From patchwork Tue May 29 08:27:33 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yong Zhang X-Patchwork-Id: 161704 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id EDA46B6FB4 for ; Tue, 29 May 2012 18:27:55 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751888Ab2E2I1y (ORCPT ); Tue, 29 May 2012 04:27:54 -0400 Received: from mail-vb0-f46.google.com ([209.85.212.46]:49386 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751253Ab2E2I1w (ORCPT ); Tue, 29 May 2012 04:27:52 -0400 Received: by vbbff1 with SMTP id ff1so2323340vbb.19 for ; Tue, 29 May 2012 01:27:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=kor2SO3aJcxz5lmmymlwqX3jzkYhGEbaUwkCRgczlyM=; b=wYy/+myhWcURxPaGk4uUIdy3tQEhIlXGzg3Dd4fWTJPbjeIr0m09tJirvoahJRimrk INL7cJoI5CLCjoufpPSJf16ORDd2ljfZSkuXeaNfZ+aTUct7PCq8lLBCTRX3jHcW+Kjd ptiwJFml/pc2d00zt3B7LBF+AbP14qMUveM+BAsG4lmPJpKZr5NXBsqY6FSTm7AJBRNK AxLswXhertr0AHEI4me+iJQonZVpVhIs27Hq0QMIchBjc7m7WOelI4+V+Qb9bz4gHzpD tk1yQhMoZLro2bBeuTLMPM/rJJdYFiIkMA0+gf7N4bHASw3rlu54hZpKnMyswwe+foov Ne+w== Received: by 10.52.99.227 with SMTP id et3mr9756581vdb.110.1338280071579; Tue, 29 May 2012 01:27:51 -0700 (PDT) Received: from localhost ([61.148.56.138]) by mx.google.com with ESMTPS id g10sm23201424vdk.2.2012.05.29.01.27.41 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 29 May 2012 01:27:50 -0700 (PDT) Date: Tue, 29 May 2012 16:27:33 +0800 From: Yong Zhang To: "Srivatsa S. Bhat" Cc: linux-kernel@vger.kernel.org, ralf@linux-mips.org, sshtylyov@mvista.com, david.daney@cavium.com, nikunj@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com, axboe@kernel.dk, mingo@kernel.org, tglx@linutronix.de, peterz@infradead.org, akpm@linux-foundation.org, "David S. Miller" , sparclinux@vger.kernel.org Subject: [UPDATED] [RFC PATCH 08/10] SPARC: smp: remove call to ipi_call_lock_irq()/ipi_call_unlock_irq() Message-ID: <20120529082732.GA4250@zhy> Reply-To: Yong Zhang References: <1338275765-3217-1-git-send-email-yong.zhang0@gmail.com> <1338275765-3217-9-git-send-email-yong.zhang0@gmail.com> <4FC48272.9040904@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <4FC48272.9040904@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: sparclinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: sparclinux@vger.kernel.org On Tue, May 29, 2012 at 01:31:54PM +0530, Srivatsa S. Bhat wrote: > This looks odd. IRQs must not have been enabled at this point. > Just remove the call to local_irq_enable() that is found a few lines above > this line and then you won't have to add this call to local_irq_disable(). Yeah, have thought about it. But because I was not sure there is special need to enalbe irq that early (don't know much about sparc), I decided to make minor change :) Since we have gotten confirmation from David, I'm sending out the new version. Please check it. Thanks, Yong Acked-by: Srivatsa S. Bhat Acked-by: David S. Miller --- From: Yong Zhang Date: Tue, 29 May 2012 12:56:08 +0800 Subject: [UPDATED] [RFC PATCH 8/10] SPARC: smp: remove call to ipi_call_lock_irq()/ipi_call_unlock_irq() 1) call_function.lock used in smp_call_function_many() is just to protect call_function.queue and &data->refs, cpu_online_mask is outside of the lock. And it's not necessary to protect cpu_online_mask, because data->cpumask is pre-calculate and even if a cpu is brougt up when calling arch_send_call_function_ipi_mask(), it's harmless because validation test in generic_smp_call_function_interrupt() will take care of it. 2) For cpu down issue, stop_machine() will guarantee that no concurrent smp_call_fuction() is processing. And also delay irq enable to after set_cpu_online(). Signed-off-by: Yong Zhang Cc: "David S. Miller" Cc: sparclinux@vger.kernel.org --- arch/sparc/kernel/smp_64.c | 7 +------ 1 files changed, 1 insertions(+), 6 deletions(-) diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c index f591598..781bcb1 100644 --- a/arch/sparc/kernel/smp_64.c +++ b/arch/sparc/kernel/smp_64.c @@ -103,8 +103,6 @@ void __cpuinit smp_callin(void) if (cheetah_pcache_forced_on) cheetah_enable_pcache(); - local_irq_enable(); - callin_flag = 1; __asm__ __volatile__("membar #Sync\n\t" "flush %%g6" : : : "memory"); @@ -124,9 +122,8 @@ void __cpuinit smp_callin(void) while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) rmb(); - ipi_call_lock_irq(); set_cpu_online(cpuid, true); - ipi_call_unlock_irq(); + local_irq_enable(); /* idle thread is expected to have preempt disabled */ preempt_disable(); @@ -1308,9 +1305,7 @@ int __cpu_disable(void) mdelay(1); local_irq_disable(); - ipi_call_lock(); set_cpu_online(cpu, false); - ipi_call_unlock(); cpu_map_rebuild();