From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH] KVM: Get rid of KVM_REQ_KICK Date: Thu, 6 May 2010 16:56:37 -0300 Message-ID: <20100506195637.GD3432@amt.cnet> References: <1272896348-13514-1-git-send-email-avi@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:51997 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757681Ab0EFULO (ORCPT ); Thu, 6 May 2010 16:11:14 -0400 Received: from int-mx05.intmail.prod.int.phx2.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.18]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o46KBEhe015586 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 6 May 2010 16:11:14 -0400 Content-Disposition: inline In-Reply-To: <1272896348-13514-1-git-send-email-avi@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, May 03, 2010 at 05:19:08PM +0300, Avi Kivity wrote: > KVM_REQ_KICK poisons vcpu->requests by having a bit set during normal > operation. This causes the fast path check for a clear vcpu->requests > to fail all the time, triggering tons of atomic operations. > > Fix by replacing KVM_REQ_KICK with a vcpu->guest_mode atomic. > > Signed-off-by: Avi Kivity > --- > arch/x86/kvm/x86.c | 17 ++++++++++------- > include/linux/kvm_host.h | 1 + > 2 files changed, 11 insertions(+), 7 deletions(-) Reviewed-by: Marcelo Tosatti