From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH RT 3.18] irq_work: Provide a soft-irq based queue Date: Thu, 23 Apr 2015 09:12:39 +0200 Message-ID: <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> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Steven Rostedt , Sebastian Andrzej Siewior , RT , Linux Kernel Mailing List To: Mike Galbraith Return-path: Received: from david.siemens.de ([192.35.17.14]:60327 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750746AbbDWHMp (ORCPT ); Thu, 23 Apr 2015 03:12:45 -0400 In-Reply-To: <1429772482.3419.40.camel@gmail.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: 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 =3D IS_ENABLED(CONFIG_PREEMPT_RT_FULL); >>> + bool raise =3D 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(); >>> =20 >>> -#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,=20 >>> 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=20 >> bool >> variable. Is that pattern OK for Linux? Does it compile in all=20 >> supported >> optimization levels of all supported compilers? >=20 > 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: =2E./kernel/irq_work.c: In function =E2=80=98irq_work_queue_on=E2=80=99= : =2E./kernel/irq_work.c:85:17: error: =E2=80=98hirq_work_list=E2=80=99 u= ndeclared (first use in this function) &per_cpu(hirq_work_list, cpu)); Jan --=20 Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html