Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752697Ab3FWNrk (ORCPT ); Sun, 23 Jun 2013 09:47:40 -0400 Received: from e23smtp01.au.ibm.com ([202.81.31.143]:49482 "EHLO e23smtp01.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752589Ab3FWNrf (ORCPT ); Sun, 23 Jun 2013 09:47:35 -0400 From: "Srivatsa S. Bhat" Subject: [PATCH 28/45] KVM: 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, Gleb Natapov , Paolo Bonzini , kvm@vger.kernel.org Date: Sun, 23 Jun 2013 19:14:11 +0530 Message-ID: <20130623134407.19094.28802.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-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062313-1618-0000-0000-00000421F1D9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1835 Lines: 58 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: Gleb Natapov Cc: Paolo Bonzini Cc: kvm@vger.kernel.org Signed-off-by: Srivatsa S. Bhat --- virt/kvm/kvm_main.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 302681c..5bbfa30 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -174,7 +174,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req) zalloc_cpumask_var(&cpus, GFP_ATOMIC); - me = get_cpu(); + me = get_online_cpus_atomic(); kvm_for_each_vcpu(i, vcpu, kvm) { kvm_make_request(req, vcpu); cpu = vcpu->cpu; @@ -192,7 +192,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req) smp_call_function_many(cpus, ack_flush, NULL, 1); else called = false; - put_cpu(); + put_online_cpus_atomic(); free_cpumask_var(cpus); return called; } @@ -1707,11 +1707,11 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu) ++vcpu->stat.halt_wakeup; } - me = get_cpu(); + me = get_online_cpus_atomic(); if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) if (kvm_arch_vcpu_should_kick(vcpu)) smp_send_reschedule(cpu); - put_cpu(); + put_online_cpus_atomic(); } EXPORT_SYMBOL_GPL(kvm_vcpu_kick); #endif /* !CONFIG_S390 */ -- 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/