Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932210Ab2K0Raf (ORCPT ); Tue, 27 Nov 2012 12:30:35 -0500 Received: from mail-vb0-f46.google.com ([209.85.212.46]:34360 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755889Ab2K0Rad (ORCPT ); Tue, 27 Nov 2012 12:30:33 -0500 MIME-Version: 1.0 In-Reply-To: <20121127170026.GM12969@redhat.com> References: <1353993325.14050.49.camel@ThinkPad-T5421.cn.ibm.com> <20121127154455.GK12969@redhat.com> <20121127163910.GL12969@redhat.com> <20121127170026.GM12969@redhat.com> Date: Tue, 27 Nov 2012 18:30:32 +0100 Message-ID: Subject: Re: [RFC PATCH] Fix abnormal rcu dynticks_nesting values related to async page fault From: Frederic Weisbecker To: Gleb Natapov Cc: Li Zhong , linux-next list , LKML , paulmck@linux.vnet.ibm.com, sasha.levin@oracle.com, avi@redhat.com Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1228 Lines: 33 2012/11/27 Gleb Natapov : > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c > index 4180a87..636800d 100644 > --- a/arch/x86/kernel/kvm.c > +++ b/arch/x86/kernel/kvm.c > @@ -113,7 +113,7 @@ void kvm_async_pf_task_wait(u32 token) > int cpu, idle; > > cpu = get_cpu(); > - idle = idle_cpu(cpu); > + idle = is_idle_task(current); I suggest this part goes to a standalone patch. > put_cpu(); > > spin_lock(&b->lock); > @@ -247,10 +247,7 @@ do_async_page_fault(struct pt_regs *regs, unsigned long error_code) > break; > case KVM_PV_REASON_PAGE_NOT_PRESENT: > /* page is swapped out by the host. */ > - rcu_irq_enter(); > - exit_idle(); > kvm_async_pf_task_wait((u32)read_cr2()); > - rcu_irq_exit(); Hmm, we still need those above around. I believe we just need to add rcu_user_exit() in the beginning of that case. -- 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/