Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752910Ab3FWNth (ORCPT ); Sun, 23 Jun 2013 09:49:37 -0400 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:52273 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752892Ab3FWNtb (ORCPT ); Sun, 23 Jun 2013 09:49:31 -0400 From: "Srivatsa S. Bhat" Subject: [PATCH 36/45] ia64: smp, tlb: Use get/put_online_cpus_atomic() to prevent CPU offline To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org, walken@google.com, vincent.guittot@linaro.org, laijs@cn.fujitsu.com Cc: rostedt@goodmis.org, wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu, fweisbec@gmail.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Tony Luck , Fenghua Yu , linux-ia64@vger.kernel.org Date: Sun, 23 Jun 2013 19:16:09 +0530 Message-ID: <20130623134605.19094.47993.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130623133642.19094.16038.stgit@srivatsabhat.in.ibm.com> References: <20130623133642.19094.16038.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062313-2000-0000-0000-00000C9A1D73 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2958 Lines: 96 Once stop_machine() is gone from the CPU offline path, we won't be able to depend on disabling preemption to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Tony Luck Cc: Fenghua Yu Cc: linux-ia64@vger.kernel.org Signed-off-by: Srivatsa S. Bhat --- arch/ia64/kernel/smp.c | 12 ++++++------ arch/ia64/mm/tlb.c | 4 ++-- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c index 9fcd4e6..25991ba 100644 --- a/arch/ia64/kernel/smp.c +++ b/arch/ia64/kernel/smp.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -259,8 +260,7 @@ smp_flush_tlb_cpumask(cpumask_t xcpumask) cpumask_t cpumask = xcpumask; int mycpu, cpu, flush_mycpu = 0; - preempt_disable(); - mycpu = smp_processor_id(); + mycpu = get_online_cpus_atomic(); for_each_cpu_mask(cpu, cpumask) counts[cpu] = local_tlb_flush_counts[cpu].count & 0xffff; @@ -280,7 +280,7 @@ smp_flush_tlb_cpumask(cpumask_t xcpumask) while(counts[cpu] == (local_tlb_flush_counts[cpu].count & 0xffff)) udelay(FLUSH_DELAY); - preempt_enable(); + put_online_cpus_atomic(); } void @@ -293,12 +293,12 @@ void smp_flush_tlb_mm (struct mm_struct *mm) { cpumask_var_t cpus; - preempt_disable(); + get_online_cpus_atomic(); /* this happens for the common case of a single-threaded fork(): */ if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1)) { local_finish_flush_tlb_mm(mm); - preempt_enable(); + put_online_cpus_atomic(); return; } if (!alloc_cpumask_var(&cpus, GFP_ATOMIC)) { @@ -313,7 +313,7 @@ smp_flush_tlb_mm (struct mm_struct *mm) local_irq_disable(); local_finish_flush_tlb_mm(mm); local_irq_enable(); - preempt_enable(); + put_online_cpus_atomic(); } void arch_send_call_function_single_ipi(int cpu) diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c index ed61297..8c55ef5 100644 --- a/arch/ia64/mm/tlb.c +++ b/arch/ia64/mm/tlb.c @@ -87,11 +87,11 @@ wrap_mmu_context (struct mm_struct *mm) * can't call flush_tlb_all() here because of race condition * with O(1) scheduler [EF] */ - cpu = get_cpu(); /* prevent preemption/migration */ + cpu = get_online_cpus_atomic(); /* prevent preemption/migration */ for_each_online_cpu(i) if (i != cpu) per_cpu(ia64_need_tlb_flush, i) = 1; - put_cpu(); + put_online_cpus_atomic(); local_flush_tlb_all(); } -- 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/