Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753267Ab2E2HQS (ORCPT ); Tue, 29 May 2012 03:16:18 -0400 Received: from mail-vb0-f46.google.com ([209.85.212.46]:50104 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752821Ab2E2HQQ (ORCPT ); Tue, 29 May 2012 03:16:16 -0400 From: Yong Zhang To: linux-kernel@vger.kernel.org Cc: 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, srivatsa.bhat@linux.vnet.ibm.com Subject: [RFC PATCH 00/10] Cleanup ipi_call_lock[_irq]()/ipi_call_unlock[_irq]() Date: Tue, 29 May 2012 15:15:55 +0800 Message-Id: <1338275765-3217-1-git-send-email-yong.zhang0@gmail.com> X-Mailer: git-send-email 1.7.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2358 Lines: 54 As discussed with Srivatsa [1], it seems there is no need to keep ipi_call_[un]lock_irq() when cpu bring-up/down. Because: 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. In short it's more likely that keeping ipi_call_[un]lock() is leftover before we introduce generic smp helper. This patchset is just to clean things up. [1] http://marc.info/?l=linux-kernel&m=133766786814484&w=2 Yong Zhang (10): hexagon: smp: remove call to ipi_call_lock()/ipi_call_unlock() mn10300: smp: remove call to ipi_call_lock()/ipi_call_unlock() parisc: smp: remove call to ipi_call_lock()/ipi_call_unlock() S390: smp: remove call to ipi_call_lock()/ipi_call_unlock() tile: smp: remove call to ipi_call_lock()/ipi_call_unlock() x86: smp: remove call to ipi_call_lock()/ipi_call_unlock() ia64: smp: remove call to ipi_call_lock_irq()/ipi_call_unlock_irq() SPARC: smp: remove call to ipi_call_lock_irq()/ipi_call_unlock_irq() POWERPC: smp: remove call to ipi_call_lock()/ipi_call_unlock() smp: remove ipi_call_lock[_irq]()/ipi_call_unlock[_irq]() arch/hexagon/kernel/smp.c | 2 -- arch/ia64/kernel/smpboot.c | 2 -- arch/mn10300/kernel/smp.c | 2 -- arch/parisc/kernel/smp.c | 2 -- arch/powerpc/kernel/smp.c | 2 -- arch/s390/kernel/smp.c | 2 -- arch/sparc/kernel/smp_64.c | 6 ++---- arch/tile/kernel/smpboot.c | 10 ---------- arch/x86/kernel/smpboot.c | 9 --------- arch/x86/xen/smp.c | 2 -- include/linux/smp.h | 4 ---- kernel/smp.c | 20 -------------------- 12 files changed, 2 insertions(+), 61 deletions(-) -- 1.7.5.4 -- 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/