From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] trace "exit to userspace" event Date: Thu, 14 Oct 2010 13:11:20 +0200 Message-ID: <4CB6E558.6010009@redhat.com> References: <20101005131432.GO11145@redhat.com> <20101007161839.GA31784@amt.cnet> <20101007175655.GG2397@redhat.com> <20101008004917.GA11600@amt.cnet> <20101008164447.GC393@redhat.com> <4CB17D39.7020007@redhat.com> <20101010154625.GR2397@redhat.com> <4CB6DB03.8060408@redhat.com> <20101014102904.GG19207@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:15984 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752785Ab0JNLL0 (ORCPT ); Thu, 14 Oct 2010 07:11:26 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o9EBBPiJ012467 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 14 Oct 2010 07:11:25 -0400 In-Reply-To: <20101014102904.GG19207@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 10/14/2010 12:29 PM, Gleb Natapov wrote: > On Thu, Oct 14, 2010 at 12:27:15PM +0200, Avi Kivity wrote: > > On 10/10/2010 05:46 PM, Gleb Natapov wrote: > > >> > > >> We should log both errno and exit_reason. If we want to be clever, > > >> we can display strerror(errno) if it's nonzero, and exit_reason > > >> otherwise (easy to do in a trace-cmd plugin). > > >> > > >For starters we should remove KVM_EXIT_INTR exit reason. Looking into > > >qemu-kvm history it was never used and there is at least one code path > > >that returns -EINTR and does not set KVM_EXIT_INTR, so exit_reason field > > >contains stale info on exit. > > > > > > > The two issues are unrelated. > > > So what do you propose? I see no issue with my original patch. Record both errno and exit_reason. While they're never both valid at the same time, they're both necessary. -- error compiling committee.c: too many arguments to function