From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756442Ab3C1Pk3 (ORCPT ); Thu, 28 Mar 2013 11:40:29 -0400 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:50568 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753651Ab3C1Pk1 (ORCPT ); Thu, 28 Mar 2013 11:40:27 -0400 Message-ID: <515463D4.60501@linux.vnet.ibm.com> Date: Thu, 28 Mar 2013 21:07:56 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 MIME-Version: 1.0 To: Thomas Gleixner CC: LKML , linux-arch@vger.kernel.org, Linus Torvalds , Andrew Morton , Rusty Russell , Paul McKenney , Ingo Molnar , Peter Zijlstra , Magnus Damm , Richard Henderson , Ivan Kokshaysky , Matt Turner Subject: Re: [patch 07/34] alpha: Use generic idle loop References: <20130321214930.752934102@linutronix.de> <20130321215233.766017538@linutronix.de> In-Reply-To: <20130321215233.766017538@linutronix.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13032815-8878-0000-0000-0000067CD69A Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/22/2013 03:23 AM, Thomas Gleixner wrote: > The core provides a generic idle poll loop. > > Signed-off-by: Thomas Gleixner > Cc: Richard Henderson > Cc: Ivan Kokshaysky > Cc: Matt Turner > --- > arch/alpha/Kconfig | 1 + > arch/alpha/kernel/process.c | 19 ------------------- > arch/alpha/kernel/smp.c | 3 +-- > 3 files changed, 2 insertions(+), 21 deletions(-) > > Index: linux-2.6/arch/alpha/Kconfig > =================================================================== > --- linux-2.6.orig/arch/alpha/Kconfig > +++ linux-2.6/arch/alpha/Kconfig > @@ -17,6 +17,7 @@ config ALPHA > select ARCH_WANT_IPC_PARSE_VERSION > select ARCH_HAVE_NMI_SAFE_CMPXCHG > select GENERIC_SMP_IDLE_THREAD > + select GENERIC_IDLE_LOOP > select GENERIC_CMOS_UPDATE > select GENERIC_STRNCPY_FROM_USER > select GENERIC_STRNLEN_USER > Index: linux-2.6/arch/alpha/kernel/process.c > =================================================================== > --- linux-2.6.orig/arch/alpha/kernel/process.c > +++ linux-2.6/arch/alpha/kernel/process.c > @@ -46,25 +46,6 @@ > void (*pm_power_off)(void) = machine_power_off; > EXPORT_SYMBOL(pm_power_off); > > -void > -cpu_idle(void) > -{ > - current_thread_info()->status |= TS_POLLING; > - > - while (1) { > - /* FIXME -- EV6 and LCA45 know how to power down > - the CPU. */ > - > - rcu_idle_enter(); > - while (!need_resched()) > - cpu_relax(); > - > - rcu_idle_exit(); > - schedule_preempt_disabled(); > - } > -} > - > - (In all my replies, I'm referring to the code in your v2 on your git tree, but replying to the corresponding patches in your v1). So, in alpha, we poll in cpu idle. In the generic implementation in kernel/cpu/idle.c, arch_cpu_idle() is defined as: void __weak arch_cpu_idle(void) { cpu_idle_poll(); } Should it not have been: void __weak arch_cpu_idle(void) { current_set_polling(); cpu_idle_poll(); current_clr_polling(); } instead? Regards, Srivatsa S. Bhat > struct halt_info { > int mode; > char *restart_cmd; > Index: linux-2.6/arch/alpha/kernel/smp.c > =================================================================== > --- linux-2.6.orig/arch/alpha/kernel/smp.c > +++ linux-2.6/arch/alpha/kernel/smp.c > @@ -167,8 +167,7 @@ smp_callin(void) > cpuid, current, current->active_mm)); > > preempt_disable(); > - /* Do nothing. */ > - cpu_idle(); > + cpu_startup_entry(CPUHP_ONLINE); > } > > /* Wait until hwrpb->txrdy is clear for cpu. Return -1 on timeout. */ > >