Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753903AbbDWHTb (ORCPT ); Thu, 23 Apr 2015 03:19:31 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:37237 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751073AbbDWHT3 (ORCPT ); Thu, 23 Apr 2015 03:19:29 -0400 Message-ID: <1429773566.3419.42.camel@gmail.com> Subject: Re: [PATCH RT 3.18] irq_work: Provide a soft-irq based queue From: Mike Galbraith To: Jan Kiszka Cc: Steven Rostedt , Sebastian Andrzej Siewior , RT , Linux Kernel Mailing List Date: Thu, 23 Apr 2015 09:19:26 +0200 In-Reply-To: <55389B67.3000703@siemens.com> References: <552FC1FE.4020406@siemens.com> <552FC6B1.1040000@linutronix.de> <552FC72A.8060709@siemens.com> <20150416111041.66043164@gandalf.local.home> <552FD55F.8000105@siemens.com> <552FE320.6050601@siemens.com> <1429517036.3226.9.camel@gmail.com> <1429769505.3419.9.camel@gmail.com> <55389632.50308@siemens.com> <1429772482.3419.40.camel@gmail.com> <55389B67.3000703@siemens.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.0 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2650 Lines: 67 On Thu, 2015-04-23 at 09:12 +0200, Jan Kiszka wrote: > On 2015-04-23 09:01, Mike Galbraith wrote: > > On Thu, 2015-04-23 at 08:50 +0200, Jan Kiszka wrote: > > > On 2015-04-23 08:11, Mike Galbraith wrote: > > > > @@ -103,6 +98,9 @@ EXPORT_SYMBOL_GPL(irq_work_queue_on); > > > > /* Enqueue the irq work @work on the current CPU */ > > > > bool irq_work_queue(struct irq_work *work) > > > > { > > > > + bool realtime = IS_ENABLED(CONFIG_PREEMPT_RT_FULL); > > > > + bool raise = false; > > > > + > > > > /* Only queue if not already pending */ > > > > if (!irq_work_claim(work)) > > > > return false; > > > > @@ -110,25 +108,22 @@ bool irq_work_queue(struct irq_work *wor > > > > /* Queue the entry and raise the IPI if needed. */ > > > > preempt_disable(); > > > > > > > > -#ifdef CONFIG_PREEMPT_RT_FULL > > > > - if (work->flags & IRQ_WORK_HARD_IRQ) { > > > > + if (realtime && (work->flags & IRQ_WORK_HARD_IRQ)) { > > > > if (llist_add(&work->llnode, > > > > this_cpu_ptr(&hirq_work_list))) > > > > > > This boils down to > > > > > > #ifdef CONFIG_X > > > some_type x; > > > #endif > > > ... > > > > > > if (IS_ENABLED(CONFIG_X) && ...) > > > use(x); > > > > > > And here we even have an indirection for IS_ENABLED via that > > > local > > > bool > > > variable. Is that pattern OK for Linux? Does it compile in all > > > supported > > > optimization levels of all supported compilers? > > > > I hope it all goes away, that being what IS_ENABLED() is there for. > > Hope is good - but not enough here: it breaks the build under > !CONFIG_X, even the case without the bool var. > > CC kernel/irq_work.o > In file included from ../include/asm-generic/percpu.h:6:0, > from ../arch/x86/include/asm/percpu.h:522, > from ../arch/x86/include/asm/current.h:5, > from ../arch/x86/include/asm/processor.h:15, > from ../arch/x86/include/asm/irq_work.h:4, > from ../include/linux/irq_work.h:47, > from ../kernel/irq_work.c:11: > ../kernel/irq_work.c: In function ‘irq_work_queue_on’: > ../kernel/irq_work.c:85:17: error: ‘hirq_work_list’ undeclared > (first use in this function) > &per_cpu(hirq_work_list, cpu)); Aw poo, so that's just what I _thought_ it was for. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/