPT ); Mon, 28 Dec 2009 01:03:17 -0500 In-Reply-To: <20091211173424.GC15760@elf.ucw.cz> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Pavel Machek Cc: Alexey Starikovskiy , Alexey Starikovskiy , Lin Ming , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Len Brown , "Moore, Robert" On 12/12/2009 01:34 AM, Pavel Machek wrote: > >>>> If there are none, fine. >>>> >>>>> #ifdef CONFIG_PREEMPT >>>>> # define preemptible() (preempt_count() == 0&& !irqs_disabled()) >>>>> # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) >>>>> #else >>>>> # define preemptible() 0 >>>>> # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET >>>>> #endif >>>>> >>> >>> Well, normally we want low latency even for !CONFIG_PREEMPT kernels. >>> >>> Actually, explicit preemption points are NOPs for CONFIG_PREEMPT >>> kernels, right? > >> Right. Do you have code? > > I'd prefer to spend my time with patches to areas that actually do > take cleanup patches. What's the status of this now? We can still see the sleeping function call warning or enable irq at resume stage. If acpi wants low latency even for !CONFIG_PREEMPT kernels, what's wrong with V2 patch? We should not set any preemption points in irq or atomic. Since we have a simple fix, and it did fix bugs, why should we make things more complex? > Pavel