From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753618Ab2IUMEO (ORCPT ); Fri, 21 Sep 2012 08:04:14 -0400 Received: from e23smtp01.au.ibm.com ([202.81.31.143]:53512 "EHLO e23smtp01.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752503Ab2IUMED (ORCPT ); Fri, 21 Sep 2012 08:04:03 -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 Date: Fri, 21 Sep 2012 17:30:20 +0530 Message-Id: <20120921120019.27611.66093.sendpatchset@codeblue> In-Reply-To: <20120921115942.27611.67488.sendpatchset@codeblue> References: <20120921115942.27611.67488.sendpatchset@codeblue> Subject: [PATCH RFC 2/2] kvm: Be courteous to other VMs in overcommitted scenario in PLE handler x-cbid: 12092112-1618-0000-0000-000002855BB2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Raghavendra K T When PLE handler fails to find a better candidate to yield_to, it goes back and does spin again. This is acceptable when we do not have overcommit. But in overcommitted scenarios (especially when we have large number of small guests), it is better to yield. Reviewed-by: Srikar Dronamraju Signed-off-by: Raghavendra K T --- virt/kvm/kvm_main.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8323685..713b677 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1660,6 +1660,10 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me) } } } + /* In overcommitted cases, yield instead of spinning */ + if (!yielded && rq_nr_running() > 1) + schedule(); + kvm_vcpu_set_in_spin_loop(me, false); /* Ensure vcpu is not eligible during next spinloop */