Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754424Ab2J2OLo (ORCPT ); Mon, 29 Oct 2012 10:11:44 -0400 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:36483 "EHLO e28smtp04.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753717Ab2J2OLm (ORCPT ); Mon, 29 Oct 2012 10:11:42 -0400 From: Raghavendra K T To: Peter Zijlstra , "H. Peter Anvin" , Marcelo Tosatti , Ingo Molnar , Avi Kivity , Rik van Riel Cc: Srikar , "Nikunj A. Dadhania" , KVM , Raghavendra K T , Jiannan Ouyang , Chegu Vinod , "Andrew M. Theurer" , LKML , Srivatsa Vaddagiri , Gleb Natapov , Andrew Jones Date: Mon, 29 Oct 2012 19:37:03 +0530 Message-Id: <20121029140702.15448.56932.sendpatchset@codeblue> In-Reply-To: <20121029140621.15448.92083.sendpatchset@codeblue> References: <20121029140621.15448.92083.sendpatchset@codeblue> Subject: [PATCH V2 RFC 2/3] kvm: Handle yield_to failure return code for potential undercommit case x-cbid: 12102914-5564-0000-0000-000005135878 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1999 Lines: 76 From: Raghavendra K T Also we do not update last boosted vcpu in failure cases. Reviewed-by: Srikar Dronamraju Signed-off-by: Raghavendra K T --- virt/kvm/kvm_main.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index be70035..e376434 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1639,6 +1639,7 @@ bool kvm_vcpu_yield_to(struct kvm_vcpu *target) { struct pid *pid; struct task_struct *task = NULL; + bool ret = false; rcu_read_lock(); pid = rcu_dereference(target->pid); @@ -1646,17 +1647,15 @@ bool kvm_vcpu_yield_to(struct kvm_vcpu *target) task = get_pid_task(target->pid, PIDTYPE_PID); rcu_read_unlock(); if (!task) - return false; + return ret; if (task->flags & PF_VCPU) { put_task_struct(task); - return false; - } - if (yield_to(task, 1)) { - put_task_struct(task); - return true; + return ret; } + ret = yield_to(task, 1); put_task_struct(task); - return false; + + return ret; } EXPORT_SYMBOL_GPL(kvm_vcpu_yield_to); @@ -1697,6 +1696,7 @@ bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu) return eligible; } #endif + void kvm_vcpu_on_spin(struct kvm_vcpu *me) { struct kvm *kvm = me->kvm; @@ -1727,11 +1727,12 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me) continue; if (!kvm_vcpu_eligible_for_directed_yield(vcpu)) continue; - if (kvm_vcpu_yield_to(vcpu)) { + + yielded = kvm_vcpu_yield_to(vcpu); + if (yielded > 0) kvm->last_boosted_vcpu = i; - yielded = 1; + if (yielded) break; - } } } kvm_vcpu_set_in_spin_loop(me, false); -- 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/