From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753358AbaEOJRT (ORCPT ); Thu, 15 May 2014 05:17:19 -0400 Received: from mailapp01.imgtec.com ([195.59.15.196]:44651 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752556AbaEOJRO (ORCPT ); Thu, 15 May 2014 05:17:14 -0400 Message-ID: <53748616.3020109@imgtec.com> Date: Thu, 15 May 2014 10:17:10 +0100 From: James Hogan User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Peter Zijlstra , , Thomas Gleixner CC: , , , , LKML , Catalin Marinas , Will Deacon , ARM Kernel List , linux-metag Subject: Re: [RFC][PATCH 6/8] sched,idle: Avoid spurious wakeup IPIs References: <20140411134243.160989490@infradead.org> <20140411135218.478299389@infradead.org> <20140509141520.GV2844@laptop.programming.kicks-ass.net> <536CEB7E.9080007@imgtec.com> In-Reply-To: <536CEB7E.9080007@imgtec.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.154.101] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, On 09/05/14 15:51, James Hogan wrote: > On 09/05/14 15:15, Peter Zijlstra wrote: >> Most archs have (x86) hlt or (arm) wfi like idle instructions, and if >> that is your only possible idle function, you'll require the interrupt >> to wake up and there's really no point to having the POLLING bit. >> >> Lastly, having the POLLING bit and not needing it is similarly non-fatal. >> > > Thanks. I think the flag can go for Metag then. I suggest the following > patch. This is still bust in linux-next. What's the status of this patch? Thanks James > > From 15dd3f9cc18bdb1c8c4d2c395778421022250aa8 Mon Sep 17 00:00:00 2001 > From: James Hogan > Date: Fri, 9 May 2014 15:36:21 +0100 > Subject: [PATCH] metag: Remove TIF_POLLING_NRFLAG > > The Meta idle function jumps into the interrupt handler which > efficiently blocks waiting for the next interrupt when it reads the > interrupt status register (TXSTATI). No other (polling) idle functions > can be used, therefore TIF_POLLING_NRFLAG is unnecessary, so lets remove > it. > > Peter Zijlstra said: >> Most archs have (x86) hlt or (arm) wfi like idle instructions, and if >> that is your only possible idle function, you'll require the interrupt >> to wake up and there's really no point to having the POLLING bit. > > Signed-off-by: James Hogan > Cc: Peter Zijlstra > --- > arch/metag/include/asm/thread_info.h | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/arch/metag/include/asm/thread_info.h b/arch/metag/include/asm/thread_info.h > index b19e9c588a16..47711336119e 100644 > --- a/arch/metag/include/asm/thread_info.h > +++ b/arch/metag/include/asm/thread_info.h > @@ -117,10 +117,8 @@ static inline int kstack_end(void *addr) > #define TIF_SECCOMP 5 /* secure computing */ > #define TIF_RESTORE_SIGMASK 6 /* restore signal mask in do_signal() */ > #define TIF_NOTIFY_RESUME 7 /* callback before returning to user */ > -#define TIF_POLLING_NRFLAG 8 /* true if poll_idle() is polling > - TIF_NEED_RESCHED */ > -#define TIF_MEMDIE 9 /* is terminating due to OOM killer */ > -#define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint instrumentation */ > +#define TIF_MEMDIE 8 /* is terminating due to OOM killer */ > +#define TIF_SYSCALL_TRACEPOINT 9 /* syscall tracepoint instrumentation */ > > > #define _TIF_SYSCALL_TRACE (1<