From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vb0-f51.google.com (mail-vb0-f51.google.com [209.85.212.51]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 5D4F6B6EEB for ; Tue, 29 May 2012 17:18:12 +1000 (EST) Received: by vbip1 with SMTP id p1so2362122vbi.38 for ; Tue, 29 May 2012 00:18:08 -0700 (PDT) From: Yong Zhang To: linux-kernel@vger.kernel.org Subject: [RFC PATCH 09/10] POWERPC: smp: remove call to ipi_call_lock()/ipi_call_unlock() Date: Tue, 29 May 2012 15:16:04 +0800 Message-Id: <1338275765-3217-10-git-send-email-yong.zhang0@gmail.com> In-Reply-To: <1338275765-3217-1-git-send-email-yong.zhang0@gmail.com> References: <1338275765-3217-1-git-send-email-yong.zhang0@gmail.com> Cc: axboe@kernel.dk, sshtylyov@mvista.com, nikunj@linux.vnet.ibm.com, david.daney@cavium.com, peterz@infradead.org, akpm@linux-foundation.org, ralf@linux-mips.org, Paul Mackerras , srivatsa.bhat@linux.vnet.ibm.com, tglx@linutronix.de, paulmck@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, mingo@kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Yong Zhang 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. Signed-off-by: Yong Zhang Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: linuxppc-dev@lists.ozlabs.org --- arch/powerpc/kernel/smp.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index e4cb343..e1417c4 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -571,7 +571,6 @@ void __devinit start_secondary(void *unused) if (system_state == SYSTEM_RUNNING) vdso_data->processorCount++; #endif - ipi_call_lock(); notify_cpu_starting(cpu); set_cpu_online(cpu, true); /* Update sibling maps */ @@ -601,7 +600,6 @@ void __devinit start_secondary(void *unused) of_node_put(np); } of_node_put(l2_cache); - ipi_call_unlock(); local_irq_enable(); -- 1.7.5.4